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Know a little something about maintenance, fixing, tuning, or modifying MX, offroad, & dual sport motorcycles, ATV or UTV? Or, maybe you have mad skills riding or racing them? Whatever the case, if you have valuable knowledge & experiences that relates to motorcycles, ATVs, or UTVs, please help your fellow riders by sharing your best tips, tricks, and how to articles.

    Billy@JEPistons
    Checking and adjusting valves is considered routine maintenance on high-performance four-stroke engines used throughout the powersports industry. Valve clearance inspections are not hard to perform and are well within the capability of most owners. However, there are tips and tricks that can make the job go smoother and yield better results. The JE Pistons team has been building and testing engines for over 70 years, and as a result, we know what it takes to do the job to a high standard.

    With years of experience in four-stroke engines of all types, JE is no stranger to the valve adjustments and maintenance.
    Whether you own a dirt bike, ATV, street bike, or any other four-stroke equipped machine, chances are your owner’s manual outlines when your engine’s valve clearances should be checked. Depending on the application, the inspection interval may vary from 15 hours to 15,000 miles. Checking clearances at the specified intervals is incredibly important to ensure the engine continues to run optimally and lasts a long time. Also, as a rule of thumb, anytime the top-end of the engine is disassembled, it is best practice to check valve clearances.

    Any time you have the top end apart to replace the piston, you should check your valve clearance and adjust as necessary.
    Before servicing your engine, you will need your machine’s factory service manual. The service manual is required because it specifies the required clearances, torque specs, and other information imperative to performing the task. The outline we’re providing should be considered supplemental to the information in your service manual and is in no way a comprehensive substitute.
    To tackle this job, you’ll typically need the following tools and supplies:
     Lash/feeler gauges  Metric wrenches  Metric sockets  Clean rags or towels  Screwdrivers  Caliper In most cases, specialty tools aren’t utilized, however, if they are, you’ll find that information in your service manual.

    A critical tool to measuring valve clearance is a set of feeler gauges.
    Since the engine is going to be partially opened up and exposed, it is best to work on a clean machine. If your machine is dirty, take the time to clean it thoroughly so the risk of contaminating the engine with debris is lessened. Prioritize cleaning the cylinder head cover and surrounding area.

    Chances are you're not working on a new bike, so be sure the area around the cam cover is clean to avoid unwanted debris.
    We’ll begin outlining the procedure with the removal of the cylinder head cover. You’ll likely need to remove your seat, fuel tank and various other components before this. These items should be easy to remove, and your service manual should provide sufficient guidance. When removing the cylinder head cover, be extremely careful not to allow dirt to fall into the cylinder head.

    If you're working on an engine still in the bike, you'll need to remove your seat and tank, along with any other components hindering your access to the cam cover.
    Next, the valvetrain will need to be positioned so that the clearances can be checked. Most service manuals specify setting the valvetrain so that the piston is at top dead center (TDC) on the compression stroke. Setting the valvetrain at this position ensures that the cam, or cams, are on their base circles and that neither the intake or exhaust valves are open. The base circle of the cam is the circular portion of the cam which does not influence valve lift.
    As an aside and for future reference, while it is sensible to follow the service manuals recommendations on setting the piston position and engine stroke when the engine is assembled, it is not necessary, especially when working on an engine that is being rebuilt. Checking valve clearance can also be accomplished with the cylinder head removed from the engine and positioning the cam lobes opposite the lifter buckets to ensure the clearance measurements are taken with the cam on its base circle.

    Whether the head is still on the engine or you're working on it separately, be sure the engine is either at TDC or the cam lobes are resting somewhere on their base circle and not applying pressure to the buckets like they would when opening valves.
    Your service manual outlines the required procedure to set the engine on its compression stroke at TDC. Most engines have mating alignment marks on the crankshaft and engine case as well as the cam gear and cylinder head. It is imperative that you know and understand how to utilize these reference points because they are used to correctly set the cam timing after any valve clearance adjustments have been made.
    Once you’ve positioned the cams correctly, valve clearance measurements can be made using lash (feeler) gauges. Lash gauge measurements can be tricky due to surrounding geometry and inexperience on the user’s part. To obtain the most accurate measurement, it is essential that the lash gauge is inserted between the cam and lifter bucket as close to parallel as possible. To facilitate parallel entry, bend the lash gauges as necessary so that their tips can easily slide between the cam and lifter bucket.

    Measure valve clearance by inserting your lash gauge(s) between the cam lobe and lifter bucket.
    Accurate lash gauge measurements are subjective because they are based on feel. Ideally, the most accurate valve clearance measurements are obtained when the lash gauge passes between the cam and lifter bucket with a slight drag. Gauges that pass through easily or must be forced through should be considered too thin or too thick, respectively. When this occurs, other gauges should be tried, or, if you’re between sizes, the average of the two should be utilized as the valve clearance.

    Begin by the using the gauge equal to the median recommended valve clearance measurement in your manual. You may have to move up or down a couple sizes until you find the size that slides between the cam lobe and bucket with a slight drag. Record this measurement for each valve.
    After each of the intake and exhaust valve clearances has been recorded, they should be compared to the service specifications outlined in your service manual. If the valve clearances fall within the manufacturer’s recommended range, no further work is required. However, if the clearances are outside of the specifications, determining what adjustments need to be made is the next step. To do this, unless the current valve shim thicknesses are known, the cylinder head will have to be disassembled so that the shims can be removed and measured.
    Follow the necessary procedures outlined in your service manual to slacken the cam chain, remove the cam cap, cams, and lifter buckets. When removing the cam cap, be sure to follow any recommended removal/tensioning sequences. Once the cam chain is free, use a piece of wire to secure it to the cylinder head. If it happens to fall in the chaincase, a pen magnet can be used to fish it out.
     
    Be sure to slacken the cam chain before attempting removal. Remove the camshaft(s) and secure the cam chain so it doesn't fall in the cases.
    To remove the lifter buckets, a pen magnet or valve lapping tool are both excellent aids to utilize. When extracting the lifter buckets from their bores, be very careful and keep tabs on whether or not the valve shim sticks to the underside of the bucket. Oil underneath the lifter buckets makes sticking shims a common occurrence.

    Use a pen magnet or lapping tool to remove the buckets. Be careful of shims that may stick on the underside of buckets.
    Through engine operation, the lifter buckets mate to their respective bores so they should never be mixed around. To help keep track of things, draw out a simple cylinder head diagram on a piece of paper so that the lifter buckets and all the measurements can be tracked. Proceed to remove any remaining valve shims from the cylinder head. Once the valve shims have been removed, measure the shim thicknesses and the diameter of shims used.
     
    Drawing a simple diagram can help you keep track of what buckets and shims came from where. Once everything is removed, confirm your shim measurements.
    To determine what valve shim adjustments should be made, a simple formula is used:
    New Shim Thickness = Recorded Clearance - Specified Clearance + Old Shim Thickness
    Calculate the necessary new shim thicknesses for all the clearances that are out of spec. Valve shims are available from most OEMs, but helpful shim kits that come with an assortment of sizes are also available from the aftermarket. Before sourcing shims, you’ll need to determine the diameter of the shim you need because there are a handful of different shim diameters used within the industry. Shown below are the standard shim diameters.
    Size (mm)
    7.48 (Japanese) 9.48 (Japanese) 8.90 (KTM) 10.00 (KTM)
    Shim assortment kits are available from various aftermarket suppliers, just be sure you know what shim diameter your machine takes before ordering. This kit was sourced from ProX Racing Parts.
    When calculating what new shim thicknesses are required, it is best to target the specified clearance on the upper end of the prescribed clearance range. This is advised because valve clearances usually diminish over time. Valve shims are available in 0.025mm increments, so the shims that can be utilized will also influence the new clearances that can be achieved.
    Once you have the correct shims in hand, the valvetrain can be reassembled. Use engine oil to lubricate the valve shims and carefully install them. The lifter buckets should also be lubed before installation. When inserting the lifter buckets into their respective bores, ensure that the buckets bottom on the shims and at no point comes back up. If the bucket comes back up upon installation, occasionally the shim will stick to it and become displaced. The engine can quickly be severely damaged if the shim is not seated correctly between the valve stem and lifter bucket. 

    Using engine oil and assembly lube when reassembling your shims, buckets, and cams helps prevent premature wear and also helps your shims stay in place while re-inserting buckets.
    Pay close attention to your service manual during installation of the cams and when setting cam timing. Double check that the crankshaft is in its correct position. If you’re working on a twin cam engine, it is best to install the camshaft that resides opposite of the chain tensioner first (typically the exhaust cam), pull the chain taught from the crankshaft, orient the cam gear correctly, and then wrap the chain around the gear. Once this is accomplished, the remaining cam can be oriented correctly and the chain wrapped around it. Double check orientation of all components and that timing has been set correctly. Be sure to use engine oil to lube the cam bearing bores upon installation.
     
    Make sure your timing marks on your crankshaft are lined up, then reinstall your cam(s). It's important to make sure the timing marks on the crankshaft and cam(s) remain lined up simultaneously when reinstalling the cam chain.
    Click here for a more in-depth guide to setting cam timing.
    When installing the cam cap, ensure the torque specs and sequences outlined in your service manual are followed. Deviations from either can cause the cam bearings to wear prematurely. Once the cams have been secured, use lash gauges to confirm the new valve clearances match the clearances that were calculated. Any deviations that are found should be carefully scrutinized because they may be indicative of calculation errors or shims that are not seated correctly. If there is a hint of a problem at this point, it is imperative that it is thoroughly understood and corrected before proceeding.

    Be sure to follow the correct torque sequence and specifications when re-installing cam caps.
    Assuming everything checks out, the cam chain can be tensioned. Follow the procedure outlined in your service manual to do so. Once the tension has been set, rotate the engine through at least four complete revolutions. Doing so will help the automatic chain tensioners to set the correct initial tension and confirm that the engine has been timed correctly. Position the piston at TDC on the compression stroke and check that all timing features on the crank and cams remain in their specified positions.
    Complete the job by carefully reinstalling the cylinder head cover, making sure to torque those bolts in a star sequence to recommended specs. Once the rest of the machine is buttoned up, it’s time to get back to riding!
     
    More Tech Articles from JE Pistons
    Erik Marquez
    Riders all over have reasons to store a bike, winter or going away to school for a year, extended work trip and many other reasons.
    The good news is the process to store it is the same no matter the reason.

    Good storage prep is the key to a bike that can be brought back online not just quickly, but at little to no cost, no repairs required.
    How great would it be to come home after a year, spend just a few min in the garage to get your bike ready to ride?

    I will discuss 6 key areas. Understanding there is no one best way for all so this article is just A Way.
    A way that has proven to work countless times on bikes stored over winter, or several years be me personally, and hundreds of others I've made these suggestions to.

    If you have a way that works for you and results in fast startup, no repairs needed post storage perhaps this article is not for you. If you have never stored a bike or have and would like to read some ideas that might help you avoid some issue you had last time, read on.

    As always, this article is not a comprehensive step by step procedure. It does assume the reader has a basic understanding of using tools, working on a motorcycle, safety and precautions when doing both. If your not comfortable removing your spark plug, don't know how to get your motor to TDC, then please don't. Hire a qualified mechanic or even better,  bribe a qualified friend to come over and walk you through it.
    Exterior Preparation Fuel System Electrical System Engine & Cooling System Storage Location Bringing the bike back to life So let's get into it.
    Exterior Preparation
    Start by cleaning the entire bike with a mild detergent and water. Avoid spraying bearings, seals, electrical connectors and components directly so to not force water into them. If you use a pressure wash, be VERY careful of this.
    If possible, start and ride the bike to evaporate any water trapped in the motor and drag your brakes to dry them as much as possible. Use compressed air if you have it, or even a shop vac set to vent. Clean your chain with a plastic bristled brush and chain cleaner. Spray your clean chain with a petroleum based chain lube, and wipe off the excess with a shop rag. If you have an o-ring chain, make sure to use o-ring safe lube. While you’re still in lube mode, take your WD-40 and spray down the foot peg pivots, kick start pivot, folding shifter pivot and lever pivots. If it can rust, give it a shot or corrosion preventive. Take the time to get a good overall inspection of brake pads, suspension linkage, chain and sprockets for wear... Great time to get those things ordered so they are waiting when it's time to ride again.  If your motorcycle is equipped with grease zerk fittings, go ahead and give them a few squirts of quality grease and wipe off the excess that inevitably oozes out. Lastly, air up the tires to spec.

    Fuel System

    There are different methods of preparing fuel systems for storage. Steel tanks, plastic tanks, carbs, or FI, long term (more than 4 months) short term, or indefinite (or unknown) storage times all give some options. As I started this article, I'll lay out A way, a way that has proven to me and many others to work well in a variety of situations. If your bike has a steel fuel tank, you have two choices both are concerned with keeping tank rust a bay. If you will be putting the bike back in service in 4 or so months or less, Treat the
    fuel with a known quality fuel storage chemical.. I have had great luck with Stabil 360.
                                                                                                                                                          
    Its claim to off gas corrosion preventive protecting tank areas above fuel line has shown to work well in a 90 bike training fleet I manage, these bikes sit for weeks to months unused. Making them very representative of the average rider’s stored bike. 
    Fill the tank to the brim, leaving as little air space as possible. Filling the tank completely will greatly help it from rusting, which is a major issue in some areas. Plastic fuel tanks are more forgiving, but even so I prefer to drain them completely. Another fuel option is, filling with race gas, something like Sunoco SS 100  or VP C10, C12, ect . Race gas has no ethanol and overall has shown to be very Stabil for long term storage. Once the fuel has been stabilized, start the motorcycle and let the fuel circulate throughout the entire system.
    If storage will be very long term or length unknown and you have a steel tank... consider draining and fogging the tank with fogging oil. Fogging oil will be available at some auto parts stores and most boat/marine shops. And of course is available online easily.
    A fogging oil I have found readily available, reasonably priced and works well is  
    Lastly, heat....if your living or storing your bike in extreme high temps, Texas summers in a shad, or no AC garage... highly recommend draining the entire fuel system no matter carbureted  or FI, steel or plastic tank. The fuel will evaporate in the high temps leaving behind a residue you don't want to deal with. 
     Electrical System
    If your bike has a battery, steps to keep it viable are needed. To keep it fully charged which extends battery life overall, but especially in storage a battery tender is suggested. A brand I like a lot for its effectiveness is Battery Tender. And the Battery Tender
    JR is a perfect fit for storage needs. 
    A bonus is it comes with a  pigtail you can attach to the battery, so you have a "permanent" SAE plug available for hooking up your tender now, or later to keep the battery charged, or even hook up a battery charger should the need arise later. 
    Battery life has lot to do with the climate it’s stored in. If your bike is stored in an unheated area, remove the battery from the bike and store it in a heated a space. Basements, storeroom or a even a closet will work. The more stable and moderate the temp the better.  Keeping the battery from freezing along with a Battery Tender or like product will keep the battery at its best.

    Another thing I feel is important as regular servicing but helpful in storage prep is cleaning and protecting your electrical connections. Yes it's time consuming, but so is diagnosing electrical gremlins next year because a little water snuck in during that creek crossing or from the pressure washer. If cleaning and protecting connections is a regular part of your bike maintenance you can likely skip this step. If not, take the time now to disconnect, inspect each connector, and spray with a cleaner and corrosion protector like 
     
    A google search will find it widely available...If not this, then another product labeled to clean and protect electrical connectors 

    Engine oil & Cooling System
    A fresh oil change should be done before you store your bike. Do this after the wash and dry, best bet is do it as a last thing after running the motor to warm.
    Dirty engine oil contains corrosive acids and other contaminants that you do not want to leave in the engine during storage. If you are in a coastal region or area with high humidity fogging oil should be applied through the spark plug hole. Clean well around the spark plug and dispose of it. With the spark plug out, shoot a few sprays down the spark hole and turn the motor over a few times leaving it at TDC. Once the fogging oil has been applied, install a fresh spark plug.

    Next is your cooling system Make sure that the coolant is up to spec. Fresh coolant is a good idea, if it’s been awhile. With any motorcycle fluid, when in doubt change it. Brake and clutch fluid are hydroscopic, meaning they absorb water. You do not want that "wet" fluid in your clutch or brake system at all, but for sure not in storage. There are moisture meters available cheaply to test your fluids, they are specific to type, so DOT 3, DOT4, DOT5.1 .  If you don't want to buy and use one, just change the fluid before storage and make sure reservoirs are topped off. If there is any doubt replace that fluid.

    Storage Location
    Great so your bike is all prepped for storage, one last decision. Location, Location, Location.....If you have a choice, put it in the same room conditions you would but your grandmother (your favorite grandmother). The less you expose the motorcycle to extreme temperature fluctuations and humidity the better. Once the location has been chosen, put the motorcycle up on a stand. Using a stand keeps the weight off the tires and suspension. If a stand is not option, using a piece of wood to park the motorcycle on will keep the tires from sitting in dirt, cold concrete, or damaging the tile or carpet in the spare bedroom rotting (what don't blame me if your significant other does not allow you to park your bikes in the house, mine does..LOL). Once the motorcycle is in its home for storage, throw an old blanket or tarp over it. This will keep the dust to a minimum. If you are in a coastal region, skip on the cover. This may trap moisture under the cover, contributing to corrosion. Same if your bike will be stored in a windy location, a flapping tap and cause a fair bit of wear. Better to leave it to get dusty and wash it later than have paint or plastic worn on.

    Of course protecting the bike from UV light is another consideration, the tarp does this, or in a shaded spot (there is that spare room in the house again). I have seen riders remove plastic and painted parts storing them inside because the bike itself had to sit on the back porch in the sun, wind and dust.  The more you do in advance, the less you will have to do later.
    Bringing the bike back to life
    When the time has come to get your bike back on the track, trail or street sights all the work you did when you stored it bike will make start up simple and fast.. More importantly no repairs or services will be needed costing riding time and money.
    If fuel was left in the bike, drain the carb float bowl to allow fresh gas from the tank in. Even though the fuel was stabilized, the small volume that is contained in the float bowl will deteriorate much quicker than the much larger volume in the tank. Double check all fluids.  Install the battery if it has one and you removed it. Check the air pressure in the tires. If the bike was not stored clean and protected from dust and such, give it a quick wash and you’re ready to fire it up.

    If you did your job correctly, the motorcycle should come to life. Take an extra few minutes at warm to check for any fluid leaks or strange noises. First start up you may get a bit of non-normal smoke. Corrosion protector you sprayed on the bike during prep, fogging oil in the cylinder. It will burn off in just a few minutes.

    I always like to do a very short oil change interval after the bike has been stored, just as an abundance of caution as well as it gets me a chance to inspect the oil and filters for issues.

    There you go, A Way to prep and store a bike.. No doubt many readers will have their own way that has proven to work for them...if so great, if storage is new to you or you have had issues in the past after storage, consider the process or above.

    The process in this article were used to store the bike in this forum post . As were many others over the years.
     
    Freemotion
    A part on my bike is somewhat of a Gladiator. If it is on my bike it means it has lasted the abuse of riding, racing, the elements, the unknown. It means that it has bested other products in that space and is in some way, superior. My current race bike is a 2018 KTM 300 XC-W Six Days. 
    Everything I run has been carefully chosen and tested in some very harsh conditions. I am proud of, and believe in, the parts I run. I ran FunnelWeb Filters before being sponsored by them. I reached out and asked for the support because I wanted to run the best filter for my riding. They are a sponsor but they did not pay for these thoughts.  
     
    This is my filter after race conditions for ~12hrs and still running strong. The pyramid foam traps the dirt & sand on the top layer leaving air still able to pass. Said another way, it prevents the dirt from penetrating deep into the filter. This keeps maximum airflow and makes it much easier to clean. Dual-layer filters can trap the dirt between layers and that's what makes them very hard to get clean again. It is easier to oil this design & resists dripping. I've tested them against regular filters and the life wasn't even close to Funnelweb filter life. 

    This was side by comparison. Equal time of spinning laps in the super dusty summer. I even ran some dust socks on the twin airs. What I found is that nothing gets past the funnelweb filters. So that's why I run them. I have tested them and seen the performance advantages for myself. 
    I need filters to last for 2 day races. Rarely do I need to change filters between days. Every time you take the filter off your bike some dirt gets in no matter how careful you are. If I don't have to remove it, just another advantage. Not popping this thing off in the pits is one less thing to think about. 
    The filters I use will get soaked, frozen, muddy, the list goes on of what Hard Enduro races demand. Destry Abbott (10x desert racing champ) & his crew run these, Honda team out of Australia runs these too. Hell, if they're good enough for Geocomo Redondi (2018 WORCS champ) they should work for me. It was designed for combating the dust. They are quite popular in Europe and Australia because of how brutal the conditions are.  
    I think of it this way- I expect my filter to still perform even if I lose the airbox cover. I trust the seal of the fwf filters to hold in these conditions. 
    These fwf filters have proven themselves and earned their spot on my bike. 

     

    Kevin from Wiseco
    The piston is one of many wear items in your powersports machine. It may last longer than tires or a chain, but it should still be treated as normal maintenance when the time comes. Here, we go through key tips to help you know when it's time for a refresh.
    The piston in an internal combustion engine is arguably one of the most important components found in the engine. When it comes to high-performance engines used in powersports applications, it is also a component that is regularly replaced and serviced. Knowing when your piston should be replaced and how it wears is key to maintaining a reliable engine. To help you make that decision, we laid out replacement intervals, piston wear, why it’s important to replace the piston, and piston replacement options.

    Piston replacement intervals are typically outlined in your machine’s factory service manual. Using dirt bikes as an example, many manufacturers outline a piston and ring replacement schedule of every six races or 15-30 hours for a four-stroke, depending on the machine. If you’re new to the sport or have never looked at your factory service manual, these service intervals may seem shockingly short. The service intervals are based on the service schedules required to maintain a high-level racer’s machine. Unfortunately, for the average rider, the outlined service intervals commonly end up being conservative.

    The recommended piston service intervals outlined in your manual may be shocking, but the actual required service time depends on many variables that differ by each rider.
    In reality, piston replacement intervals should be established based on how the individual owner rides and maintains their machine. It’s true that forged pistons exhibit greater strength and wear resistance, but the variables of rider and maintenance still apply. Engine displacement, engine make, air filter maintenance, environmental conditions, riding style, and the type of riding the machine is used for will all influence how long the engine should be operated before servicing it. Monitoring the engine’s health through periodic checks such as compression and leak down tests is the best way most riders can appropriately time major service tasks, such as piston and ring replacement. Due to the number of variables that affect engine wear, it is simply not possible to specify a replacement schedule that fits everyone’s needs other than a very conservative schedule.

    Realistically, there are too many variables to establish an official recommended piston replacement time. Sticking to the short time recommended in the manual can be overkill for some, but keeps things on the safe side. (We are not endorsing dry assembly with this photo, it was just mocked up for photo purposes.)
    Piston wear will typically occur in four key areas for both two and four-stroke engines, which include the piston skirt, wrist pin bore, ring grooves, and piston crown. The next time you disassemble your top end, keep an eye out for these wear points.
    Piston Skirt Wear
    Nowadays, on four-stroke engines, the piston skirt is very short and limited to the major and minor thrust faces of the piston. For reference, the thrust faces correspond with the intake and exhaust valve sides of the cylinder head. Two-stroke pistons use the same nomenclature, but feature much longer, more pronounced skirts.

    Piston skirts experience load on the major and minor thrust sides, resulting in wear in those areas.
    Piston skirt wear occurs because of the thrust loading that results from the inherent geometry of the crank mechanism as the engine fires. Peak combustion pressure occurs slightly after top dead center, which causes the piston to thrust into the cylinder wall.
    Skirt wear can be observed both visually and by measuring the skirt’s diameter and referencing it against the diameter outlined in your service manual. Skirt wear will appear as a polished area on the major and minor thrusting faces of the piston.

    Notice the polished-looking wear marks on the forged piston on the left, and the vertical wear marks on two-stroke cast piston on the right. These reflect wear after a substantial amount of run time. The grooves on the two-stroke piston are a potential sign of dust/dirt in the cylinder.
    Your pistons may feature one of a few different types of skirt coating. Wiseco pistons utilize different types of skirt coatings depending on the piston, including ArmorGlide and ArmorFit coatings. These coatings are screen printed on and are applied to remain on the skirt for the life of the piston. You will likely see some wear on the skirt coating after putting time on your piston(s), but if it is worn all the way through the coating, there’s a good chance there’s an underlying issue that needs investigation. Too little clearance, foreign material in the cylinder, and improper cylinder preparation could be causes of excessive skirt wear.

    This piston is equipped with ArmorGlide skirt coating. However, the wear patterns are indicative of the possibility of foreign material, such as dirt, making its way into the cylinder.
    On two-stroke engines, skirt wear can occasionally be heard audibly while the engine is running, which is commonly known as “piston slap”. A rhythmic metallic sound often accompanies a loose or worn piston when the engine idles. What can be heard is the piston rocking back and forth in its bore as it reciprocates.  
    Piston Crown
    Piston crown wear will occur as a result of aggressive or improper tuning, and on four-stroke engines, a damaged or mis-timed valvetrain. Engines operated with a lean mixture at full throttle will see abnormally high combustion temps, which can cause detonation. The results of detonation will be visible on the piston crown as a pitted or eroded surface.

    The pitting in the center is a pretty clear sign of detonation. In many cases, pitting and erosion will be much more evident the leaner the running conditions.
    Piston crown damage due to valvetrain contact will be visible as indentations or cracks near the valve pockets. Valvetrain contact can occur due to valve float caused by excessive RPM or mis-timed valves.

    Notice the half-circles in the valve reliefs. This is a clear sign of valve contact with the piston.
    Ring Groove Wear
    The piston rings move in and out of their grooves because of the ignition of the air/fuel mixture in the combustion chamber. Once the mixture is ignited, the cylinder pressure increases which energizes the compression ring and forces it against the cylinder wall, causing it to slide in its groove.
    On four-stroke engines, the compression ring will transition from seating on the bottom of the ring groove to the top ring groove at the end of the exhaust stroke due to forces of inertia acting on the ring.
     
    Ring movement during operation will eventually wear ring grooves beyond their designed size. Substantial run time can also leave carbon deposits in the ring grooves, affecting ring seal and performance.
    Ring and groove wear can occur due to the sliding and reciprocating motion of the rings and can be exasperated by carbon deposits that accumulate in the ring groove. Ring and groove wear can be qualified by thoroughly cleaning the ring and groove and then measuring each. Most service manuals outline specifications for ring width, groove width, and piston ring to ring groove clearance.
     
    Ring wear can be easily visually observed, but can be confirmed by taking axial height and radial width measurements and comparing them to the original spec.
    Wrist Pin Bore Wear
    Wrist pin bore wear occurs as a result of the loading of the wrist pin joint through inertia and combustion loading. The wrist pin bore will typically wear into an oblong shape. In some engines, wrist pin bore wear will be visible in the top and bottom of the bore. Usually, a portion of the bore will appear burnished or polished. Alternatively, the wrist pin bore can be measured from top to bottom and from side to side. Both measurements can be compared to one another to determine how much the bore has become out of round and to the diameters specified in the service manual.
     
    Wrist pin bores typically wear into a vertical, oval shape due to the pushing and pulling forces of engine operation. Visual inspection can show excessive wear, and a vertical and horizontal diameter measurement can tell you how out of round it is. If it's proving out of round, it's probably time for a replacement.
    The importance of replacing the piston at regular intervals in high-performance powersports engines cannot be overstated. If left unattended, the resulting cumulative wear of the piston will eventually result in a catastrophic and expensive engine failure. Typically, too much time on a piston can lead to gradual and finally complete failure of the skirt in both two and four-stroke engines.
    Between aftermarket suppliers and OEMs, replacement piston options are plentiful and can be overwhelming. The most common upgrade and consideration most riders are faced with is whether or not to move to a forged piston. Forged pistons can be a nice upgrade for many riders because they can offer additional strength and wear resistance over cast pistons.

    Forged pistons achieve greater strength than cast pistons by using different aluminum alloys and manufacturing processes. The forging process for pistons results in finished components that have a tighter molecular structure and grain flow optimized for strength. Comparatively, cast pistons are not cast under high pressures and have molecular structures that are not as tight or organized, which in severe cases, can lead to voids, inclusions, and air pockets.

    Forging pistons results in a better-aligned grain flow and higher tensile strength.
    Read more about how Wiseco forges pistons here.
    Wiseco has been forging pistons in the U.S. for decades and has spent countless hours on research and development to make their forged pistons the option that best combines performance and wear resistance. Still, there is a lifespan to a piston, and the above tips should be used to practice regular maintenance on your machine.
    Okavic
    Whats popping TT Peeps
    About a year ago i decided to tackle a super cheap budget FCR kit, that cost me about 200 bucks if that. Because to be honest i'm not too interested in spending 1000 bucks for a carb. 
    The first most important thing. look for a used carburetor on the Face book market place,Craigslist, Offer up etcetera, generally you'll find many MX bikes that are constantly being parted out. Generally people That are parting out a bike don't really care about part value and will usually sell for cheap, since hey the bikes pretty much rotting in some shed or back yard might as well get rid of it. I've seen all kinds of FCR carbs, that are practically getting thrown away, Me personally i have about 4 FCR carbs, that I picked up for less that 50 bucks a piece. Thats a steal really, $50>$1000.
    1. Carb condition/type 
    From my experience, carbs don't usually require extensive rebuilds, maybe just a simple rebuild kit. That its self only cost about 15 or so bucks, per usual if the piece is covered in an inch thick layer of grime. Its probably not the best bet, of course you're not going to get a brand new part, but hey money talks. nothing more than a can of carb cleaner can help. 
    I've also seen a lot of talk around the forums saying that you'll need a Euro FCR carb (The one with the removable intake bell) to get the ball moving, that is completely false. Japanese mx bikes are alot more common in the U.S. . So you'll come across the fixed intake bell a lot more. These work completely fine don't stress it. Another common misconception i see a lot is FCR size. I'm currently running a FCR 41 bored to 43.5MM and it runs completely fine albeit a little lean... Surprise surprise. Currently running a 42.5 pilot, and a 185 main. 
    Carb sizes varies from maker to maker, my old crf250r had a 40mm carb, the drz can run bigger, no issues at all. One Note Though Stay away from quad carbs, YFZ450R carbs will not fit at all due to the tps system getting in the way.
    2.pieces needed 
    The old DRZ400E had a intake manifold that was made to hold an FCR. The kicker... the damn piece will end up costing as much as the carb if you're able to get on for under 50 bucks. since you're going to have to order through a parts site. Such as Suzuki Parts house. 
    PIPE, INTAKE E3,E28 $13.48
    13111-29F00
    CLAMP, HEAD $3.45
    09402-58208
    CLAMP, CARB 3.45
    0940-58208
    Shipping is gonna be ridiculous, but what ever they have the part, and you don't☹️
    Next you're going to need a FCR bell adapter, you can pick them up on the TT classified page or on ebay. I've seen them go for about $60 or so. I don't think anyone really needs the CNC Adapter, its another 30 bucks. The cast plastic one works fine, you do need to seal it with gasket maker, when installing it to get a complete seal.
    You're finally going to need a new set of cables and a twist Throttle, I tried getting the stock ones to work, but to my luck it didn't work. I got mine for about 35 dollars and i got them in the mail about 3 days later.
    The hot start also comes into account depending how picky you are about your set up. i just plugged mine with an engine bolt. 
    I also recommend getting a Non Vacuum petcock, it only cost about 10 dollars and you don't have to deal with setting up a vacuum nipple.
    And thats about it really my project cost me around 180 dollars and 3 days of down time, also you're gonna have a blast getting the damn thing to fit in the bike but it'll fit. unfortunately i dont have any pictures to show. happy hunting peeps 
    Kevin from Wiseco
    Single and dual compression ring two-stroke pistons have been in service for decades, and since their inception, many have wondered if there are advantages to one or the other. If you have been involved with dirt bikes, jet skis, or snowmobiles long enough, you’ve probably noticed different manufacturers have chosen to use one or two compression ring piston designs for their engines. Furthermore, you may have noticed some aftermarket piston companies offer single ring pistons that replace dual ring pistons and vice versa. So, as a consumer, what do these design differences mean, and which one should you choose?

    Wiseco has been manufacturing two-stroke pistons since 1941. In fact, the company started with two-stroke racing pistons being built in Clyde Wiseman’s garage. There’s no replacement for experience, so we want to take this opportunity to shed some light on the advantages and disadvantages of single and dual compression ring two-stroke pistons designs.
    Compression Ring Function
    We’ll start with a quick review of what a compression ring is designed to do. First and foremost, the compression ring provides a seal that allows the piston to compress the air/fuel mixture as the piston travels upward, then during the combustion event itself, it seals the rapidly expanding hot gases that form during the combustion event. The effectiveness of the compression ring seal, in part, has a significant effect on the power and efficiency of the engine. Should the compression ring lose its ability to seal, the amount of trapped air/fuel mass that will be retained during the compression stroke will be significantly reduced, resulting in less power. Similarly, during the combustion event, a compromised ring seal will allow more gases to leak past the ring, often referred to as blow-by, resulting in reduced power.

    The compression ring, or rings, seals compression so the piston can compress the air/fuel mixture. This plays a critical role in performance, as an improper seal will cause a very poor running condition or not allow the engine to run at all.
    Heat Transfer
    The piston rings play a vital role in transferring heat from the combustion process to the engine's liquid or air cooling systems. During combustion, the piston crown absorbs a portion of the extreme temperatures it is exposed to. If left unregulated, the piston would become so hot that it would melt. Thankfully, the piston rings transfer heat from the piston by connecting the piston to cooler parts of the engine such as the cylinder liner. From the liner, the heat finds its way to the water jacket or to the cooling fins on an air-cooled engine. Engine designers optimize the size, shape, position, and the number of rings to influence how the piston and rings transfer heat.

    In addition to sealing compression, the piston rings play an important role in transferring heat from the piston crown and through the cylinder wall to be dissipated by the cooling system. Otherwise, the piston material would not survive the extreme heat.
    Conformability
    The piston ring’s conformability refers to how well it adheres to the shape of the cylinder bore. The conformability of the ring will have a direct effect on how well it seals the mixture and combustion gases as well as transferring heat to the cylinder liner. Factors that influence a ring’s conformability are shape and thickness. In particular, thicker rings will be less conformable than thinner rings because ring thickness has a significant influence on ring stiffness.

    Thicker rings are generally less conformable, and therefore may not seal compression as effectively. However, too thin of a ring will not transfer heat well enough. It's important to develop a balanced ring that performs both tasks effectively.
    Wiseco’s Research & Development Manager comments, “Racing applications tend to favor single rings for a lower friction penalty. Also, thinner single rings have better conformability to the cylinder and are less susceptible to flutter at high RPM. Even when specified with lower tension, thinner rings can still have good unit pressure which promotes sealing without a high friction penalty.”
    Single Versus Two-Ring Applications
    While many have speculated that certain types of two-stroke powered vehicles—whether it be ATVs, dirt bikes, jet skis, or snowmobiles—need one or two ring pistons, it isn’t so much the specific vehicle application that drives the selection, but more the intended use for the vehicle. The big differentiator is whether the vehicle’s intended use is for racing or not. Two-stroke engines designed and developed for racing typically utilize single ring pistons. When designers optimize an engine for racing and select a single compression ring design, several advantages and disadvantages arise when compared to a two-compression ring design. Let’s take a look at the pros and cons of each.

    A single-ring design is common among Wiseco pistons that are designed for racing and high-performance engines, such as the Racer Elite piston.
    Single Ring Pros:
    ●       Lowest friction design translating to increased power
    ●       Lowest weight design contributing to fast revving
    Single Ring Cons:
    ●       Potentially less longevity due to heat dispersion

    Two-rings designs are popular among riders that prefer added performance durability at the expense of a little performance. However, some big-bore two-stroke applications benefit more overall from a two-ring design.
    Two Ring Pros:
    Improved heat transfer due to the addition of the second ring Engine performance durability due to 2nd ring’s ability to seal if first ring’s seal becomes compromised Two Ring Cons: 
    Increased friction and weight More susceptible to ring flutter at high RPM “Since a good portion of the piston heat is transferred from the piston to the ring and then to the cooler cylinder wall, one advantage of a 2-ring system is that the second ring would provide a second heat transfer path,” adds Dave Fussner on the topic of two-ring designs.

    The last point worth mentioning is that racing piston ring applications are optimized for excellent ring control at high RPM. A condition called “flutter” occurs when a ring becomes unseated from the piston’s ring groove. Flutter occurs around top dead center as the piston transitions from upward motion to downward motion, in part, because the inertia of the ring, which is a function of the ring’s mass, overcomes the gas pressure, pushing the ring against the bottom of the ring groove. When this happens, the ring’s sealing ability is compromised, and engine performance degrades both in terms of performance and durability. Engine designers combat flutter by optimizing the ring's weight so that the ring’s inertia forces cannot induce flutter within the intended RPM range. This is why in many single ring applications the rings are relatively thin.

    Single-ring designs are less susceptible to flutter because there is less ring mass changing direction as the piston begins its return from TDC.
    These are the general and major factors that drive single ring and two-ring designs in two-stroke pistons. The intended use of the vehicle usually drives ring selection, not the vehicle type itself. If you are considering a switch from a single ring to a two ring piston, ultimately, how you intend to use your machine should dictate whether the decision  is sensible or not.


    Freemotion
    I need to win. I have to win. It is an ever-present mindset in everything I do, but especially racing dirtbikes. In order to accomplish this I have to be constantly pushing, striving to get better. Spending most of my seat time on the ragged edge of control and out-of-control means I spend a decent amount of time in the dirt, and spent a whole lot more time there when I was learning to ride a 300 two-stroke this past year.
    My 2018 KTM 300 XC-W Six Days was the first new vehicle I've ever had of any sort. Because this bike meant a lot to me, and I could not afford a new pipe every ride, I went looking for protection, for armor.
                
    *A Mykel Horner Photo
    I came across an Emperor Racing skid plate and pipe-guard combo at a distributor and new instantly it was what I needed on my bike if I was going to keep it Ready to Race. Before I could purchase it, it was purchased at retail for me for Christmas by my girlfriend.
    I had no idea the history and passion behind Emperor Racing until I moved to Colorado and started racing for Emperor Racing as a fully supported rider. I already knew the products were awesome and racing under Emperor I got to work with Steve and really get to know the Canadian company.
                                           
    At the Helm, a Mechanical Designer by trade, rider by blood; Steve Vander Helm, proud Canadian. Talk about passion for our sport. Rider through and through, and has the professional skills to conceptualize, develop, and produce some premier dirtbike protection parts.
                  
     
    They machine very high-grade, high tolerance type pieces to not only look killer, but perform even better. Steve started doing mechanical design for the elevator industry and later for the heavy steel industry designing dump truck boxes, low bed heavy-haul trailers and precision excavator attachments. From there he designed parts for most of the elevators you see and use today. He saw the successes of his designs and the company owning patents of his design, but never saw the value returned to him as the designer. Eventually Steve concluded that he was better off solo. But what would he design? Steve was then, and is now, an avid rider. He noticed these riders all getting new bikes but could not get guarding products for them in a timely manner. From there; the idea of Scorpion Racing is born. 
    Steve figured he spends all his time riding and racing, saw the demand for the product at his races and knew he had the skills to bring it to life. So he decided to start a company called Scorpion Racing that made premium, rock-solid dirt bike parts because he was already making custom plates for all his buds, but custom-only was not going to be profitable at scale so he started producing the first generation light skid models in 2005. Soon after that was the 1st gen rad Rad guard.
                                             
                   2007 Model Lightweight Guard for WR450
    Fast forward to 2008, the market needs a heavy duty model. Riders have been asking and Steve had been prototyping some models and releases the Heavy Duty Skid Guard combo, under the Scorpion Racing name, that is the root of his flagship product today.
                                               
                 *2008 HD Skid Plate for KTM & Husky 
    In 2012, Pirelli tires forced then Scorpion Racing off their name citing they already had that brand established. They then re-branded as Emperor Racing as it became a situation where whoever had the most money to throw at lawyers was going to win that one. Steve made the smart business decision to not take on the tire giant as he was out-gunned.
    Ever since Steve’s inception as Scorpion Racing back in 2005 his products have always been created through extreme testing and rider input. He takes that feedback and uses that mold his next models or improvements. That’s huge. And I think lost on a lot of companies nowadays. Most other companies are so full steam ahead with their vision they might have stopped to consider the consumer’s needs.
    The flagship product today, the Pipe Guard Skid Plate is a beautiful piece of machining. Start to finish, end to end, you can tell it’s something made by someone with a lot of pride in what they do. Beveled edges, high-grad Alu, all metric hardware, the list goes on. The quality and craftsmanship is very obvious with handling these plates. On the bike is even better. Being all aluminum they have a UHMW plastic "Slip Liner/ Link Guard" easily bolted to the plate that does exactly what the name suggests; help you skate over obstacles easily and protect your linkage, win-win.
    *These products are available for most recent & current model year 250 & 300 two-strokes, and the 250, 350, 450 model four-strokes

    This plate is the real deal. I can now practice here in The Rockies with confidence. Bashing rocks and logs 10 miles away from the truck down some gnarly single-track can lead to some stranded-type issues if things go sideways. I think broken clutch covers, crushed stator, mechanical DNF’s, etc. are all severely reduced, if not eliminated altogether by having this grade of protection.
    It mounts firmly to frame with a secondary plate/bracket that stops the force of impacts from being transferred to the exhaust. Snug-fit hardware throughout makes install super easy. No holding bolts in place while trying to find them with a bolt. Oil changes can be done without removing the plate.
    The rad guard of today morphed from a Scorpion two-piece design to a one-piece, brace & guard that protects the radiators very well. The biggest issues with a rad guard are the limits riders want: We do not want a width increase, height increase, want to be able to mount aftermarket fans, nothing on the back, easy mounting, light. The Emperor Rad Guard does all that. I have use it and crashed with it plenty. It does its job.
               
     
    A product’s warranty is a great way to gauge how the company feels about their product, especially those that make wear parts. Steve offers a 1 year warranty on his products and stands by that warranty. I know, I've tested it. 
    I had some riding buds in town soon after moving to Colorado. We went for a ride on some trails that were new to all of us- that’s always fun- new trail. We were moving through some double-track on the lookout for a trail. I was leading and came up to a Y in the road about 35-40mph. I was slightly entering the left-hand trail when noticed we needed to go right. So I pulled across the grass ‘median’ and caught a rock hiding in the grass.
    The plate acted as a crumple zone and transferred the impact through my pipe and bent it at the weakest point, the joint. I was able to ride the rest of the day without limitation.
           
    I had to cover shipping both ways but Steve replaced the guard at no charge and replaced a brand new guard for the cost of shipping. I am only the 2nd person that needed a plate warrantied. It was an easy process and hope to not need to warranty another.
    The story here is a cool one. A very smart and production-capable rider started making great products 13 years ago. His love for the sport makes him constantly striving to innovate and stay on top of what the consumer wants in premium bike protection. I think its some of the best money spent as I would surely have cracked cases, an exhaust flange, something by now learning splat and crossing techniques for racing enduro.
                                             
    People often see the skid plate and rule it out for weight or frame flex reasons. It weighs 7lbs and the weight is sprung. I think you have to ride at a pro or season pro level to feel stuff like that, but perhaps not. For me it’s saved my race, my day, my bike. Until I manage to stay off the ground and clear obstacles I’ll likely be riding with Emperor Protection.
    If you’re interested in protecting your bike and getting that peace of mind I would encourage you to look to at EmperorRacing.com. They are in full support of our sport, put their money where their mouth is, rider founded, rider ran and they make some damn good products and I am proud to ride for them.

    We will be doing write up and review on the skid plate and the rad guard separately. Long ago, when installing the first skid plate on my bike I decided to write up a how-to to do the install. If you need any more help you can refer to that walk-through here.
     
    Bryan Bosch
    Every industry has iconic brands that pretty much everyone knows about. If you ask a rider to name a leading dirt bike exhaust brand, they’ll likely say FMF. Ask the same about handlebars and you’ll probably hear Renthal or Pro Taper.
    I also encounter brands that make really good stuff, but for any number of reasons, just aren't well known. One such brand is USWE Sports, a Swedish manufacturer of high-quality, high-performance hydration packs for the moto, mtb, snow, and running sports. Interestingly enough, you just might have experienced a USWE product, as they made packs for popular moto brands such as Leatt, MSR, and Fly Racing. 


    Action Pack, NOT Backpack!
    So, what's the "secret sauce" that USWE bakes into its action packs that makes them especially good for us dirt bike guys? At the heart of USWE hydration packs is NDM (No Dancing Monkey ?) technology. It’s a goofy visual for their award winning, patented 4-point suspension harness and buckle system that allows the pack to form fit very snug against your body, virtually stopping pack bounce in rough terrain, while maintaining comfort, freedom-of-movement & breathing capacity. This sounds like a simple enough task, but it’s taken many iterations and thousands of sweaty riding hours to get USWE action packs to this level of performance. Even the bladder itself has design elements that work in concert with their patented harness to minimize and control pack movement. Here's a short video that demonstrates NDM tech (harness demo @ 1:12).
     
    From the Swedish Horse's Mouth
    Recently I caught up with Karl-Johan Engdahl, USWE Co-Founder and Business Development & Marketing Director for a few questions:
    TT: The USWE name... What’s the backstory there? Something interesting in Swedish?
    TT: USWE has been in the hydration pack game for over a decade. What accomplishment are you guys most proud of?
    TT: Amazing riders like Colton Haaker, Cody Webb, Taylor Robert, Billy Bolt, and Alfredo Gomez are USWE sponsored. How much of a role do they play in shaping USWE product development and design?
    TT: At least in the US, you can walk into most big box stores and pick up a hydration pack for pretty cheap. Why are some riders still spending more money on USWE hydration packs?
    TT: Where can we expect to see USWE this year in terms of events & series?
    TT: The floor is yours Karl. What else do you want riders to know about USWE and its products?


    USWE Athlete, Billy Bolt @billybolt57
    USWE wants to get their action packs in the hands of riders because they're confident that once tried, they'll be a convert. Stay tuned for a USWE product giveaway that we'll be hosting before the end of the year. They'll be giving away a bunch of action packs to lucky Thumpertalk Community Members! Maybe you'll be one of them? ?
     
    USWE 2019 Action Pack Line-Up
    NDM HARNESS - INCL. IN ALL USWE ACTION PACKS (EX. H1)
    Race Suspension - NDMTM patented technology 4-point stretch harness that supports max breathing capacity and freedom to move Solo-buckle secure system makes it easy to take on/off the pack even while wearing gloves Ergonomic shoulder and chest straps with dual-loop Velcro multi size function 100% bounce free in action
      ZULO HIPBELT SERIES - NEW
    Available on-line end of October. In stores sometime December 2018.


    ZULO 2
    SUPERLIGHT RACE HYDRATION HIPBELT
    1.0L/35oz Hydrapak EliteTM hydration bladder Magnet tube clip 2L total cargo capacity Organizer pocket: keeps your tools and gear in safe position Size: Multi size adjustable: S-XL, Adult Light mesh back panel LED-light attachment points: Front and back Colors: Carbon Black, Crazy Yellow ZULO 4
    Will be announced soon..
     
    OUTLANDER PACK SERIES
    NEW! Available ONLINE end of October. In STORES during December 2018. Will be our Moto head product. Single color options.

    OUTLANDER 2
    SUPERLIGHT RACE HYDRATION PACK
    1.5L/50oz Hydrapak EliteTM hydration bladder 2L total cargo capacity Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 38cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult High-ventilated shoulder straps with foam pads Light mesh back panel LED-light attachment points: Front and back Brace compatible Colors: Carbon Black, Crazy Yellow
     
    OUTLANDER 3
    RACE HYDRATION PACK W. ON/OFF ORGANIZER
    1.5L/50oz Hydrapak EliteTM hydration bladder 2 + 1L (3L) total cargo capacity On/Off organizer pocket Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 38cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult High-ventilated shoulder straps with foam pads Light mesh back panel LED-light attachment points: Front and back Brace compatible Colors: Carbon Black, Crazy Yellow OUTLANDER 4
    HARD ENDURO HYDRATION PACK W. LARGE HYDRATION CAP.
    2,5L/85oz Hydrapak Shape-ShiftTM hydration bladder (open baffle 3,0L/100oz) w. Plag-n-Play 4L total cargo capacity Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 38cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult High-ventilated shoulder straps with foam pads Light mesh back panel Brace compatible Colors: Carbon Black, Crazy Yellow OUTLANDER 9
    ADVENTURE HYDRATION PACK W. LARGE HYDRATION CAP.
    3,0L/100oz Hydrapak EliteTM hydration bladder Bladder compression sleeve: keeps bladder in fixed position 9L total cargo capacity Organizer pocket: keeps your tools and gear in safe position Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 45cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult High-ventilated shoulder straps with foam pads Light mesh back panel Brace compatible Colors: Carbon Black, Crazy Yellow
      RANGER PACK SERIES
    Available NOW
    RANGER 3
    RACE HYDRATION PACK W. ON/OFF ORGANIZER
    1.5L/50oz Hydrapak EliteTM hydration bladder w. Plug-n-Play 2 + 1L (3L) total cargo capacity On/Off organizer pocket Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 38cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult Light mesh back panel Brace compatible Colors: Black/Black, Orange/Black, Blue/Black RANGER 4
    HARD ENDURO HYDRATION PACK W. LARGE HYDRATION CAP. 2,5L/85oz Hydrapak Shape-ShiftTM hydration bladder (open baffle 3,0L/100oz) w. Plug-n-Play 4L total cargo capacity Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 38cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult Light mesh back panel Brace compatible Colors: Black/Black, Orange/Black, Blue/Black
    Giving the USWE Ranger 9 a shot - Withlacoochee National Forest, FL
     
    RANGER 9
    ADVENTURE HYDRATION PACK W. LARGE HYDRATION CAP.
    2,5L/85oz Hydrapak EliteTM hydration bladder w. Plug-n-Play Bladder compression sleeve: keeps bladder in fixed position 9L total cargo capacity Organizer pocket: keeps your tools and gear in safe position Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 45cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult Light mesh back panel Brace compatible Colors: Black/Black, Orange/Black, Blue/Black
      PATRIOT 9L PACK
    Available NOW


     
    PATRIOT 9
    ADVENTURE HYDRATION PACK W. LARGE HYDRATION CAP., QUICK STASH
    POCKET & ARMOR ATTACHMENT
    2,5L/85oz Hydrapak Shape-ShiftTM hydration bladder (open baffle 3,0L/100oz) w. Plug-n-Play Bladder compression sleeve: keeps bladder in fixed position 9L total cargo capacity Organizer pocket: keeps your tools and gear in safe position Quick stash pocket and attachment points for gear Water resistant media pocket (W 8.5cm x D 16cm) Dim: H: 45cm x W: 29cm x 8 cm Size: Multi size adjustable: M-XL, Adult Light mesh back panel Brace compatible Colors: Camo, Chili Red
      TANKER 16L PACK
    Available NOW

     
    TANKER 16
    ADVENTURE PACK – HYDRATION COMPATIBLE
    ▪ Hydration compatible
    ▪ 16L total cargo capacity
    ▪ Organizer pocket: keeps your tools and gear in safe position
    ▪ Water resistant media pocket (W 8.5cm x D 16cm)
    ▪ Dim: H: 50cm x W: 29cm x 8 cm
    ▪ Size: Multi size adjustable: M-XL, Adult
    ▪ Light mesh back panel
    ▪ Brace compatible
    ▪ Colors: Black/Black, Orange/Black, Blue/Black


    XC PACK SERIES
    Available NOW

     

    XC ELITE
    LIGHT HYDRATION PACK
    ▪ 1.5L/50oz Hydrapak EliteTM hydration bladder
    ▪ 2L total cargo capacity
    ▪ Dim: H: 38cm x W: 29cm x 8 cm
    ▪ Size: Multi size adjustable: M-XL, Adult
    ▪ Light mesh back panel
    ▪ Brace compatible
    ▪ Colors: Black/Red
    XC / XC JUNIOR
    LIGHT HYDRATION PACK W. DISPOSABLE HYDRATION BLADDERS
    ▪ 1.5L/50oz Disposable hydration bladder
    ▪ 2L total cargo capacity
    ▪ Dim: H: 38cm x W: 29cm x 8 cm
    ▪ Size: Multi size adjustable: M-XL, Adult
    ▪ Light mesh back panel
    ▪ Brace compatible
    ▪ Colors: Black/Red


    H1 RACE HARNESS
    Available NOW


     
    H1 RACE HARNESS
    SUPERLIGHT HYDRATION HARNESS (MX & ENDURO)
    ▪ 0.5L/18oz Disposable hydration bladder
    ▪ Size: Multi size adjustable: M-XL, Adult
    ▪ Full-mesh body for optimal weight and ventilation
    ▪ Velcro stretch straps that supports max breathing capacity and freedom to move
    ▪ NOT brace compatible
    ▪ Colors: Black/Red
     
    You can learn more about USWE Action Packs HERE.



    Bryan Bosch
    Updated 01/18/2019 (added links to various other owner reviews)
    Recently, American Honda invited me out to Packwood, Washington to ride the 2019 CRF450L, one of the most hotly anticipated new motorcycle model releases in recent memory. I’ve been reading posts for years from riders begging the Japanese manufacturers to bring them a modern, performance oriented dual sport motorcycle, and I too was happy when I learned that Honda had stepped up. Increased competition means better bikes and more choices for us riders! 
    Despite our stickers all around, Honda didn't let me keep this 450L .
    Our 106 mile test loop included a section of country highway, twisting back roads, gravel forest service roads, fast & flowing double track, and epic technical single track. Weather was cool & damp and we rode elevations from approximately 1,000 to 5,300ft.

    106 Miles of Dual Sport happiness!
    Our test bikes were stock except for the installation of Dunlop D606 DOT tires, suspension clicker adjustments for the conditions being ridden, and sag adjustment as necessary. I’m a 49 year old, off-road focused dual sport rider with 35+ years of recreational riding experience. I’m not always the fastest in the group, but I rarely bring up the back either.
    What Type of Rider is the CRF450L Most Suited To?
    I think Honda was pretty accurate by framing the 450L as a trail-to-trail, performance dual sport. No question that it leans more towards the true dirt side of the spectrum, but with enough comfort and refinement baked in to make your ride to the trailhead and connecting trails enjoyable. It’s docile enough for a developing rider with decent throttle & clutch skills to enjoy on mild to moderate single track, but still has the ability to satisfy accomplished riders who like to push in more demanding conditions. Our test group included a few very fast riders (including Johnny Campbell) and no one said that the bike was holding them back much, if at all. I certainly didn’t feel limited when pushing anywhere. What the 450L is not is a light-duty trail machine designed more for traveling distance on graded dirt roads or highway. It very well might just do that, but it certainly isn’t one of its core competencies, nor would it be my first choice for such. 
    Does the CRF450L Have More Than the Rumored 25hp?
    Oh, heck ya! Honda didn’t provide actual dyno numbers, but they estimated the 450L to be in the mid 40hp range. My butt dyno says that’s in the ballpark. It has enough oomph to keep things exciting, but not so much that you can get in trouble quickly when you're tired. No question that fire-breathing power can be fun, but for a long day in the saddle, the 450L power didn’t unnecessarily wear me out.

    Yeah, the CRF450L will wheelie. Photo by Drew Ruiz
    Throttle response is crisp and power delivery is super smooth & completely linear to its 10,000 rpm redline (5th gear). Roll-on power lower in the RPM range is initially a tad soft, something fairly common with emission controlled dual sports. However, a downshift or handful of clutch produces pretty much instant boost. To be fair, I’m a bit of a short shifter, so riding the bike in lower gear at a little higher RPM kept the motor in the sweet spot of the power curve.
    The 450L has a 12% heavier crank and a heavier clutch basket than the 2019 CRF450R, making the power very tractable and resistant to stalling. The 450L put the power down incredibly well, making for excellent traction despite running a little higher tire pressure than I prefer (15psi front & back). I did manage to stall the bike a few times, but I blame that more on my left hand and gear selection than the bike.
    I asked Honda if the ECU could be remapped, but they were a little hesitant to dive into that pool. And, I understand why. I pressed them just a bit and they did say that the ECU can compensate to some degree, such as for an aftermarket exhaust and that an ECU remap may be possible. You’ll have to form your own conclusions.
    Is the CRF450L Showa Suspension Any Good?
    The 2019 CRF450L has the same, fully-adjustable Showa 49mm coil spring fork & Pro-link shock as its 450R & 450X cousins, but specifically tuned for performance dual sport riding. It’s sprung for around an 180lb. rider (fully geared) and Honda took into consideration that some riders will be adding additional weight with the installation of a rack or soft luggage and cargo. Since we're talking about cargo, the aluminium sub-frame extends the full length of the rear fender and while Honda didn't quote us a weight limit, I rode at least a 175lb. rider back to his bike. I suspect that it will handle pretty much whatever most riders will need to carry.
    Fully geared up, including a full hydration bladder and trail incidentals, I’m right at 210lbs.. Despite being 30lbs. over the ideal spring weight, I thought that the 450L suspension worked incredibly well. Riding over washboard forest service roads at a pretty good clip, I took note of how planted and composed the bike remained. On the trails it soaked up rocks and roots well, and even square edged hits didn’t transmit harshly though the handlebars or upset the chassis. I also took note of how well the bike handled sections of stutter bumps, something that does a good job of exposing suspension weaknesses.

    Fun fast & flowing section of Pac NW single track. Photo by Drew Ruiz
    On one of the higher-speed dirt roads, climbing up to a decommissioned fire outlook (Burley Mountain) were some awesome roller humps. I didn’t slow down for one in particular and when I was just about to lift off, I noticed that I was going to land in a dip on the other side. I figured that I was going to bottom out both ends, but to my surprise, the suspension fully soaked up the hit! Suffice to say, out-of-the box, I think that the 450L Showa suspension is highly effective, forgiving, and can only get better if sprung and valved for a rider’s weight, conditions, and skill level.
    Does the CRF450L Feel Heavy?
    I guess that depends upon what you’re use to. It feels noticeably lighter than my KTM 690 Enduro R, but not too much heavier than a KTM 450 EXC that I used to own or a KTM 450 XC-W that I rode this summer while in Colorado. Nowhere on the trail did I feel like I was wrestling a beast or fighting against the bike.
    The 450L has a slightly longer wheelbase than the 450X for added stability on the road, but it still dropped into turns willingly and steered accurately. It didn’t take long for me to build confidence in the bike’s handling, trusting the front-end to stick and to start brake sliding into corners. The 450L is a very predictable handler, confidence inspiring, and fun to ride. I don't think it took more than an hour on the bike to feel right at home.
    For those looking to save every ounce of weight, the biggest savings will probably come from an aftermarket exhaust, as the stainless silencer includes a catalytic converter to comply with emissions. It already comes with a light-weight Lithium battery, so there simply isn’t unnecessary weight just hanging around. Me? I wouldn't touch the stock exhaust and I'll cover why later in my review.
    How’s the Gas Mileage?
    The specs have been out on the 2019 CRF450L for a while now, so many have already shared their concerns about its 2 gallon fuel capacity. Obviously, mpg is going to vary by how you ride the bike and the conditions being ridden. Honda quoted an average mpg for mixed conditions of 50, so right at 100 miles per tank. While the digital dashboard doesn’t have a traditional fuel gauge that displays what you have left, it does tell you how much fuel you’ve consumed, how far you’ve ridden, and your average mpg for both trip A and trip B settings.
    Admittedly, when we got back from the ride, I was pretty tired, soaked to the undies, and ready for a hot shower. So, I forgot to check how much fuel the bike had burned!  What I do know is that approximately 2 gallons took me through 106 miles of epic Pac NW mountain roads & trails, I didn’t ride with fuel economy in mind, and I absolutely got my fill of riding that day.
    For some riders, 2 gallons won’t be enough, so they’ll have to look to the aftermarket for a solution. I recently talked to Chris Harden, the GM at IMS Products and he confirmed that they’ll have an extra capacity tank ready in about 6 weeks. He further said that it should be between 3 to 3.2 gallons in capacity, have a screw cap and dry break option, and colors of black and natural. IMS will be sending me a 450L  tank to check out, so I’ll post up some pictures when it arrives. Curious to see where they found the extra room.
    How’s the Gear Box & Clutch?
    The 2019 CRF450L features a 6 speed wide-ratio transmission with fairly low 1st gear for tight conditions and a 6th with enough legs for highway speeds.
    1st gear is usable in very slow, technical conditions, but the bike can feel a little jumpy at times because the fuel mapping is somewhat sensitive. If you have good throttle and clutch control it’s not a big deal, it's just something that I noticed while getting to know the bike. In terms of gear spacing, I think Honda did a good job with the ratios, not noticing any unexpected or annoying gaps.
    I was able to get the 450L up to 80 mph on a longer back road (closed for safety of course ) and there was still more speed to be had. I don’t see an issue with the bike cruising at 65-70, 75ish for shorter runs, and 80-85ish when passing. The 450L doesn't have a tachometer, so I can’t say what the bike was turning at different speeds. But for the vast majority of traveling speeds, the bike isn't rapping out or feeling like you’re squeezing. I asked Honda for the 450L transmission gear ratios, but I'm still waiting on them. I'll add them here when they come in. Honda did say that at 65 mph, the engine is turning in the 6,000 rpm range.  ****Updated 09/25/18: Actual Gear Ratios***
    Overall, I really enjoyed the 450L gearbox.  It’s very smooth to operate, it’s quiet, and despite being on an unfamiliar bike, I didn’t have a mis-shift the entire day. I wish my 690 transmission was this good honestly. As a point of reference, I wear size 10 boots and getting under the shift lever was no problem.
    I was initially a little disappointed to see that the 450L doesn't have a hydraulic clutch, but I found lever pull to be smooth and light as far as cables go. The clutch perch has a manual adjuster wheel that works well, even with gloves on. We didn't ride hard enduro conditions, but there were sections of technical single track that required more aggressive clutching and I didn't notice any fading or chatter.  Both control levers are on the shorty side, something I prefer and both were effective with two fingers.
    How are the CRF450L Brakes?
    The 450L has a 260mm cross-drilled wave rotor up front that is squeezed by a Nissan 2-piston caliper. To meet DOT requirements, the front rotor is a thicker and the hydraulic reservoir carries more fluid. At the rear is a matching 240mm rotor and single piston caliper. No ABS is present at either end.
    The front brake has good initial bite without being too grabby. I found it easy to modulate, fade free, and plenty powerful. The back brake was a little grabby, but I was just using it how I ride my 690. Once I adjusted my inputs it was fine and in short order I was brake sliding into corners like normal. The brakes were also able to haul the bike down from 70-80 mph on wet back roads with no drama.
    Is the Seat Comfy?   
    It’s a slim profile dirt bike seat with fairly firm foam that, for its intended purpose, it's fine. Compared to the range of MX and Enduro bikes that I've ridden, it's one of the more comfortable, but it's not XR650L comfortable for example. Surprisingly, I didn’t start to get uncomfortable until the last hour, hour and a half of the day, but we also rode a decent amount of stand-up terrain. I’m sure that the aftermarket will bring 450L comfort oriented seats to the market very soon. I did like the seat cover; it has good grip, even when riding in wet conditions.
    Is the CRF450L Tall?
    At 5’ 10” with a 32” inseam, I’m pretty close to reaching the ground with both feet flat. Considering all the different dirt bikes, dual sports, and ADV bikes that I’ve ridden, no, I don’t think that 450L is tall. It has the same amount of suspension travel as the CRF450R and X, but it’s a little heavier, so it sits slightly lower in the stroke.
    For the first couple of road miles, I thought that the seat to peg room was going to feel a bit cramped, but that thought quickly disappeared as the miles increased. One thing that I did like was how the textured radiator shrouds give you more traction at the knees and their profile created the perfect "pocket" when scooching up on the tank for sit down corners. If Honda made the textured areas of the radiator shrouds out of a little softer (grippier) material, they'd be even better.
    Are the Service Intervals Reasonable?
    For 2019 CRF450L, Honda specifies 600 mile oil change intervals and 1,800 mile valve checks. For the intended purpose of this bike, I don't think that's unreasonable. For oil, that's a half a dozen rides just like our test loop and 18 of the same for valves. At least for me, that's a lot of run relative to the time and maintenance costs. And, Honda is known to be conservative with their recommendations, so personally I wouldn't sweat going 10-15% over those miles occasionally. 2019 CRF450L service interval matrix
    In terms of long-term reliability, there's no way I can tell you from a one day ride. The best indicators will be how later gen 450X models have held up and to a lesser extent, the 450R. Few would argue that Honda doesn't have a reputation for quality and the warranty on the 2019 CRF450L seems to back that up. It comes with a 1 year factory warranty, but the same can be extended out to 5 years total for an additional cost. You can even buy just an extra year or an extra 3, so flexibility has been built into the program. I do know that the 450L uses a 3-ring piston that will extend top-end life at a fractional performance cost pretty much no riders will notice. This just makes sense for the application.

    Illustration: American Honda
    Is the LED Headlight Effective?
    We didn’t get an opportunity to night ride, so we improvised and pushed a 450L into a field on the edge the hotel, pointing the headlight into the woods.

    The cutoff height increases with a rider on the bike. Pics taken with no rider. Photo by El Jefe of CDSR.
    I think that the CRF450L headlight would do a good job for a night time cruise on back roads at legal-ish speeds and no question that it would get you off the trails if you got caught out after dark. But if you really want to trail ride at night, get something helmet mounted.
    Anything That I Didn't Like About the 2019 CRF450L?
    The clutch lever perch has an internal switch that requires the lever to be pulled fully against the grip in order to restart the bike. It wasn't a huge deal for me, but something that I noticed when I flamed out and tried to get the bike lit quickly with the magic button. I know that this was a point of feedback from some of the very fast riders in our group to Honda engineers who eagerly solicited feedback after the ride. 
    I also don't like that there is no back-up kickstarter for a dual sport that is designed to get deep into the woods. I did confirm with Honda that the new engine cases do not allow for one to be installed retro.  My KTM 690 shares the same design and in the last 1.5 years of ownership it's been no issue. Honda has a pretty solid reputation for reliability, so I think that this falls under the premise that all things are possible, but not all things are likely. For those that Murphy's Law seems to follow, there are good portable jump starters that are easily carried in small packs and "smart" batteries that protect themselves from over-discharge such as the Antigravity "Re-Start"  Lithium battery.
    At least for me, the horn button is too easy to hit when you're looking for the turn signal switch. The button is above and sticks out past the signal switch below it, so I ended up honking at the rider in front of me a few times accidentally. But, by the end of the day, I had adapted. The turn signal switch gets used far more than the horn, so I think there's room for improvement ergonomically.
    What Really Stood Out About the CRF450L? 
    Probably how smooth, refined, and quiet this bike is, despite it being so performance oriented and capable. The combination of rubber dampened sprockets, chain guide, roller & slider materials, urethane filled swingarm, and foam-backed plastic ignition, clutch, and primary sprocket covers help to make this the most refined, low vibration, and quiet street legal dirt bike that I've ridden. Add in a quiet exhaust note and the 450L is pretty stealthy. After a full day of riding, I had a ton of fun, never felt held back, but I really appreciated the lack of mental & physical wear that loud and more raw bikes have. Loud pipes don't save lives, but they do tick off others recreating in or living by the areas we ride.

    Quiet, refined, & stealthy doesn't have to kill the thrill. Photos: American Honda
    Honorable mention: The LED turn signals double as running lights and can be bent 90°, snapping back into operating position without damage. It's a little detail, but a smart and appreciated one. On a bike like this, conventional signals on the rear would last days if not hours.
    Would I Personally Buy a 2019 CRF450L? 
    Absolutely. Since I left the event, I've been thinking hard about putting a 450L in my garage. I really like this bike a lot. I've not been on a Honda since mid 2000 and they brought their guns to the performance dual sport market with the 2019 CRF450L. Glad to see Honda shaking up the segment and riders are the winners. I wonder who will fire back next? 

    Read more reviews on the 2019 Honda CRF450L
    Questions & Comments?
    I could probably write more about the 2019 CRF450L, but I think that I covered the important stuff and the things that stood out to me. But, the cool thing about ThumperTalk is the conversation. If I didn't do a good job explaining something or worse, completely glossed over something important to you, DO post your question(s) in the comments section below. If I know, I'll answer. If I don't, I'll reach out to the Honda folks  and see if I can get an answer. The 450L isn't cheap, so if I can help you make the right decision, my mission will have been accomplished.  Also, you can find a several galleries with lots of photos of the 2019 CRF450L in action, as well as close-ups and tech/service info HERE.
     
    Bryan Bosch, ThumperTalk.com

    #crf450L #ridered #dualsport #blessed #grateful
    Billy@JEPistons
    Whether you're racing or looking for increased performance out on the trail, there are a plethora of performance upgrades to consider to increase the power of your machine. Piston manufacturers like JE Pistons offer high compression piston options for many applications, but there are important merits and drawbacks you should consider when deciding if a high compression piston is right for your application. To better understand, we’ll take a look at what increasing compression ratio does, what effects this has on the engine, detail how high compression pistons are made, and provide a high-level overview of which applications may benefit from utilizing a high compression piston.

    Bumping up the compression in your motor should be an informed decision. It's important to first understand what effects high-compression has, the anatomy of a high-comp piston, and what applications typically benefit most.
    Let’s start with a quick review of what the compression ratio is, then we’ll get into how it affects performance. The compression ratio compares the volume above the piston at bottom dead center (BDC) to the volume above the piston at top dead center (TDC). Shown below is the mathematical equation that defines compression ratio:

    The swept volume is the volume that the piston displaces as it moves through its stroke. The clearance volume is the volume of the combustion chamber when the piston is at top dead center (TDC). There are multiple different dimensions to take into account when calculating clearance volume, but for the sake of keeping this introductory, this is the formula as an overview. When alterations to the compression ratio are made, the clearance volume is reduced, resulting in a higher ratio. Reductions in clearance volume are typically achieved by modifying the geometry of the piston crown so that it occupies more combustion chamber space.
     
    Swept volume is the volume displaced as the piston moves through the stroke, and clearance volume is the volume of the combustion chamber with the piston at top dead center.
    How does an increased compression ratio affect engine performance? To understand how increasing the compression ratio affects performance, we have to start with understanding what happens to the fuel/air mixture on the compression stroke. During the compression stroke, the fuel/air mixture is compressed, and due to thermodynamic laws, the compressed mixture increases in temperature and pressure. Comparatively, increasing the compression ratio over that of a stock ratio, the fuel/air mixture is compressed more, resulting in increased temperature and pressure before the combustion event.
    The resulting power that can be extracted from the combustion event is heavily dependent on the temperature and pressure of the fuel/air mixture prior to combustion. The temperature and pressure of the mixture before combustion influences the peak cylinder pressure during combustion, as well as the peak in-cylinder temperature. For thermodynamic reasons, increases in peak cylinder pressure and temperature during combustion will result in increased mechanical efficiency, the extraction of more work, and increased power during the power stroke. In summary, the more the fuel/air mixture can be compressed before combustion, the more energy can be extracted from it.

    Higher compression allows for a larger amount of fuel/air mixture to be successfully combusted, ultimately resulting in more power produced during the power stroke.
    However, there are limits to how much the mixture can be compressed prior to combustion. If the temperature of the mixture increases too much before the firing of the spark plug, the mixture can auto ignite, which is often referred to as pre-ignition. Another detrimental combustion condition that can also occur is called detonation. Detonation occurs when end gases spontaneously ignite after the spark plug fires. Both conditions put severe mechanical stress on the engine because cylinder pressures far exceed what the engine was designed for, which can damage top end components and negatively affect performance.
     
    Detonation and pre-ignition can spike cylinder pressure and temperature, causing damage. Common signs of these conditions include pitting on the piston crown.
    Now that there is an understanding of what changes occur during the combustion event to deliver increased power, we can look at what other effects these changes have on the engine. Since cylinder pressure is increased, more stress is put on the engine. The amount of additional stress that is introduced is largely dependent on the overall engine setup. Since combustion temperatures increase with increased compression ratio, the engine must also dissipate more heat. If not adequately managed, increased temperatures can reduce the lifespan of top-end components.
     
    JE's EN plating is a surface treatment that can protect the piston crown and ring grooves from potential damage caused by high cylinder pressure and temperature. EN can be an asset for longevity in a high-compression race build.
    Often, additional modifications can be made to help mitigate the side effects of increasing the compression ratio. To help reduce the risk of pre-ignition and detonation, using a fuel with a higher octane rating can be advantageous. Altering the combustion event by increasing the amount of fuel (richening the mixture) and changing the ignition timing can also help. Cooling system improvement can be an effective way to combat the additional heat generated by the combustion event. Selecting larger or more efficient radiators, oil coolers, and water pumps are all options that can be explored. Equipping the engine with a high-performance clutch can help reduce clutch slip and wear which can occur due to the increased power.

    High-level race team machines are great examples of additional modifications made to compensate for increased stress race engines encounter. Mods include things like larger radiators, race fuel, custom mapping, and performance clutch components.
    Let’s take a quick look at what considerations are made when designing a high compression piston. Typically, high compression pistons are made by adding dome volume to the piston crown, which reduces the clearance volume at TDC. In some cases, this is difficult to do depending on the combustion chamber shape, size of the valves, or the amount of valve lift. When designing the dome, it is essential to opt for smooth dome designs. Smooth domes as opposed to more aggressively ridged designs are preferred because the latter can result in hot spots on the piston crown, which can lead to pre-ignition. Another common design option is to increase the compression distance, which is the distance from the center of the wrist pin bore to the crown of the piston. In this approach, the squish clearance, which is the clearance between the piston and head, is reduced.
     
     
    Higher compression is commonly achieved by increasing dome volume while retaining smooth characteristics, as pictured here with raised features and deep valve pockets. Compression height can also be increased, which increases the distance between the center of the pin bore and the crown of the piston.
    A high-level overview of which applications can benefit from increased compression ratio can be helpful when assessing whether a high-compression upgrade is a good choice for your machine. Since increasing the compression ratio increases power and heat output, applications that benefit from the additional power and can cope with additional heat realize the most significant performance gains. Contrarily, applications where the bike is ridden at low speed, in tight conditions, or with lots of clutch use can be negatively impacted by incorporating a high compression piston. Keep in mind these statements are generalizations, and every engine responds differently to increased compression ratios. Below are lists of applications that may benefit from increasing the compression ratio as well as applications where increased compression may negatively influence performance. 
    Applications that may benefit from utilizing a high compression piston:
     Motocross  Supermoto  Drag racing  Road racing  Ice racing  Flat track  Desert racing
    Motocross and less technical off-road racing are two of multiple forms of racing in which high-compression pistons can benefit performance due to higher speeds and better air flow to keep the engine cool. Peick photo by Brown Dog Wilson.
    Applications that may be negatively affected by utilizing a high compression piston:
     Technical off-road/woods riding  Trials  Other low speed/cooling applications
    Lower speed racing and riding may not benefit as much from a high-compression piston, as heat in the engine will build up quicker due to lessened cooling ability.
    Fortunately, if you’re considering increasing your engine’s compression ratio by utilizing a high compression piston, many aftermarket designs have been tested and optimized for specific engines and fuel octane ratings. For example, JE Pistons offers pistons at incrementally increased compression ratios so that you can incorporate a setup that works best for you.
    For example, high-compression pistons from JE for off-road bikes and ATVs are commonly available in 0.5 compression ratio increases. Assume an engines stock compression ratio is 13.0:1, there will most likely be options of 13.5:1 and 14.0:1, so that you can make an informed decision on how much compression will benefit you based on your machine and type of riding.

    From left to right are 13.0:1, 13.5:1, and 14.0:1 compression ratio pistons, all for a YZ250F. Notice the differences in piston dome volume and design.
    If performance is sufficient at an engine’s stock compression ratio, there are still improvements in efficiency and durability that can be made with a forged piston. Forged pistons have a better aligned alloy grain flow than cast pistons, creating a stronger part more resistant to the stresses of engine operation. In addition to forged material, improvements can be made on piston skirt style design to increase strength over stock designs, such as with JE’s FSR designs. JE also commonly addresses dome design on stock compression pistons, employing smoothness across valve reliefs edges and other crown features to improve flame travel, decrease hot spots, and ultimately increase the engine’s efficiency.
     
    Even if stock compression is better for your application; forged construction, stronger skirt designs, and more efficient crown designs can still provide improved performance and durability.
    If it’s time for a new piston but you’re still not sure what compression ratio to go with, give the folks at JE a call for professional advice on your specific application.
    Kevin from Wiseco
    Wiseco's new Garage Buddy engine rebuild kits offer everything you need for a bottom and top end rebuild. From the crank to the piston kit, and even an hour meter to track maintenance, everything is included in one box. Here we take a look at the components included, and the technology behind them.

    So, the time has come for an engine rebuild. Hopefully it’s being done as a practice of proper maintenance, but for many it will be because of an engine failure. Whether the bottom end, top end, or both went out, the first step is to disassemble and inspect. After determining any damage done to engine cases or the cylinder, and arranging for those to be repaired/replaced, you’re faced with choosing what internal engine components to buy, where to get them, and how much the costs are going to add up.
    A full engine rebuild is a serious job and requires a lot of parts to be replaced, especially in four-strokes. You have to think of bottom end bearings and seals, a crankshaft assembly, piston, rings, clips, wristpin, and the plethora of gaskets required for reassembly. If you’re doing this rebuild yourself, or having your local shop do the labor, chances are you don’t have a factory team budget to spend on parts. However, you know you want high-quality and durable parts, because you don’t want to find yourself doing this again anytime soon.

    Rebuilding a dirt bike engine is an involved job, requiring many parts to be replaced. Missing one seal or gasket can put the whole rebuild on hold.
    You could source all the different parts you need from different vendors to find the best combination of quality and affordability. But, it can get frustrating when 6 different packages are coming from 6 different vendors at different times, and each one relies on the next for you to complete your rebuild.
    Wiseco is one of the manufacturers that has been offering top end kits (including piston, rings, clips, gaskets, and seals) all in one box, under one part number for many years. Complete bottom end rebuild kits are also available from Wiseco, with all necessary parts under one part number. So, it seemed like a no brainer to combine the top and bottom end kits, and throw in a couple extra goodies to make your complete engine rebuild in your garage as hassle free as possible.
     
    Top-end piston kits and bottom-end kits come together to create Wiseco Garage Buddy rebuild kits.
    Wiseco Garage Buddy kits are exactly as the name implies, the buddy you want to have in your garage that has everything ready to go for your engine rebuild. Garage Buddy engine rebuild kits come with all parts needed to rebuild the bottom and top end, plus an hour meter—with a Garage Buddy specific decal—to track critical maintenance intervals and identify your rebuild as a Garage Buddy rebuild. The kits include:
    Crankshaft assembly OEM quality main bearings All engine gaskets, seals, and O-rings Wiseco standard series forged piston kit (piston, ring(s), pin, clips) Small end bearing (for two-strokes) Cam chain (for four-strokes) Hour meter with mounting bracket and hour meter decal   
    Open up a Garage Buddy kit, and you'll find all the components you need to rebuild your bottom and top end.
    2-stroke and 4-stroke
    Whether your machine of choice is a 2-stroke or a 4-stroke, Wiseco can help you with your rebuild. 2-stroke Wiseco Garage Buddy kits include everything listed above, featuring a Wiseco forged Pro-Lite piston kit. You don’t even have to worry about sourcing a small-end bearing, that’s included too. 2-stroke fans often brag about the ability to rebuild their bikes so much cheaper than their 4-stroke counterparts, and they’ll have even more ammo for bragging now with these kits starting in the $400 range.

    A Wiseco 2-stroke Garage Buddy kit includes all the parts you'll need for piston and crankshaft replacement, plus an hour meter to track your next maintenance intervals.
    However, don’t abandon your 4-stroke yet. Many riders cringe—and rightfully so—at the thought of rebuilding their 4-stroke because of the costs associated, but Wiseco 4-stroke Garage Buddy kits starting in the $600s takes a lot of sting off your rebuild project. They even include a new timing chain.
    No matter what you’re rebuilding, you’ll be able to track key maintenance intervals for your fresh engine with the Wiseco hour meter and log book that’s included in the Garage Buddy kits. All Garage Buddy kits include a specific hour meter decal as well, which is important for the limited warranty to identify the rebuild as a Garage Buddy rebuild.

    A Wiseco 4-stroke Garage Buddy kit includes all the parts you'll need for piston and crankshaft replacement, including a cam chain and an hour meter.
    Ease of ordering
    Wiseco Garage Buddy kits come with the listed parts boxed up in one box, and listed under one part number, which makes it nice to not have to worry about if you might’ve missed something when ordering. Simply find the single part number for your model, order, and you’re on your way to brand new performance.

    Quality Performance, backed by a Limited Warranty
    Ordering convenience doesn’t make a difference if the parts do not provide quality and reliability. Wiseco crankshafts are designed completely by in-house engineers, who determine all assembled dimensions, clearances, materials, and specifications. These specifications have been determined from R&D tests such as hand inspection, dyno, and failure analysis.
    Once Wiseco cranks have been manufactured to exact specifications they are batch inspected, and critical tolerances and dimensions are measured. Major inspections and tests include crank run-out and trueness, because they must operate within a strict tolerance to last long and perform well.

    Wiseco crankshafts and bearings are manufactured and tested according to strict tolerances and clearances, including run-out and trueness. Crankshaft designs are also tested for 4 hours at WOT.
    Bearings are another critical point of inspection. Wiseco has worked to build relationships with top-tier bearing suppliers to provide a long lasting, low-friction product. Debris in a bearing can lead to very fast wear, and Wiseco makes it a point to inspect batches of bearings for cleanliness and proper operation.
    As part of the design and engineering process, prototype crankshafts are hand inspected and dyno-tested at wide open throttle for 4 consecutive hours. This is a benchmark test, and new crankshaft designs must pass it before to be deemed worthy for manufacturing.

    Watch our crank R&D and inspection process.
    A Warranty on Engine Internals?
    Yes! Wiseco is committed to providing performance and reliability in all their products. This is why Garage Buddy kits come with a limited warranty. Rebuild your engine with a Garage Buddy kit, and your new Wiseco components are covered against manufacturer defects for 90 days from the date of purchase, or 10 hours logged on the hour meter, whichever comes first. Check out all the warranty details on the detail sheet in your new Garage Buddy kit.

    Open up your Garage Buddy kit and you'll find a detail sheet on the warranty on your new components.
    Forged Pistons
    The top end kits included in Garage Buddy kits feature a Wiseco forged piston, which are designed, forged, and machined completely in-house in the U.S.A. Four-stroke Garage Buddy kits come with a Wiseco standard forged piston, which offers stock compression and more reliability and longevity, thanks to the benefits of the forging process.
    Two-stroke Garage Buddy kits include a Wiseco Pro-Lite forged piston, which is the two-stroke piston that has been providing two-stroke riders quality and reliability for decades. Some applications, two and four-stroke, even feature ArmorGlide skirt coating, reducing friction and wear for the life of the piston.
    Forged aluminum has an undeniable advantage in strength over cast pistons, thanks to the high tensile strength qualities of aluminum with aligned grain flow.
    Read more about our forging process here, and get all the details on our coatings here.
     
    All Wiseco pistons are forged in-house from aluminum. Some pistons may also come with ArmorGlide skirt coating, and some 2-stroke pistons may already have exhaust bridge lubrication holes pre-drilled.
    All pistons are machined on state-of-the-art CNC machine equipment, then hand finished and inspected for quality. The forged pistons come complete with wrist pin, clips, and high-performance ring(s).
    Lastly, all gaskets and seals are made by OEM quality manufactures. Sealing components are not something to ever go cheap on, because no matter how high-quality your moving components are, if your engine is not sealing properly, it’s coming back apart.
    Need some tips on breaking in your fresh engine? Check this out.
     
    Gaskets and seals provided in Wiseco Garage Buddy kits are OEM quality, ensuring your freshly rebuilt engine is properly sealed.
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