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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.

    Kevin from Wiseco
    Profile and ovality are two main characteristics of piston design. Here we'll take a look at why pistons are designed to not be perfectly round.
    When you look at a piston, it is easy to think that they are a perfectly round,  cylindrical shape. After all, they go into a round hole (the cylinder!) So why shouldn’t they also be round?
    The fact is, the external shape of a piston is very sophisticated. An internal combustion engine is a hostile environment where combustion gasses can reach dangerous temperatures, and there could be port windows and surface undulations from uneven cylinder cooling. Designing a piston that is optimized for combustion chamber conditions is an important challenge.
    Throughout the years, piston materials and design characteristics to compensate for expansion under heat have evolved. Forging pistons out of aluminum provides great strength and durability, but it must be used in the correct design to properly optimize the performance of the piston.
     
    (Left) These are an example of early piston design, using steel as the primary material. These would not be sufficient for the requirements of modern engines. Compare with the variety of modern forged aluminum pistons from Wiseco (right) featuring different coatings and designs.
    Read more about the forging process here.
    There are two major characteristics of piston shapes: profile and ovality. Wiseco's Product Manager and long time engineer Dave Sulecki commented on these piston characteristics: “Piston profile and ovality are one of the most important features of a piston, these really determine not only how the piston will wear over time, but also how well the piston can perform. When the engineer calculates the piston to cylinder clearance, this is only the beginning of a complex determination of the final piston geometry."
    Profile
    If you roll a piston across a flat surface, you'll notice it does not roll in a straight line. You are observing characteristic number one: profile. Because aluminum conducts so much heat, pistons are designed with a taper -- the top of the piston, near the crown, is a smaller diameter than the bottom of the piston, near the skirt. The skirt of the piston actually is designed with what is called a barrel shape, illustrated below. This is beacuase temperatures near the dome of the piston vary from the temperatures at the skirt of the piston, resulting in different levels of expansion. The tapered shape allows the piston to expand as heat is applied, so the piston does not bind in the cylinder bore. The higher the temperature, the more the piston will expand. The design challenge then becomes calculating the degree of taper. Too tight of clearance can induce scuffing or seizure from heat expansion, while too loose of clearance can introduce noise from piston rock.

    This illustration shows piston profile: the barrel shape and taper pistons have. Because of this, measuring diameter on the skirts yields a larger number than measruing near the dome.
    "The piston profile is critical to how the piston will support itself as it reciprocates in the cylinder bore. For example, the piston profile must help hold the piston vertical in the bore during combustion; imagine any excess leaning of the piston would allow piston rings to become “unseated” and not seal properly against the cylinder wall," elaborates Sulecki.
    Ovality
    As you roll the piston across the table, you will also observe the piston rising and falling in a “hump-hump-hump” motion, much like a wheel that has a flat spot. This characteristic is called ovality, also known as camming. In the simplest terms, ovality means that the piston is smallest in line with the wrist pin bore.
    As the engine begins its movement, the connecting rod is not moving only up and down, but due to the rotation aspect is simultaneously moving sideways. This action from the connecting rod and the motion of the crankshaft place load forces on the piston along the plane of the connecting rod inline with rotation (known as the “thrust axis”). To allow the piston to move freely with this sidelong force, the piston cannot be perfectly round, or it would bind in the round cylinder bore. By applying ovality to the piston, the piston is free to move up and down as needed. The challenge in design is applying the proper amount of ovality. Too little ovality can cause the piston to contact the cylinder wall nearest the end of the piston pin, while too much ovality can cause the piston to ride too heavily against the cylinder wall along this “thrust axis.” Too much load along the thrust axis can result in heavy scuffing or seizure, when the piston breaks the oil film barrier and contacts the cylinder wall directly.

    This illustration shows piston ovality. The solid-lined ellipse represents the diameter of the piston as if you're looking down onto the dome.
    Dave Sulecki commented on ovality, "Ovality is an unknown thing, when most people look at a piston they think it is round, and to the naked eye this must be the case. However, take a new two stroke piston and roll it across the table and what happens? You will see the uneven “hump, hump, hump” as the piston rolls in a large arc…you are seeing both the profile (the “cone shape” of the piston”, in combination with the ovality as the piston rolls unevenly. Ovality is necessary for the piston to move up and down in the cylinder bore, as the crankshaft and connecting rod try to force the piston upward, and combustion forces the piston downward, ovality allows the piston to move without binding in the round cylinder bore."
    Your bike's engine need a complete rebuild? Or maybe just a piston and valves? Check out our Garage Buddy line of rebuild kits.

    Another visual representation of piston profile and ovality.
    Ovality is a key detail to remember when measuring piston size. The piston must be measured at the bottom of the skirt, 90 degrees from the wrist pin hole to reach an accurate measurement. 
    When measuring piston diameter, be sure you’re using the proper tools. Do not use calipers to measure your piston(s), as you won’t get an accurate measurement. The most accurate tool to use is a set of outside diameter micrometers.
     
    Your piston should be measured at the bottom of the skirt, 90 degrees from the pin hole.
    Please note: The measurements displayed here are for representational purposes only. Measure each of your own individual parts for accuracy.
    Some Wiseco pistons feature proprietary skirt coatings such as ArmorGlide or ArmorFit, which are designed to reduce wear, provide smoother and quieter operation, and are applied to last for the life of the piston. With certain skirt coated pistons, piston-to-wall clearance measuring specs will change, so be sure to read the instructions that come with your piston(s).
    Click here to find out more about Wiseco's different coatings.
    Freemotion
    We brought the Leatt 6.5 Velocity along with us on our first trip to Moab. It was a great trip and we got in some great riding. We thought wearing the goggles all day in the heat & sun would give us a good feel for their performance. Just wanted to share some pictures from the trip and and what we liked & didn't like. 

    2018 KTM 300 XC-W Six Days ThumperTalk 20th Build we Rode in Moab

    Leatt 6.5 Goggle in Moab
    One of our favorite things: Safety. Like everything Leatt makes safety is a chief concern. They carried that over in the goggles and have the highest impact rating out of any goggle. They are actually bulletproof. Well, from a .22lr bullet, but it's still a bullet! They carry the Military Ballistic Impact Rating certification, actually. At least you know your eyes are safe from roost.

    Me hoping to see some carnage from the side by sides, no rollovers
    We were out in the sun riding for about 4 days straight. When you order the goggles you can choose how much light transmission you want to allow. AKA- how much tint on the lens do you want. You can transmit anywhere between 22-83% light transmission(VLT). The ones I wore all week were 28% light transmission. So, a decent amount of tint. I thought it was the perfect amount. I like little tint in my goggles anyway.   

    Choose how much lens tint you want when ordering. These are 28% VLT

     
    If you've ever been to Moab you know it's mostly rock, at least the fun stuff for bikes to ride is. The goggles didn't seem to move on my face when bouncing along over the rocks. That was nice. Sometimes the face of the goggle will slip and slide with your helmet and that can be frustrating depending on when it happens. Im not sure if its the wide 50mm strap or the silicone coating doing the work but its nice not to have any movement. 

    50mm strap with anti-slip coating

    Triple layer foam was comfortable, even soaked in sweat
    I never felt like my field of view was restricted at all. I think the 170* field of vision is achieved by how rounded the goggles are coupled with how they cut the foam. The foam is cut out along your peripheral vision and opens your field of vision up. Thought that was a nice little differentiator from other goggles. 
    We didn't need a roller system but for one section. There was a section that was non-stop riverbed crossings and me and the crew were all riding through throwing water and mud everywhere. We did manage to take come pictures of the system before we get everything filthy though!

    Roller system is additional $20

    Pick your flavor 
    One of the things we did not like was they are a bit heavier than some of the other goggles we have tested, like the Scott Prospect for example. Now, some people don't care about weight and it's never a concern and additional weight usually translates into additional structural strength. But we just know how they hold up long term just yet. 
    All in all it was a good trip and we got some god use out of the goggles. Especially for the first generation of this goggle Leatt did a great job of understanding what consumer wants, like being able to wear glasses with the goggles, and strives to deliver that at a good price point. 
    They are $79 retail & $99 with a roller system so not bad at all considering you can spend 2x that on other premium goggles. 
    No real drama on the trip other than having a tire bead fail about 10 miles in on the first ride out! I put in mousses for Moab and the tire ended up failing on a mild rock face and would not hold the bead. 

    Impromptu bike stand 

    Had to put zip ties around tire so it would stay on the rim and then limped the bike back

    Not the best place for this to happen
    It was a great trip and we're already planning the next one! 

    You can check these out on Leatt's website here. (We do not get anything if you order)
    Rob@ProX
    Many riders associate the need for a bottom end rebuild with a costly trip to the shop. However, saving on labor and parts isn't out of the question with the help of ProX. We put together a list of 10 tips to help those who want to tackle the rebuild themselves.
    Rebuilding the bottom end of your engine, whether two or four-stroke, can be a fun and rewarding job. Additionally, a considerable amount of money can be saved by taking on the work yourself versus tasking a shop to perform the work. These statements are only true, however, assuming the bottom end rebuild is performed correctly. This is a huge caveat, and for the average weekend warrior who doesn’t perform this task often, unfamiliarity with technique and componentry can lead to errors.
    To help ensure your next bottom end rebuild is executed to a professional level, here’s 10  tips which will elevate your confidence and understanding as an amateur engine builder. The tips will be presented in chronological order. Let’s get started!

    Rebuilding the bottom end yourself can be a daunting, yet rewarding, task. Just make sure you take the engine out of the frame first!
    Correct Tools, Correct Diagnostics, Correct Expectations, Correct Replacement Components
    Successfully rebuilding your bottom end starts with planning and preparation. Starting with tools, you’ll need a few specialty tools in conjunction with your standard sockets, wrenches, etc. Namely, the correct flywheel puller for your specific engine, a flywheel holding tool, a crankcase splitting tool, a blind bearing puller, and a crankshaft puller. Using heat to assist in removal/installation of the bearings and crankshaft is an effective method, so an oven and freezer are also noteworthy items.
    You need to have a copy of the factory service manual or equivalent for your particular vehicle. I highly recommend reviewing the sequence of events and procedure in advance of executing the work.

    If you are rebuilding the bottom end because of a failure, be sure to inspect all components to identify the cause of the failure and determine what was damaged. This will ensure your rebuilt engine will not encounter the same problem.
    Bottom ends are taken apart for many different reasons. If a major failure occurred, the scrutiny of the rebuild will be at a much higher level than a bottom end that is merely being reconditioned. If any problems were persistent when the machine was operated, such as a poorly shifting gearbox, or leaks between the crankcases, the causation of these issues must be identified prior to reassembly.
    Replacement components are a major factor to consider, both in terms of cost and engine performance, when diving into a bottom end rebuild. Replacing bearings, seals, gaskets, and refurbishing the crankshaft either by rebuilding or replacing it is essential. It’s recommended to peruse your service manual or microfiches ahead of the rebuild to generate a list of replacement components.
    Selection of components and sourcing them should also be planned out. In addition to OEM options, brands such as ProX offer OEM quality parts at more affordable prices. Complete crankshafts, connecting rod kits, bearings, seals, and many other components can be found for a wide variety of engine models that can make the rebuilding process easy and affordable. All ProX bottom end parts are made by OE manufacturers and suppliers to OE standards, so your mind can rest easy that your rebuild can retain OEM quality and longevity.
    Click here to see more about ProX drop-in ready complete crankshafts.
     
    ProX bottom end components are manufactured by OE suppliers to OE specifications. Crankshafts, gaskets, seals, and bearings are available to cover your bottom end rebuild with OEM reliability and performance.
    Find all the OEM replacement parts you need for your bike here.
    Keeping Track of Hardware
    As the engine is torn apart, you will amass a significant number of components, bolts, nuts, and miscellaneous hardware. Properly keeping track of these items is critical. I prefer to lay sub-systems out on a large table, remove the bare minimum of components/hardware to get to the items I’m servicing, and stick bolts through cardboard in the pattern they were removed from components (think crankcases and covers). This methodology reduces the number of mixups that can occur and ensures bolts of varying length will be reinstalled in their original location. While my method is far from the only one, make sure you have a robust and sustainable system for keeping track of everything. 
    Flywheel Removal
    Commonly, two specialty tools are required to remove the flywheel - a flywheel puller and a flywheel holder. It is imperative that both are utilized. Many rebuilds have gone awry because a flywheel holding tool was not used during the rebuild. Instead, the crankshaft was secured from the primary drive side when the flywheel nut was removed/installed. At face value, this may not seem like a big deal, however, when the flywheel is removed, or more importantly installed, in this fashion, a torque is exerted across the crankshaft. While it may seem implausible, the twisting force that is exerted can actually alter the trueness of the crankshaft.

    Using proper tools is critical. Pictured here is a clutch holder, used in aiding in clutch component removal, which also doubles as a flywheel holder. The small dowels on the back of the arms of the tool sit inside the recesses in the flywheel to hold it in place while removing the flywheel.
    Crankcase Separation
    There are a few noteworthy items to discuss when separating the crankcases. First off, I always recommend blocking the crankcases so that the split line lies horizontally, and confirming which side should be oriented face up. Doing this will reduce the likelihood of components falling out and ensure that subsequent removal of components goes smoothly.
    When installing the crankcase splitter, make sure a protective cap is used to cover the end of the crankshaft. This applies to both two and four-strokes, but is especially critical on four-stroke engines that pass oil out the end of the crankshaft.
    Be sure to position the crankcase splitter arms as close to equispaced from one another as possible. Also, ensure that the splitter studs utilize thread engagement at least 1.5 times the diameter of the bolt. For example, most crankcase bolt holes are 6mm, so the stud should be screwed down at least 9mm to ensure adequate thread engagement.

    Removing the crank after the cases have been split is another critical job that requiring a special tool. We always recommend using a crank puller. The puller can also be used to install the crankshaft.
    Once the crankcase splitter is set up, it is imperative that separation happens evenly around the periphery of the crankcases. Screwdrivers and the like should never be used to facilitate separation. Instead, a rubber mallet can be used to encourage separation.
    Seal and Bearing Removal
    The use of seal pullers to facilitate seal removal is not completely necessary, but is definitely recommended. Their use reduces the likelihood of bore damage during removal.
    Bearing removal can be done with or without heat. However, the former seems to be a better method. Using heat to remove the crankcase bearings reduces bearing bore wear and work on part of the rebuilder. I do want to note that your heat source and surrounding area can become odorous due to the residual oils that become heated during the process. For this reason, it is advisable to thoroughly clean the crankcases prior to heating them up, as well as keeping ventilation in mind.

    After heating the crankcase halves, use a hammer and punch to remove any bearings that did not come out on their own. Be careful not to damage the bearing bores when doing this.
    To remove the bearings by heating the crankcase halves, position the crankcase halves split line down on a pair of trays. The trays will catch the bearings and any oil that did not get cleaned out. The oven, grill, or heat source should be set at 350 degrees Farenheit, and the crankcases should be heated for around half an hour. After, the majority of the crankcase bearings should fall out of their bores. Any bearings that did not drop out should be carefully tapped out with a punch and hammer. Bearings situated in blind bearing bores that did not fall out should be removed with the assistance of a blind bearing puller.
    If you do not want to or can’t use the heating method to remove the bearings, an arbor or hydraulic press may be utilized to aid in removal. A blind bearing puller will also have to be heavily relied on to facilitate removal. Due to the unevenness of load distribution that can result from pounding the bearings out with a hammer, we caution against this as a primary form of removal without the aid of heat.
    Cleaning, Case, and Component Inspection
    At this point, it is my recommendation that all components that originated inside the crankcases be thoroughly cleaned. Clean components will ensure easy and accurate inspections. On four-stroke engines that have oil passages running through the crankcases, cylinder, and cylinder head, it is imperative that these are cleaned and blown out. This is especially true if the engine suffered a major failure where oil contamination was a resulting issue. Similarly, on two-strokes, the passages that lead to the crank bearings should be cleaned.
    Component inspections should be conducted to assess the condition of the gearbox, crankcase bearing bores, and crankshaft. The crankshaft should either be rebuilt or replaced depending on the severity of wear and desires of the builder.
    Should you determine you'd like to rebuild your crank, ProX offers OEM quality connecting rod kits that can be used for a crankshaft rebuild. Unless you are experienced in this field and have the tools, crankshaft rebuilds should be trusted in the hands of a reputable shop.

    ProX connecting rods are double-forged, Japanese steel, and are heat treated and shot peened for strength and longevity.
    Read about the advtantages of ProX connecting rods here.
    Crankshaft Trueness
    Regardless of whether a new or rebuilt crankshaft is utilized, the trueness of the crankshaft must be checked. This can be farmed out to a competent shop, machinist, or if properly equipped, performed in-house. While it should normally be expected that new or rebuilt cranks are within runout specifications, the trueness of the crankshaft is imperative to long-term durability. Checking is insurance that our postal system didn’t drop your crank, and that the factory or rebuilder did their job correctly.
    Bearing Installation
    Similar to removal, heat can also aid in bearing installation. The same heating recommendations apply, and once at temperature, the majority of the bearings should fall to the bottom of their bores without any input. The caveat to this is the bearing dropping into the bore cock-eyed. When this happens, a punch and hammer should be used be help square the bearing to its bore. Be sure to tap on the outer race of the bearing. To ensure the bearings are at the bottom of their bores, they should be tapped to confirm they are fully seated.

    Bearings should be tapped on their outer races only to make sure they are completely and squarley seated in their bores.
    Alternatively, if you don’t want to, or can’t use heat, an arbor or hydraulic press should be utilized to install the bearings. Be sure to load the bearings through their outer races when pressing them in place.
    Seal Installation
    Seals can be tapped into place with a seal driver or socket and hammer. Alternatively, a press can be used. The important checks to perform are to ensure the seals have been installed squarely in their respective bores, and at any prescribed depths outlined in the service manual. Any seals installed cock-eyed will wear out prematurely.

    When installing new seals, make sure they are completely seated by using a seal driver or socket and hammer. Use caution and make sure the tools don't come in contact with anything but the seal.
    To prepare for the new bearing and seal installation, complete crankshaft bearing and seal kits are available through ProX. ProX uses reputable, OEM bearing and seal suppliers for all parts in order to maintain OEM quality. Ordering in kits creates less hassle and is a budget-friendly step in your rebuild.
    Click here to check out ProX bearings and seals.
    Crankshaft Installation
    Crankshafts that utilize an interference fit with their mating crank bearings can be installed two ways. Shrinking the crankshaft in place using a combination of heating and cooling of components works well. Alternatively, utilizing a crankshaft puller is another great way to install the crankshaft. Pounding or pressing the crankshaft into place should never be considered because the trueness of the crankshaft can be affected.

    While your crankshaft cools in the freezer, carefully heat the inner race of the crank bearing, paying careful attention not to damage any new seals.
    To shrink the crankshaft in place the crankshaft should be set in a freezer for about an hour, and the inner race of the crank bearing should be carefully heated with a torch. The cautionary point here is to use care when heating if the crank seals have already been installed. Inner race temperature can be gauged by applying a drop of water to the surface of the race. If the water droplet sizzles, the inner race is plenty hot. At this point, the cooled crankshaft can be dropped through the heated bearing. Once seated, work to button up the crankcase assembly should progress quickly, and the remaining inner race can be heated and the crankcase installed.
    Using a crankshaft puller is an equally acceptable method and is incredibly straightforward. The puller is threaded and seats against the crank bearing or crankcase and attaches to the end of the crank via a nut or retaining ring. Once set up, the puller is tightened and the crankshaft is pulled through the bearing. 

    Your cooled crankshaft should fit through your heated bearing fairly easily. A crank puller can be used for installation to make sure everything is square. Also, be sure to use assembly lube in critical areas during assembly.
    At this point, your crankcases should be buttoned up and you should be well on your way to rebuilding the rest of your engine. Upon installation of your flywheel, be sure to use a flywheel holding tool to secure it in place when torqueing the nut.
    Images provided and owned by Kelsey Jorissen Photography, LLC.

    Rob@ProX
    Periodically inspecting and replacing the chain on your motorcycle or ATV is part of regular maintenance. Here, we go over steps and key tips for replacing your worn out chain with a new one.
    The necessity to periodically replace the chain on off-road machines comes as a byproduct of operating in harsh environments containing dirt, mud, sand, etc. On road machines aren’t exempt from this maintenance task either, however, their replacement intervals are longer. Replacing your machine’s chain isn’t a tough job if you’re well equipped and prepared to take on the task.

    Replacing your machine's chain is part of normal maintenance and should not be neglected.
    To start, it is essential to have a copy of your machine’s factory service manual. Within the service manual, you’ll find specific instructions and torque specifications that may be required to complete the job. For example, if either of the sprockets requires replacement, it is imperative the nuts and bolts that secure them are torqued to the outlined specifications.
    Before purchasing a new chain, you’ll want to confirm that the sprockets are in good condition. Pairing a new chain to worn sprockets will accelerate the rate of chain wear and be counterproductive. You’ll also want to inspect components that come in contact with the chain such as chain slides and rollers. Replacing these components at the same time as the chain is advantageous.
     
    Inspect your sprockets before beginning the new chain install process. Notice how the grooves in the worn sprocket are asymmetrical in comparison to the new sprocket.
    Inspections
    Sprocket condition can be checked visually by looking at the sprocket teeth. Sprocket teeth take on a hook shape when they become worn, and in severe cases, shorten and round off when service has been severely neglected.
    If funds allow, it’s always best practice to replace both sprockets when replacing your chain. This will allow for the most life possible out of your drive system.

    Don't let a worn sprocket ruin your new chain. Replace them when you replace your chain.
    The condition of the chain can be assessed by putting the bike on a center stand. Rotate the rear wheel and visually inspect the chain’s condition. As you rotate, feel the chain for tight spots or links that are stuck together. Attempt to pull the chain away from the rearmost part of the rear sprocket. If the chain can be pulled off the rear sprocket by a half sprocket tooth or more, it is time for a replacement. Similarly, if the chain moves significantly side to side when pushed and pulled on the sprocket, wear has occurred.

    Check your chain's wear level by attempting to pull it away from the back of the rear sprocket. If it's half a tooth or more, it's time for a replacement.
    Check any chain slides to ensure they have ample life left. Rotate chain rollers to ensure they spin freely.
     
    Check your chain rollers and sliders as well. These are normal wear items, and they should be replaced when they show signs of excessive wear.
    ProX also offer OEM replacement chain rollers in addition to chains and sprockets.
    Chain Sizing and Options
    Off and on-road chains used for powersports applications come in various sizes based on chain pitch and length. Before purchasing a new chain, you’ll need to confirm the appropriate pitch and size for your machine.
    Chain pitch defines the distance between the chain pins. Common pitch options are shown in the table below along with their corresponding dimensions.

    There are a couple of ways to determine the type of chain your machine utilizes. First, your factory service manual should contain this information. This is usually found in the rear wheel specification table. Second, most chain manufacturers denote the chain’s pitch on the side of the chain. You can obtain the chain’s length simply by counting the number of chain links it has.

    Many chain manufacturers will indicate the pitch on the links of the chain itself.
    Once you’ve determined the chain pitch and length you need, you’re ready to order. When it comes to ordering, you’ll need to decide on the type of master link connection you want and whether the chain is a standard chain or a sealed chain.
    The most common chains in dirt bike and ATV applications are 420 (for minis) and 520. ProX offers both sizes of chains. ProX 520MX chains are available in both standard and X-ring, in standard and gold finishes. The gold finish is the result of a rust-resistant coating. ProX chains are made in Japan from high-quality Japanese steel. These chains come with master link style connections, which is the most common in modern off-road applications.

    520 is the most common size for modern off-road motorcycles, and 420 is a common size for minis.
    Master Link Connection
    Clip Type - Clip type connections are widespread nowadays and are notable for their ease of installation. Clip type master links are not quite as strong as rivet type. However, they can be installed with no special tools.
    Rivet Type - Rivet type master links require a special rivet tool to install but offer a more permanent connection.

    A clip type master link.
    Chain Seals
    The difference between a standard chain and a sealed chain is that the former does not use any type of seal to retain chain lubricant. Sealed chains, often referred to as O-ring chains, utilize O-rings or similar variants to retain lubricant which helps reduce wear and prolong chain life.
    There are different styles of O-ring chains available, such as ProX’s X-ring chains. ProX’s X-ring chains are a sealed O-ring chain but have less O-ring surface area touching the link surfaces to reduce the drag in comparison to a normal O-ring chain. The advantage is in the design of the O-rings themselves.

    CLICK HERE for a full explanation of the differences between standard and O-ring chains to help you decide which one type is right for you.
    Tools
    To replace a chain that utilizes a clip type master link, you’ll need the following:
    Pliers for pressing on the chain plate or master link plate pressing tool. Pliers will also be used to install the master link clip. Flat blade screwdriver for removing the master link clip. Grinder, punch, and hammer, or chain breaker tool to adjust chain length. To replace a chain that utilizes a rivet type master link, you’ll need the following:
    Chain rivet tool for installing the master link. Grinder, punch, and hammer, or chain breaker tool to adjust chain length and to remove the old chain.
    Ensure you have the proper tools before beginning your chain replacement job.
    Chain Removal
    On chains utilizing a clip type master link, chain removal is as simple as prying off the master link clip and removing the master link. Through use, the master link plate usually wears enough so that it can easily be slid off the link. If the master link plate is tight, the master link should be driven out by using a punch and hammer or chain break tool.
     
    For clip style chains, one easy way to remove the master link clip is to use a pair of pliers to push the clip off by using the chain pin for leverage.
    Chains utilizing rivet master links will require pin grinding so that one of the links can be removed. Grind the rivets that retain one of the links flat, then use a punch and hammer or chain break tool to push the chain link out.
    Chain Installation
    If necessary, resize the chain to your machine by removing the appropriate number of chain links. Remember to count the chain links of the old chain to establish the length of the new chain. Don’t lay them side by side and try to set the length because the chain stretch that occurred in the old chain will lead to an incorrect chain length of the new chain.

    Chains almost always need to be sized (have links removed). Your manual should specify the required number of links, but sizing it up on the bike will give you a good idea if your rear axle will be in the recommended position.
    Chain links can be removed by carefully grinding the rivet flat to the chain side plate, then driving the pin out with a punch and hammer. Alternatively, a chain break tool can be used.

    Sizing the chain can be done by grinding and punching, but the easiest way to remove links is to use a tool made specifically for the job.
    Loosen the rear axle nut and slacken the chain adjusters. The new chain will necessitate this since it has not worn or stretched.
    Position the two chain ends on the rear sprocket. Next, install the master link whether clip or rivet type. Be sure to include the o-rings when installing sealed chains.
    Clip Type Master Link Install
    Once the master link has been installed, install another pair of o-rings (on sealed chains) followed by the master link plate. The master link plate will need to be pressed onto the master link. Use a pair of pliers to squeeze the plate onto the master link. Press the plate on far enough so that the grooves that retain the master link clip become exposed. A pair of small c-clamps can sometimes be helpful when installing the plate, or a master link plate installation tool can be utilized.
      
    Place your master link through the wheel side of the chain so the clip will face out. Next, press the master link plate on the outside of the link. Using a pair of pliers to press the plate past the grooves on the chain pins should  be sufficient.
    Next, install the master link clip. The master link clip is directional and should be oriented so that the closed end of the clip leads the direction of rotation. By orienting the clip this way, should the clip hit an object during operation, it will not become dislodged from the master link. To install the master link clip, position it in its mating grooves on the master link. Use pliers to seat the clip fully in its grooves.
     
    Now, install the master link clip. The closed end of the clip should lead the direction of forward rotation of the wheel. Use a pair of pliers with leverage against the pin to fully snap the clip in place. Be sure it is fully seated.
    Rivet Type Master Link Install
    To install a rivet type master link, you will need a master link rivet tool. It’s recommend to follow the instructions provided with the tool to perform the rivet operation. The chain manufacturer will also provide specifications which govern the appropriate amount of flare to add when deforming the rivets.
    Setting Chain Slack
    Once the master link has been installed the chain tension should be adjusted so that the machine has the appropriate amount of chain slack. Your machine’s service manual will outline how to measure the chain slack and define the slack range. Most manufacturers recommend measuring chain slack with the bike on a center stand. Slack is then measured by pulling up on the chain near the center of the swingarm and measuring its displacement. Most dirt bikes require 30 - 60mm (1.18 - 2.36 inches) of chain slack. Carefully manipulate the chain adjusters so that they tension the chain evenly and align with the same reference points from side to side. Once chain slack is correctly set, torque the rear axle nut to the specification outlined in your service manual.
     
    Once installed, adjust your chain slack to the recommended spec using the axle block adjusters. Secure the lock nut when finished, then torque the rear axle nut to spec.
    Post Installation Tips
    Most chains are pre-stretched to reduce the amount of initial chain stretch that occurs once the chain is put in use, however, it is never a bad idea to keep an eye on the chain slack after the first few rides.
    New chains come pre-lubricated from the factory. However, you should always ensure your chain stays lubricated throughout its life. Lubing your chain before or after every ride, especially muddy or rainy ones, should become habitual.
    Find ProX chain and other components for your bike HERE!

    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.
     
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