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      JUST IN!   07/17/2018

      Video: 2019 Yamaha YZ250F Features & Benefits 


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    Video: 2019 GasGas Enduro Range
    The highly competitive GasGas EC enduro and XC cross-country models renew their image by incorporating improvements in the frame and suspension, the engine and the electrical system. The brand from Girona updates the looks of its enduro while keeping intact the wild, attractive line of its unmistakable two-stroke off-road models.  
    Posted by Bryan Bosch on Jul 17, 2018

    Antigravity Batteries Lithium Ion Battery with Restart Technology
    I don't know anyone that doesn't love how light weight lithium ion motorcycle batteries are, but there are still plenty of critics of the technology as it relates to reliability, especially for those that ride in very cold conditions. In some cases, lead acid batteries very well might be a rider's best choice, but there is no question that light weight batteries have come a long way, both in terms of performance and reliability.  Lots of cranking power in a lightweight package So Cal based Antigravity Batteries appears to be one of the leaders pushing the envelope in the lightweight battery segment, recently releasing a "smart" battery that addresses one of the killers of lithium ion batteries: over discharge.  Select Antigravity Batteries feature tech called "RE-START". Simply put, if the on-board battery management system (BMS) detects that the battery is in danger of becoming over discharged, it will automatically put itself into a protective state, preserving enough power for a few starts. Push the RE-START button (remote triggering coming soon) on the battery to bring it back to life. Antigravity Batteries RE-START tech really appeals to me, as my KTM 690 Enduro R has no back-up kickstarter, something we're seeing more and more of. Installation of the Antigravity Batteries RE-START battery was a piece of cake with a negative and positive terminal on both sides of the top of battery. It also fit snugly into the factory battery box, but the factory aluminum retention strap appeared to slightly cover one edge of the RE-START button on the top of the battery. Fortunately I could still hear an audible "click" when pushing it, verifying that the button is still functional. Fortunately I can remove my seat to access the RE-START button without tools, but I can see why Antigravity is coming out with a remote for motorcycles where battery access is more challenging. Press the RE-START button to bring the battery back to life Does the RE-START tech work? Absolutely. To test this, I hooked-up a 12v fan directly to the battery and let it run until it stopped. I pressed the RE-START button once, hit the eButton, and my bike turned over and started like it normally does. Nice! Recently a riding buddy swamped his KLR during a water crossing and in the process of getting the bike restarted, after maybe a dozen pushes of the eButton, without notice, his competing brand lithium ion battery became over discharged, and he was stranded. This is a perfect example of what Antigravity Batteries RE-START technology was designed to avoid.  Over the last several months of riding with my Antigravity Batteries RE-START lithium ion battery, it's been flawless. This includes sitting in a hot Florida garage for a couple of weeks when it was raining non-stop without being charged, start/stop/start/stop dual sport duty, and a number of weekends of hot, humid, & wet Florida trail riding. On my last riding trip to the Ocala national forest, it was super hot, humid, and I was really working the bike riding in deep sand. When taking trailside breaks, the radiator fan would run for 4 to 5 minutes each time (key on with headlight on), and when I hit the eButton, the starter turned over the engine with ease, lighting quickly. With 360 cranking amps @ 10Ah vs. the stock lead acid 190 @ 9.1Ah, I'm not surprised. Pros  Huge weight savings over lead acid (2.5lbs. vs. 6.625lbs.). Faster starts because of stronger cranking power. Smart technology that keeps you from being stranded. Smart technology that extends battery life. Flexible 4-terminal design. Cons  Until remote RE-START button is released, for some bikes, getting to battery RE-START button could be challenging. Bottom-line  If you want the weight savings that lithium ion batteries offer, but without the risks of being stranded from being over discharged, Antigravity Batteries RE-START battery is not only a good choice, being the first of its kind, it's your only choice.
    Posted by Bryan Bosch on Jul 17, 2018

    Suzuki Introduces 2019 Motocross, Dual Sport, Off-Road and Youth Models
    All-new RM-Z250 and DR-Z50 top the list of updated and returning models  BREA, CA – July 17, 2018 – (Motor Sports Newswire) –  Led by the advance look at an all-new RM-Z250 motocross machine and the new DR-Z50 mini, Suzuki Motor of America (SMAI) is proud to announce the introduction of its 2019 Motocross, DualSport, Off-road and Youth models including the QuadSport Z90 and QuadSport Z50 ATVs. The completely updated RM-Z250 features a long list of enhancements and performance improvements and now mirrors the cutting-edge styling of its big brother RM-Z450, introduced just last year. For young riders just starting out, Suzuki offers the new DR-Z50 mini. Featuring a host of convenience and safety features, the DR-Z50 is the perfect way to introduce youngsters to the thrill of dirt bike riding. All-new from the ground up in 2018, the RM-Z450 returns with key updates to its suspension while Suzuki’s versatile DualSport and DR-Z400SM models continue to provide owners with class-leading performance whether riding on- or off-road. For those ready to take Suzuki’s renowned motocross bike handling to the trails, the RMX450Z returns for serious desert and woods riders. The DR-Z125L is everyone’s favorite trail bike and returns with RM-Z inspired graphics. 2019 Motocross Models Suzuki’s tradition of building championship winning, high performance motocross machines takes the next step forward with the pre-announcement of the all-new, 2019 RM-Z250. Designed to move it to the head of the 250 class, this all-new stunner features a long list of enhancements and performance improvements. Preliminary information on this new motorcycle is available now with full product details and specifications set to be announced in September. Evolving the fundamental performance elements of ‘RUN’, ‘TURN’ and ‘STOP’ to a new level, Suzuki has infused the Winning Balance into the new 2019 RM-Z250. Suzuki engineers have achieved an even greater level of balance between the race-proven performance of the RM-Z250’s engine and chassis. Particular attention was focused on advancing its ‘TURN’ capabilities to continue Suzuki’s tradition of producing the best handling motorcycles on the racetrack. The styling of the RM-Z250 is all-new and unified with that of the RM-Z450. NEW 2019 RM-Z250 New Aluminum Frame & Swingarm More Power and Improved Throttle Response Sleek New Bodywork & Ergonomics New Coil-spring Fork & Shock/Linkage Champion Yellow with Red/Blue Graphics MSRP $TBA Estimated arrival at dealers: February 2019 *Additional information will be available in September 2018 With a decade’s worth of race win dominance, the 2019 RM-Z450 remains the champion’s choice. Fully-revised in 2018, the RM-Z450 returns with its sleek, race-ready appearance, strong engine and a nimble chassis that continues Suzuki’s tradition of having the best handling 450. To further improve the agile RM-Z450, a new spring has been fitted to the SHOWA BFRC shock with new damping force settings while the coil-spring fork has new damping-force settings as well. Continual improvement is why the RM-Z450 remains the class standard for cornering performance. 2019 RM-Z450 DOHC 4-valve, 449cc, 4-stroke Engine Suzuki EFI with Tuning Coupler System Twin-spar Aluminum Frame & Swingarm New Rear Shock Spring Updated Suspension Settings Champion Yellow with Red/Blue Graphics MSRP $8949 Estimated arrival at dealers: August 2018 2019 RM85 The Choice of Future Champions Strong & Reliable 84.7cc Two-stroke Engine Six-speed Transmission & Manual Clutch Fully Adjustable SHOWA Suspension Champion Yellow with Red/Blue Graphics MSRP $4199 Estimated arrival at dealers: November 2018 Enlist in the RM ARMY and enjoy Suzuki Amateur Racing Support! Suzuki’s renowned RM Army and Amateur Racing Support continues, offering over $3.8 million in contingency, trackside support, and the opportunity to train with Ricky Carmichael at Suzuki’s exclusive Camp Carmichael. Want to see why champions choose Suzuki? Visit www.racesuzuki.com for more information on Suzuki’s Amateur Support Program and enlist in the RM ARMY! 2019 DualSport Models Suzuki offers the best all-around selection of DualSport models in the industry. As evident with the DR-Z400S, Suzuki DualSport models are fun, reliable and capable motorcycles available to anyone who’s ready to take a ride down an off-road trail or ribbon of asphalt. The versatile DR650S sports the ability to reduce its chassis and seat height for rider comfort and confidence while the DR200S is at home trail riding or commuting; delivering an impressive 88 MPG. 2019 DR650S 644cc, Air and Oil-cooled, Four-stroke Engine Push-button Electric Start & Street-legal Lighting Optional Adjustable Seat Height Smooth-shifting 5-speed Transmission Solid Black with Red Graphics MSRP $6599 Estimated arrival at dealers: August 2018 2019 DR-Z400S Liquid-cooled, 398cc DOHC Engine Push-button Electric Start & Street-legal Lighting Slim Chassis with Fully-adjustable Suspension Spoke-style wheels, Aluminum 21” and 18” Rims Solid White Bodywork with Blue/Black Graphics MSRP $6749 Estimated arrival at dealers: November 2018 2019 DR200S 199cc OHC, Four-stroke Engine Low 33.3” Seat Height & 278 Ready-to-Ride Pounds Push-button Electric Start & Street-legal Lighting Over 8-inches of Front and Rear Suspension Travel, Solid White Bodywork with Blue/Black Graphics MSRP $4649 Estimated arrival at dealers: August 2018 2019 Suzuki DR-Z400SM Suzuki’s DR-Z400SM combines a narrow, off-road capable chassis with street-legal components to produce a lightweight, Supermotard package that turns, accelerates, and stops better than many sportbikes. The DR-Z400SM has an inverted front fork, wide, spoke-style wheels sporting sportbike tires, and a 300mm floating front brake rotor. There are two color choices for the 2019 DR-Z400SM; Solid White bodywork with red/black graphics plus gold-anodized EXCEL rims on the wheels, or white bodywork with blue/black graphics and blue-anodized rims. 2019 DR-Z400SM Liquid-cooled, 398cc DOHC Engine Push-button Electric Start & Street-legal Lighting Inverted, Fully-adjustable RM-style Fork Solid White Bodywork with Red/Black Graphics with Wide, Spoke-style Wheels with Gold-anodized Rims 120/70-17 & 140/70-17 Sportbike Tires -Or- Solid White Bodywork with Blue/Black Graphics with Wide, Spoke-style Wheels with Blue-anodized Rims MSRP $7349 Estimated arrival at dealers: September 2018   2019 Off-road Models The new 2019 DR-Z50 is a high-quality, Suzuki-built mini-bike that brings ease and convenience to riders just getting started on two wheels. With an automatic clutch, 3-speed transmission, electric starting and a low 22-inch seat height, this RM-styled bike will help build confidence and riding ability for young, supervised riders. The 49cc engine delivers a smooth, controllable power-band plus adult supervisors can adjust the power level so young riders can learn at a proper pace. Joining the DR-Z50 is the DR-Z125L that’s ideal for riders of intermediate stature and skill, and the RMX450Z that combines elements of the championship-caliber RM-Z450 with features needed for serious trail work. 2019 DR-Z50 NEW Reliable 49cc, 4-stroke Engine Smooth-shifting 3-speed Transmission & Auto-clutch Push-button electric starting with back-up kick starter Keyed Ignition & Power Limiter for Parental Control Inverted Fork & Single Rear-shock Champion Yellow with Red/Blue Graphics MSRP $1749 Estimated arrival at dealers: September 2018 2019 DR-Z125L Compact & Reliable 124cc 4-stroke Single Smooth-shifting Transmission, Easy-pull Manual Clutch Strong Steel Frame & Beam-style Swingarm Telescopic forks & Single, Link-type Rear Suspension Champion Yellow Bodywork with RM-Z Style Graphics MSRP $3299 Estimated arrival at dealers: August 2018   2019 RMX450Z Enduro-ready Off-road Bike based on the RM-Z450 Electric-starting with Kick-start Back-up Competition-ready Instruments and Lighting Black-anodized Wheels with 18-inch Rear Rim Fully-adjustable, SHOWA Fork & Rear Shock Champion Yellow with Red/Blue Graphics MSRP $8999 Estimated arrival at dealers: August 2018   Each new Suzuki DualSport, SuperMoto, Off-road, and ATV model is backed by our Limited Warranty1. Additionally the coverage period and other benefits added through Suzuki Extended Protection. Click here to learn more or visit a Suzuki dealer for details. 1The DR200S, DR650S, DR-Z400S, DR-Z400SM models are covered by Suzuki’s On-road, 12-month Limited Warranty. The DR-Z50, DR-Z125L and RMX450Z models are covered by Suzuki’s Off-road, 6-month Limited Warranty. The QuadSport Z50 and QuadSport Z90 models are covered by Suzuki’s ATV, 12-month Limited Warranty. The competition RM85, RM-Z250 and RM-Z450 models do not have warranty coverage. About Suzuki Suzuki Motor of America, Inc. (SMAI) distributes Motorcycles, ATVs, Scooters, Outboard Motors and Automotive Parts and Accessories via an extensive dealer network throughout 49 states. Suzuki Motor Corporation (SMC), based in Hamamatsu, Japan, is a diversified worldwide manufacturer of Motorcycles, ATVs, Scooters, Automobiles, Outboard Motors and related products. Founded in 1909 and incorporated in 1920, SMC has business relations with 201 countries/regions. For more information, visit www.suzuki.com Suzuki, the “S” logo, and the Suzuki model and product names are Suzuki trademarks or ®. Source: Suzuki Motor of America, Inc.
    Posted by Bryan Bosch on Jul 17, 2018

    5 Key Steps to Training & Racing Well in Heat & Humidity (Pod Cast)
    During this Podcast (#18), I outline How to Train and Race in Hot and Humid Conditions for Optimum Performance.  I walk you through 5 key steps to take prior to, during and following training and/or racing to ensure that you perform well in these difficult situations, along with how to correctly recover in the shortest amount of time.  During the first segment, I also outline how to identify and offset a heat stroke. During segment #2, I  address the Role of Carbohydrates, Protein and Fat as it Relates to Performance.  This includes how each of these plays a significant role in your energy levels, performance levels, and your ability to recover.  You might be surprised to learn what it takes to become both lean and strong! Finally, I answers listener’s questions about eating enough to off-set weight gain associated with stress; how to lose fat and not muscle; why eggs are important in a meal plan; and why do I train faster than I race? If you have any questions that you would like me and/or my staff to research and discuss, please don’t hesitate to drop me an email to: Contact@CoachRobb.com Regards, Coach Robb  
    Posted by Coach Robb on Jul 09, 2018

    How to Rebuild the Top End in your Two-Stroke
    Rebuilding a top end is a task most two-stroke owners will run into at one point or another. Here, we go over critical steps and key tips to installing a new piston and ring(s) in your two-stroke. Periodically, if you own a two-stroke, there will come a point where you need to rebuild the top end of your engine. Hopefully, this won’t come as a surprise to you and will be part of your planned maintenance schedule versus experiencing an unplanned engine failure. While two-stroke engines are relatively simple mechanical devices, rebuilding them requires knowledge of how they work, attention to detail, and a systematic approach. We’re going to cover numerous tips pertinent to two-stroke top end rebuilds. These tips will be discussed chronologically and will encompass all phases of the build from pre-rebuild prep, to disassembly, through post build. The tips we’re going to share shouldn’t be considered inclusive of everything that has to be done, but are tips that focus on things that are either often overlooked or incredibly important. Let’s get started! Pre-Teardown Diagnosis  - Before tearing the engine apart, are there any signs that a specific problem exists? If so, are there any diagnostic tests such as compression or crankcase leak down that are worth performing? Before tearing your engine down, asses the specific problem with you're engine if you're rebuilding due to a running problem. Clean Machine - Take time to thoroughly clean the machine before opening up the engine, especially if you will be servicing the top end without removing the engine from the machine. Service Manual - Performing engine maintenance without an OEM factory service manual is not recommended. Make sure you have a manual for your machine prior to starting work. The manual is the only place you’ll find service limits, torque specs, and other key data. Disassembly Limit Contaminants - Once the cylinder has been removed wrap a clean, lint-free rag around the top of the crankcase. Dirt is one of the leading causes of engine wear, and limiting the opportunity for dirt to enter the crankcase is very important. Keep a lint-free rag at the top of the crankcase at all times while it is open and exposed to potential contaminants. Piston Removal - Easy piston circlip removal can be accomplished by using a pick and needle nose pliers. Insert the pick into the dimple in the piston and behind the circlip. Then use it as a lever and pry the circlip out partially. Once out partially, grab the circlip with needle nose pliers. During this process, be careful not to scratch or mar the wrist pin bore as this will make removing the wrist pin much more difficult. Use tools as needed to aid in circlip removal, but be careful not to mar the pin bore so the wrist pin can be easily removed. The ease of pin removal will be largely dependent on the engine design and condition of the bore. If the pin can be removed by hand, great, if not, light tapping while supporting the rod is permissible. Otherwise, a pin puller should be utilized which can be bought or made. In its simplest form, this can consist of an appropriately sized bolt, nut, and socket. Once the wrist pin has been removed, the piston can be removed from the rod. Hopefully, the wrist pin can be removed by hand once the circlip is out. If not, an appropriately sized socket with some light tapping from the opposite end can help break it loose. Power Valve Disassembly - Prior to taking the power valve system apart, spend some time reviewing the procedure in your service manual. For additional insight into how the components interact, review the exploded views in the service manual and look at part microfiches, which can be found online. Online microfiches can be very helpful to double-check reassembly of the power valve. They can be found on many motorcycle dealer websites. When removing the power valve system, consider laying the components out on a clean rag in an orientation that correlates to how they are installed in the engine. This is a relatively simple thing to do that will help you remember how they are installed later. When it comes to cleaning the components, clean them one at a time or in small batches so that they don’t get mixed up. Lay out all the parts of your power valve assembly as you disassemble it. This will help you keep everything organized, and make sure you get it back together correctly. Inspection Reed Valve - Don’t forget to check the condition of the reed valve petals, cage, and any stopper plates. Most service manuals will detail the acceptable clearance between the petal tips and cage as well as the stopper plate height. Ensure any rubber coatings on the reed cage are in good condition. Inspect all reed valves components thoroughly before reassembling the top end. Any parts showing signs of excessive wear or damage should be replaced. Intake Manifold - Check the intake manifold for cracks. Cracks are more common on older engines, and propagation all the way through the manifold can lead to air leaks. Exhaust Flange - Check the condition of the exhaust flange and ensure that it is not excessively worn. An excessively worn flange will make exhaust gas sealing difficult, hamper performance, and leak the infamous spooge.  Power Valve Components - Take a moment to review the condition of all the power valve components. Significant wear can occur over time and lead to performance losses. Rod Small End - Check the small end rod bore for surface defects such as pitting, scratches, and marring. Any severe defects in the bore will necessitate rod replacement. The rod small end is a critical point of inspection. Any damage to the inside surface could affect the small end bearing, leading to a chain of top end problems and potential failure. Sourcing New Components When freshening up the top end in your two-stroke, it’s important to reassemble with quality components. A deglazed and honed or bored and replated cylinder is a critical component to ensuring reliable performance from your new top end. Your local cylinder shop should be able to handle the bore and replate when necessary, and a simple deglazing can be accomplished with a Scotch-Brite pad. Be sure to retain the 45-degree honing mark angle. There are a lot of choices for new pistons from the aftermarket out there, but many people choose to stick to OEM. However, when ordering from the OEM, every individual part must be ordered separately, including the piston, ring, pin, clips, gaskets, etc. Dealing with all these part numbers and chancing forgetting a component can be a pain, and get expensive. ProX two-stroke pistons are manufactured by OEM suppliers, and come with the piston, pin, ring(s), and circlips all under one part number. ProX two-stroke pistons are manufactured by the same OEM-suppliers to exact OE specs. They are available in A, B, C, and D sizing for most applications. ProX pistons come with the piston, ring(s), pin, and clips all in one box. Complete top-end gasket kits can even be ordered under one part number. ProX pistons provide an OEM-replacement option with less hassle and less strain on your wallet. Find ProX pistons for your bike here. Even though ProX pistons are made by OE suppliers, the quality control difference is evident. On the left is a ProX piston for a Honda CR250, and on the right is a brand new piston out of the box from Honda. Which would you choose? Measurements The number of measurements that should be taken throughout the top end rebuild will be discretionary. At ProX, we strive for excellence and err on the side of caution when it comes to engine building, so our builds consist of numerous measurements and inspections prior to reassembly. For us, this ensures a high level of confidence and safeguards against external oversights. We recommend the same to anyone building an engine. Below is a list of measurements that we routinely make when rebuilding a two-stroke top end:  Piston ring end gaps  Piston-to-cylinder clearance  Rod small end diameter Out of these measurements, confirming or adjusting the ring end gaps is by far the most important, followed closely by ensuring the cylinder bore is within spec with respect to diameter, straightness, and roundness. Understandably, some measurements may be difficult for the average home builder to execute, usually due to not having the right equipment, however, a competent shop should be able to assist. Ring end gaps can be checked by installing the ring in the bore without the piston, and using a feeler gauge to find the measurement. Correct ring end gap is listed in the installation instructions that come with a new ProX piston. ProX rings often do not need to be filed as they are pre-gapped, but it's always a good idea to make sure your end gap is within the provided spec. Piston-to-cylinder is another measurement that should be checked before final assembly. For this, use a bore guage and a set of calipers to measure the bore size. Next, grab a set of micrometers and measure the piston. ProX pistons should be measured perpendicular to the wrist pin, a quarter of the way up the piston skirt from the bottom. Subtract your piston size measurement from your bore size, and you have your piston-to-cylinder clearance. ProX pistons come with a chart on the instruction sheet that shows the range your clearance should be in.    Measuring piston-to-cylinder clearance is a smart precaution to help ensure you won't run into any unexpected issues with your new top end. A final measurement we recommend taking is the rod small end diameter. This is important because sometimes these can get worn out and create free play for the small end bearing, resulting in damage to the bearing and most likely the entire top end. It can be done using the same method as the bore diameter. Compare your measurement to the acceptable range in your owner's manual. Making sure the diameter of the small end of the rod is within spec is often overlooked, but can prevent a serious top end failure. Prep Work Cylinder Cleaning - Once the cylinder has been deglazed or has come back from replating, it should be cleaned one final time. There is almost always leftover honing grit that will need to be removed. To effectively clean the cylinder, use warm soapy water and a bristle brush, followed by automatic transmission fluid or a similar cleaning solution and a brush or lint-free rag. To check the cleanliness of the cylinder, rub a cotton swab around the bore and look for contaminants. Clean the bore until no contaminants are visible on the cotton swab. Any honing grit that remains in the cylinder will facilitate premature wear of the piston rings. A clean, de-glazed, and properly honed cylinder is key to piston and ring function and longevity. Power Valve Function - Cylinders that have been exchanged or replated should have the power valve system reinstalled ahead of final installation. Often times, excess plating can inhibit power valve movement. To correct this, the excess plating must be carefully removed. On cylinders utilizing blade style power valves, the blade position with respect to the cylinder bore should be checked to ensure the blade does not protrude into the bore. Assemble the power valve before installing the new piston and reinstalling the cylinder. Be sure to check that the power valve is moving as it should, and not protruding into the bore. Piston - It is usually easiest to prepare the new piston as much as possible by installing one of the circlips and the ring pack ahead of joining it to the connecting rod. Unless your service manual dictates which circlip must be installed first, choose the easiest installation orientation. Typically, your dominant hand and preferred work orientation will dictate which side you choose to install the circlip on.   It's easier to install one clip and the piston ring(s) before fixing the new piston to the connecting rod. Reference your service manual to determine the correct orientation of the circlip. Usually, the open end of the circlip should be oriented to the 12 or 6 o’clock position. Temporarily install the wrist pin and use it as a backstop so that the circlip is forced to move into its groove. Installing the circlip should be done by hand to limit the chance of deformation. Orient the circlip to the desired position, then push the open ends of the circlip into position first. Be careful not to scratch or mar the wrist pin bore in the process! Once installed, use a pick or screwdriver to confirm the circlip is fully seated and does not rotate. Any circlips that can be rotated must be replaced because they have been compromised and deformed during installation. Make sure to note the orientation of each clip after installation. Some manuals may recommend specific positions depending on the piston, but always be sure the gap is not lined up with or near the dimple(s). Rings - The compression ring(s) will be directional, and the top of the ring is typically denoted by markings near the end gaps. Apply a thin coat of oil to the ring, then carefully work the ring into position, making sure to line up the ring end gaps with the locating pin in each ring groove. Install the ring(s) with the marking(s) facing up, and make sure the ring end gap is lined up with the locating pin in the ring groove. Installation Piston - On the top of the piston, an arrow will be imprinted, which typically denotes the exhaust side of the piston. Consult your service manual to confirm the proper orientation of the arrow and piston. Apply a light amount of assembly lube to the small end bearing and wrist pin bore on the piston, then install the bearing. Align the piston with the small end of the rod, and slide the wrist pin into place. Once again, use the wrist pin as a backstop, then install the remaining circlip into position. Use a pick or screwdriver to confirm it is fully seated and does not rotate.  Don't forget to apply some assembly lube to the ring and piston skirts before assembly! Cylinder to Piston - In most applications, a ring compressor is not required to compress the rings and install the piston into the cylinder. Lightly oil the cylinder bore with assembly lube or engine oil, then lube the piston skirt and ring faces. Prior to installing the piston and rings, confirm one final time that the piston ring ends are oriented correctly to their respective locating pins.   Once the new piston is installed on the connecting rod, apply some assembly lube to the cylinder wall, and carefully slide the cylinder over the piston. Squeeze the ring with your hand as you slide the cylinder on, simultaneously making sure the ring end gap remains aligned with the locating pin. Position the piston at or near TDC then carefully lower the cylinder bore down onto the piston. Use your fingers to compress the ring(s) and ensure the cylinder bore is square to the piston. Feel how easily the cylinder slides over the piston and rings. The installation of the cylinder should be smooth and offer little resistance. If resistance is felt, stop immediately and assess the ring pack. Occasionally one of the rings may come out of position in its groove and snag the cylinder bore. This typically happens as the ring transitions out of your fingers and into the cylinder bore.   Once the cylinder is safely over the ring, slide it all the way on keeping the piston at top dead center (TDC). Don't forget to torque your cylinder and head nuts to the specification listed in your manual. Post Build Torquing - Your cylinder and head nuts should always be torqued to the specifications outlined in your service manual. Double check all the nuts are set at their corresponding specs. Spark Plug - Don’t forget to install a new spark plug and if necessary gap it appropriately. Air Filter - Be sure to install a clean air filter prior to start up. Crankcase Leak Down Test - As one final precautionary measure perform a crankcase leak down test. A crankcase leak down test will help confirm all the seals, gaskets, and joints are sealing as they should. Break-In - When running your new top end for the first time, keep the engine slightly above idle, with slow and mild revs until the engine starts to get too hot to touch. Then, shut the engine off and let it cool until it is warm to the touch. Repeat this process, revving slightly higher and letting the engine get partially hotter each time. After 3 cycles like this, let the engine completely cool, then check all your fluids and re-check the torque on your cylinder and head bolts. Once that is squared away, you can begin break-in runs riding the bike. Make sure to keep the RPMs varied while riding for the first time, not letting the engine lug or sit at idle. A safe bet would be to ride the bike like this for 5 minutes, then 10 minutes, and finally 15 minutes, with adequate cooling in between. This will ensure your piston ring(s) are evenly and properly broken in. It’s never a bad idea to double check your fluids and torque one more time after complete cool down.
    Posted by Rob@ProX on Jun 28, 2018

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