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Found 13 results

  1. I have a 06 ttr 230 that I suspect has a blown head gasket. Does anyone know what the compression is supposed to be?
  2. I have a 2001 YZ250 and do mostly Colorado mountain and woods riding. I have never been able to figure out where to set my fork and shock compression and rebound clicks. I am about 6ft 235 lbs (more with gear on) and all the information I find is for little guys haha. I have tried setting them and adjusting up or down a bit but never found a sweet spot. Does anyone have something that works good for them at a similar weight? #fatguyproblems
  3. Hi everyone, I recently got a 1990 DR250 that had the engine swapped from a DR350, presumably 90-93 model. It was missing the decompression lever and cable, and the previous owner used it that way. I put on a decompression lever and cable, then adjusted the valve clearances. My problem seems that either the decompression lever will work and become engaged by the lever, and click back when it hits TDC but with no compression overall, or I have high compression but the decompression lever does nothing. Ive tried to adjust the exhaust valve to the manual spec and even play around with increasing or decreasing the clearance. So it seems either I can kick it with no resistance and no combustion, or nearly impossible to kick but a sputter hear that it wants to start. Am I doing something wrong, or am I missing something?
  4. Hey guys, My buddy and I just finished rebuilding his 1998 CR250 which we bought with a broken connecting rod. We replaced the main bearings, crank, gaskets, seals, piston, and the cylinder bored and honed to match the new piston. I did a compression test before it ever started and read about 150 PSI. Then we started it. Ran well, but wanted to die whenever we hit the powerband (this is after we let it idle to break in the seals for twenty minutes) anyway it died a couple times always started right back up until it didn't. I did another compression test and got about 90 PSI. I refuse to believe the rings are stuck, but I guess it is possible. I took the head off and the piston looks fine. Oh also we found some small beads of coolant around the head. I ordered another head gasket (OEM) since I read that the tusk head gaskets don't work great. That won't be here until next week so I thought I'd ask you guys if I'm on the right track in the meantime. Thanks.
  5. Hello all... First time here and I hope this is a good area to post this piston head question. I purchased this 2005 KX85 Kawasaki as it wasn't running from the seller, says he couldn't get it started and I've been doing maintenance to it as it was way over do as the carburetor was filthy and the jet were clogged, unclogged clean up carburetor and put back together. So I got around to check the valves from the carburetor side of the piston head looked very good then I removed the bikes pipe and took a photo of the piston head from that end and I noticed a scar or a gouge in the piston head , I really don't think that should look like that. Looking for feedback on what to do next as repait that piton head or can I try to start the bike even thought of this issue with the scar/gouge in the piston head? Any feedback would be helpful. ..
  6. I recently bought a 2001 yz250f and it has 60 psi of compression with 5 moderate kicks. It can only start when I bump start it and when I do it runs fine just doesn’t have enough of the snappy torque a 250 Should have. The person I bought it from put in new valves and a new high compression piston in it and put the old rings back in it instead of the new high compression ones (for no particular reason). When it runs there is no smoke coming from the exhaust so I’m assuming the rings are alright. I’m betting it’s the valves and just want your guys 2 cents on the deal whether you post a link to a previous topic or say what you think it could be. Thanks!
  7. Alright TT Gentlemen.. I appreciate any and all who have commented on my posts, without TT and the knowledgeable people in it, things would have taken me much longer. Anyway, I was shimming my valves the other day,before I did it when I checked the clearance.. There was none. I couldnt fit my smallest feeler gauge between any of the valves and the bucket. both on intake and both on exhaust would not fit. I checked my compression before I did this, and it was only at 60/70 PSI which I know is far too low. Before I tear into the engine, I want to get everything I need.. so if A new piston is in store then so be it.. But would valves that have far too little clearance at TDC cause low compression when cranked? Thanks again guys! - Brad
  8. Replaced the O-rings and bushing on my front forks of my 2000 Honda CR250R. Got to the step of adding fork oil and did all that but when I pump the piston rod to bleed out air I cant seem to get any pressure for the rod to go back down. It goes down about an inch then stops. Still hear sounds of air pressure in the system possibly but Ive pumped it about a hundred times. Manual says if you cant get pressure youve added too much fluid so ive adjusted it and still no progress. Any ideas on what may be wrong o
  9. So I got a 2004 crf150f and it has been ticking so I proceeded to do a valve adjustment and it sounded about the same so I let it be and rode it a few times and it was fine but one day as I was riding it started to bog out on the top end (higher rpms) so got it home, checked the valves again and they were in spec. The intake and exhaust both are supposed to be a .004 inch I tried that I was told to try going a .005 on the exhaust to see if that would work I tried a few different ratios and each time they bike would bog out on the top end when I rode it. I’m thinking maybe a valve bent or something so I did a compression test by just kicking it over idk if that’s how u can do these bikes but I got 120 psi I don’t have a manual so idk what it’s supposed to be someone help
  10. Hey guys. I swapped springs on my xplor 48 forks, and now the compression clicker in the cap turns forever in both directions. Anyone know whats up with it? Is the cap totaly broken and have to replace the whole cap? Or can I try and fix part of it?
  11. With years of performance piston experience, JE knows ring operation is just as important as piston quality. Follow along with our complete guide to installing rings on your motorcycle piston(s). The correct installation of the piston rings is an essential aspect of rebuilding any four-stroke engine. This task is perceived by many to be simple. However, there are vital aspects of ring installation that should not be overlooked. Improper installation of the piston rings can result in limited engine life, reduced power, and high oil consumption. In this article, we’ll walk step-by-step through the ring installation process so that the next time you’re rebuilding your engine, you know exactly what to do and what to watch out for. JE now has pistons available for many late model applications. Find the performance you've been looking for. For starters, never attempt ring installation without the appropriate documentation available for reference. At JE Pistons, comprehensive instructions are included with most new piston kits. This ensures the engine builder has the necessary information available to do the job successfully. The machine’s factory service manual should also be on hand throughout the build so that things like torque specs, service limits, and procedures can be referenced. It's important to read and understand any assembly and installation instructions that come with your pistons. These instructions are for representational purposes only and not valid for all JE pistons. Process Overview Before diving into installation details, a quick recap of the process will be helpful to understand what’s to come. Shown below is an outline of the major steps you’ll go through. Measure ring end gap Clean all rings Mark piston where the end gaps should align Install oil rings Install 2nd compression ring Install primary compression ring Verify groove clearance Not sure which piston ring set you need to order? Check out our guide here. In addition to understanding the steps you'll be performing, laying out all the components needed helps stay organized and prepared. Time for a new piston kit? Find one here! Step-by-step Process Measure Ring End Gap Before installing the rings onto the piston, it is imperative that the ring end gaps are checked and verified against the specs provided with the installation instructions or factory service manual, whichever is applicable. If more than one compression ring is used, confirm any design differences between the two by referencing the installation instructions. Chamfers on the inside edge of the ring or different markings at the ring ends are common identifiers used to denote ring differences. Need clarification on all the markings used on JE rings and pistons? Click here. To check the ring end gap, simply install the appropriate ring into the cylinder bore and position it near the top of the bore. Use the depth rod end of a caliper to ensure the ring is square to the bore. Next, use feeler gauges to measure the ring’s end gap. Carefully insert various thickness feeler gauges between the ring ends until the gauge just begins to drag between the ring ends. Note the thickness of the gauge and compare it to the end gap specifications provided. This process can be repeated for any additional compression rings used. The majority of JE's motorcycle rings are pre-gapped, but it's always good practice to check ring end gap for all compression rings prior to installing on the piston. At JE Pistons, the ring end gaps are preset at the factory to fall within spec when installed in healthy cylinders used for normal applications. The end gap of the first compression ring should always be less than that of the second compression ring. If the end gap specs are outside of range, first double check your measurements and verify the cylinder bore is the correct diameter. Assuming no issues are found with the measurements or cylinder bore and the end gap measured is too tight, the rings can be carefully filed. To do so, use a small file and file one end of the ring. Be sure to maintain parallelism to the other ring end as you remove material. Remove small amounts of material and check the end gap periodically so that you don’t remove too much material. If ring end gap does need to be adjusted, evenly file one end of the ring only in small increments and continue to check until it's at the desired spec. Clean All piston rings should be cleaned before being assembled onto the piston. Before cleaning, confirm the ring ends are free of burrs. Any burrs present can carefully be dressed by gently breaking the edge with a small file. Next, use your preferred parts cleaner to wipe down the rings and piston. Make sure your rings are clean and free of any debris or burrs. Mark the Piston Review the instructions provided with your piston kit, or the guidelines provided in your owners manual if no alternate instructions are provided, and note the specified positions of the ring end gaps. Use a marker to mark the edge of the piston crown with the intended ring end positions for the oil control and compression rings. Doing so will help ensure no orientation mistakes are made upon ring installation. Follow the ring end gap orientation instructions for your specific piston(s) and mark the piston so you know where each end gap should end up. Oil Control Ring Installation Modern oil control rings typically utilize a three-piece design and consist of two side rails and an expander ring. Three-piece oil rings can be challenging to install if the ring design and methodology are not understood. The expander ring is the waffle shaped ring and features a stepped edge on the top and bottom of the ring. The side rails are the two small, thin rings which complement the expander. When properly installed, the side rails sit on the top and bottom of the expander ring against its stepped edges. For this reason, the expander ring must be installed first. The other feature of the expander ring worth paying attention to is its ends. Due to the expander’s accordion-like shape, it is possible for the ring ends to overlap in the ring groove. For proper installation, it is imperative that the expander’s ends butt and do not overlap. The ends of the expander ring should be touching, but not overlapping. To install the expander ring, lightly coat it with engine oil. The expander ring is non-directional, so it can be installed in any orientation. Carefully work the ring past the compression ring groove into the oil ring groove. Adjust the expander ring as necessary, so the ring ends are correctly positioned. Ensure the ring ends butt together and don’t overlap. Start by installing the expander ring after lightly coating with oil. The side rails are also non-directional. Lightly lube the side rails then install them on the piston. Make sure the side rails sit correctly against the stepped edge of the expander ring and that their end gaps are positioned properly. Once the side rails have been installed, double-check the end gap positions of all three rings that comprise the oil control ring assembly. Ensure the expander ring’s ends are not overlapped and ensure the assembly moves freely within the oil ring groove. Oil and install the oil expander rails below and above the expander. Be sure they are resting evenly and the end gaps are lined up with the appropriate markings. Compression Ring Installation If the piston utilizes two compression rings, the second compression ring should be installed first. Refer to the installation instructions to determine the proper orientation of the ring before installation. Typically, dots or letters will be marked near the ring end, which denotes the top of the ring. Internal edge features such as chamfers may also be used to identify the ring and its correct orientation. Lightly oil the ring and then carefully work it over the piston into its appropriate groove. Adjust the ring’s end gap position so that it aligns with the mark you made for it on the piston crown. Repeat this process for any remaining compression rings. Install the compression ring(s) in a similar fashion, lightly applying oil and carefully working the ring around the crown of the piston. Be careful not to twist or bend the ring out of shape as it could affect its ability to seal properly. Confirm Groove Clearance Once the compression rings have been installed, the ring-to-groove clearance should be checked. To do so, insert a feeler gauge between the ring and groove. The clearance can be identified by finding the feeler gauge that drags ever so slightly between the ring and groove. Note the groove clearance and compare it to the specification provided in the installation instructions or factory service manual. One of the final measurements to take after the rings have been installed is compression ring to groove clearance. Use a feeler gauge for this and find the size that has slight drag. Compare this spec to what's outlined in your instructions or owner's manual. At this point, ring installation onto the piston is complete, and subsequent steps can be taken to complete the engine build. While installing the piston rings onto the piston is a critical step in the build process, it can be performed by anyone when the proper steps are taken. The process simply requires the correct measurements are taken, cleanliness is ensured, and installation techniques are used. In search of a quality, performance forged piston for your bike? Click here to see what's available for your machine.
  12. When it comes to overall strength, there's no beating a forged piston. But what is the process that yields the toughest parts in the racing world? We'll show you. When it comes to turning raw metal alloys into useful things, two processes dominate - casting and forging. Both have their place, but when strength and light weight are priorities, forging is the method of choice. Though it’s been around for more than six millennia, forging processes continue to advance the state of the art, bringing us everything from sharper, more durable kitchen knives to more fuel efficient jet engines, plus things much closer to our heart: lighter, stronger pistons. Although forging is a metalworking process thousands of years old, it’s still the best method to produce components with the highest strength and durability. Forging is defined as the controlled deformation of metal into a desired shape by compressive force. At its most basic, it’s a blacksmith working a piece with a hammer and anvil, and those first metalworkers toiling at their forges discovered something important about the pieces they were crafting – compared to similar objects made from melted and cast metal, they were stronger and more durable. Though they knew the finished product was superior, what those ancient smiths didn’t suspect was that the act of forging was changing the internal grain structure of the metal, aligning it to the direction of force being applied, and making it stronger, more ductile, and giving it higher resistance to impact and fatigue. While a cast metal part will have a homogeneous, random grain structure, forging can intentionally direct that structure in ways that give a finished part the highest structural integrity of any metalworking process. Wiseco forged pistons start as raw bar stock in certified 2618 or 4032 aluminum alloy. Once they’re cut into precisely-sized ‘pucks’ they’re ready to be preheated in preparation for forging. Although many performance enthusiasts might put billet parts at the top of the heap in terms of desirability, the reality is that the billet they are created from doesn't have the same grain properties of a forging. The Wiseco Forging Process Today’s state of the art in forging technology is far removed from the smith’s bellows-stoked fire and anvil. In Wiseco’s ISO 9000-certified forging facility, pistons begin life as certified grade aluminum bar stock, cut to precise lengths to form slugs. The choice of material is critical - conventional wisdom has always said that a forged piston requires additional piston-to-bore clearance to allow for expansion, leading to noise from piston slap until the engine gets up to temperature, but per Wiseco’s Research and Development Manager David Fussner, “Forged pistons do require additional room temperature clearance. However, the 4032 forging alloy we use has about 12% silicon content, and this significantly controls the expansion to nearly the same as a 12% silicon cast piston. The 2618 alloy expands a bit more and does require a bit more room temperature clearance than 4032.” Pistons are forged in a ‘backwards extrusion’ process where a moving punch presses the raw material into the die to form the rough shape. The process takes only a fraction of a second (longer in the isothermal press), and the speed of the press helps determine how material flows, and therefore the internal grain structure of the forging. While 4032 is more dimensionally stable across the typical operating temperature range seen inside an engine, it does give up a small advantage in ductility to 2618, which has a silicon content of less than 0.2 percent. This makes 2618 a better choice for applications where detonation may be an issue, like race engines running high boost or large doses of nitrous oxide. The low silicon alloy’s more forgiving nature in these instances makes up for the tradeoffs in increased wear and shorter service life compared to 4032. Once cut to the proper size, slugs are heated to a predetermined temperature and moved to the forging press itself, which is also maintained at a controlled temperature. There are two different types of presses employed at Wiseco; mechanical and hydraulic. Both have a long history in manufacturing, and each has specific strengths. Mechanical forging presses are well-suited to high production rates, helping to keep the overall cost of high-quality forged components affordable. Hydraulic presses have the advantage of variable speed and force throughout the process, allowing greater control of material flow, which can be used to produced forged components with even more precisely controlled physical properties. Wiseco’s isothermal hydraulic press forging machines use precise digital control of the temperature of the raw material, the punch, and the die, as well as the pressure exerted during the full motion of the forge. This allows very close control over the physical properties of the finished forging. Regardless of the type of press, pistons are forged using a “backwards extrusion” process where the material from the slug flows back and around the descending punch to form the cup-shaped forging. Picture the stationary part of the press (the die) as the mirror image of the piston top, and the punch as the mirror image of the underside. As the punch descends, the puck is transformed into the rough piston shape with material flowing up along the sides of the die and punch to form the skirt. This entire process takes place on the scale of milliseconds (on the mechanical press), and the all-important flow stresses of the material are determined by the strain rate (or speed) and load applied by the press. In addition to three mechanical forge presses, Wiseco also has two isothermal hydraulic presses in-house. These state of the art forges maintain the temperature of the piston slug, the die, and the punch very accurately through computer control, delivering more precise dimensions and geometry for the finished pieces, as well as allowing for more complex designs to be successfully forged, and even the creation of metal matrix composite forgings. Once the puck (left) has been transformed into a forged blank (middle), it still has a ways to go before becoming a completed piston (right). The Heat Is On Once the forging process is complete, the components next move to heat treatment. Wiseco’s aerospace-grade heat treatment facility is located in the same plant as the presses, and here the pistons go through a carefully controlled process of heating and cooling that relieves stress induced during forging, increases the overall strength and ductility of the metal, and provides the desired surface hardness characteristics. While casting can deliver parts straight out of the mold that are very close to their final shape, forgings require a bit more attention in order to get them into shape. Fussner explains, “In a dedicated forging for a specific purpose, the interior of the forging blank is at near-net as it comes off the forging press. And in some cases, we also forge the dome near-net with valve pockets and some other features. Other than these items, most other features do require machining.” Pistons aren't the only thing Wiseco forges and machines in-house. Wiseco clutch are also forged and machined, as well as finished with hard anodizing. The forging (left) allows the basket to closer to the final shape before machining. The basket shown here is just post-machining. One basic forging may serve as the starting point for many different types of finished pistons, unlike castings which are typically unique to a single design or a small group of very similar designs. Regardless of the manufacturing method for the piston blank, some degree of final machining needs to take place to create a finished part. “As a ballpark percentage, I would say about 75% of the forging blank would require machining.” Cast pistons also require finish work on the CNC machine, but this is almost always less extensive than a similar forged piston. “That’s the main reason why forged pistons are more expensive than a cast piston,” Fussner adds. Another reason for the added expense of forging is the significant cost of the initial tooling for the die and punch, which must be made to exact specifications and be durable enough to survive countless forging press cycles. Per Fussner, “We control these costs by making all our forging tooling in house at Wiseco headquarters in Mentor, Ohio.” The ability to make their own tooling, doing their own forging, and their in-house heat treatment facilities make Wiseco the only aftermarket forged piston manufacturer in the United States with these unique capabilities. Once the machining process is complete, Wiseco pistons can also receive a number of different proprietary coatings to fine-tune their performance. These include thermal barriers as well as wear reduction treatments. Though forging is a technique literally as old as the Iron Age, it’s still the undisputed king of manufacturing techniques for light, strong, durable components. Wiseco continues to refine the process with the latest methods, materials, heat treatment, and machining to provide the highest quality aftermarket components available, at an affordable price. Wiseco forged pistons provide superior quality and performance at an affordable price thanks to the company’s close control over every step of the manufacturing process.
  13. I have a 1998 cr125, and it seemed to be low on power and compression (just judging by kicking it over and riding) It also got hard to start. The starting and running could be because indiana winter weather. I borrowed a compression tester and got 120 psi (I read it should be 140-185) I didnt want to blow the bike and have to replate the cylinder, so I pulled it and checked ring gap. It came out to be .014" which seems fine. It has a 53.94mm namura piston (not my first choice but it's what came in the bike) and there is still cross hatching on the cylinder. Why is the compression low, and how can I fix it?
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