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  1. i am just wondering if anyone out there has big bored a 250x and if any one has put in a hotcam stage 2 cam also. also how much power this resulted in. thanks! http://www.crfsonly.com/catalog/product_info.php/cPath/26_110/products_id/1828
  2. I'm working on rebuilding a 2001 YZ250 from the crank up and am having a problem with the top end going together. When I snug down the cylinder, the piston locks up with, or without the rings on it. I can also move piston around in the cylinder but it won't go up and down. There's 2 5/16" on both sides of the rod, so the crank appears to be centered. Specs: New Hot Rods crank and bearings New Wiseco piston Cylinder was serviced by Millenium Technologies. Has anyone had this problem before or know what it might be??
  3. If I understood right from some threads I found here changing clutch plates requires to drain coolant? my question is then is it doable changing clutch plates on the trail not having oil and coolant? just putting a bike on the side and do it that way so nothing would drip off? Anybody here had to do it not in garage?
  4. 2007 KX250F First time adjusting valves, I'm putting it back together, I set the cams correct, camshaft covers on tightened down, I set the Cam Chain on the Cam gears at TDC, installed the cam chain tensioner then tried rolling the crank to get ready to check valve clearance, and it's so tight it will not rotate with the ratchet!! Has a lot of resistance and I'm confused on what to do next!? I believe the Cam chain is on the bottom gear, it rotates fine off the cam gears when I hold the chain and crank the engine, it looks like it's on from what I can see. Then I put the chain back on the gears with the tensioner out, it's loose, tighten the tensioner and chain feels very tight no slop in it and try to crank engine with the 14mm ratchet and it is so tight I'm having trouble...
  5. My bike is an '07 and it started to leak from the weap hole, I have the right engine cover off with the bearing in the case visible. Still need to remove the gear and shaft to see the bearing and seal for the weep hole on the engine cover. I started trying to remove the one in the case first.. not entirely thinking about it, I just figured that was one of the bearings im going to be romoving.. ( I didn't follow instructions properly.. Also didnt pay attention..) I tried the bar in the shaft behind the inner race and tapping. I beleive I did more harm than good.. It feels a little wrontchy when I spin it now. there are a few scratches behind the inner race from what I can see and it will not budge.. there are some photos I attached below, one is of the bearing in the case, the other is of the gear and shaft, also the seal and bearing location on the engine cover. At this point I'd like to leave it and just replace the seal and bearing on the gear shaft. since I might have damaged the bearing (in the case) would I need to go ahead and replace it or would it hurt anything to leave it? if I need to replace it since I've already messed with it, do I just need a bearing puller to get it out? one other question.. Is the bearing in the case connected to anything other than the water pump shaft?
  6. Hi everyone. Hoping to get some feedback on others' experiences with no toil air filter oil. Here's the scoop. I've used Bel-Ray air filter oil since I was taught how to prep an air filter years ago. Since that day, I've had four bikes over the course of the last 8 years and have never had a bike blow up or have any dirt get past the filter, no matter the conditions. A few months back, I spent some time riding out in Ohio where a friend of mine mentioned that he had great luck with using the biodegradable no toil air filter oil and grease and that it made cleaning filters boatloads easier. I figured I would give it a shot and after the first use I was hooked because of how easy cleaning filters became (no toil powder and warm water). After using it on my '11 CRF450 filters for several months, I was very satisfied and even did some recommending of my own on the stuff. I decided to part ways with the 450 and bought a brand new '14 YZ250 when I came home to Massachusetts. Well, my YZ didn't last more than 4.7 hours before she blew and low and behold, sand got past the filter and had some fun in the cylinder. So my question is, has anyone else had problems with the biodegradable no toil filter oil that I'm mentioning? In my own opinion, I'm thinking that the hard packed Ohio dirt made for great air filter results upon my initial experiences with the product, but the fine sand of the tracks here in MA had something else in store for putting the oil to the test. Since my bike blew and I've sought out every opinion I can from other riders, I'm getting "Oh yeah that no toil stuff is junk" and I'm wondering if others can attest to that. I know some may say "well maybe you didn't grease enough or oil enough" or "maybe the oil settled to the bottom of the filter cause it sat" but I can assure you the filter (which was done the day of my ride) was oiled and greased just as well as any filter I've done over the last 8 years. Just looking to hear others' results! Thanks in advance! (This is the result. 4.7 hours.... this hurts)
  7. Hey guys, My new cr125 has a coating of red paint on the cylinder. I'm not sure if it's normal paint or powder coated but I would like to remove it. I have been told to just grab a can of paint stripper and see if that does the trick. My question is, can I use the paint stripper with the bike still together? I'm fairly new to the dirt bike world and not sure I want to take on the task of removing the cylinder only to strip some paint. Would it be possible to cover the surrounding areas with a rag or paper towels, remove the expansion chamber, and use a tooth brush or something to apply the stripper in hard-to-reach areas? Thanks, Will
  8. Hi i need to buy some engine parts for my dirtbike and the engine used is yamaha but not the bike. The bike is from spanish manufacturer rieju. It uses yamaha engines and i read in forums that it uses wr450 engines. I tried and talked to the dealer and he told me he isnt sure about the engine year but told me it might be the 2009 wr450 engine. I just wanna be sure before i splash cash in it.Any help and suggestions are highly appreciated. I have attached the images below.
  9. My output shaft on my 2007 klx110 was broken so I split the cases replaced the shaft and put the cases back together. Every turned smoothly, until I tightened the crank case bolts. When I tightened the crank case bolts, the crankshaft became hard to turn. The more I tightened the bolts the harder it was to turn the crankshaft. I can’t seem to figure it out and I think I have literally split the cases 15 times by now! Any possible solutions would be much appreciated, Thanks!😶🤔
  10. Have a 2003 rm 125 on the first ride it seized bad crank bearing changed the crank and bearing and gaskets first ride after being fixed there started to be a weird grinding sound coming from bottom end almost sounds like clutch side bike starts and runs fine im not starting it though to minimize damage
  11. Just bought a 2000 KX 250 two-stroke for a great deal when looking for a project bike. When I put the bike in neutral which is a little hard to find, it jumps into first gear by itself and trys to takeoff no matter if I squeeze the clutch lever or not. When I first started the bike it basically did a burnout in my garage with no throttle applied and the clutch lever pressed then it just stalls out eventually this happened for about five seconds. Attached are some pictures of my clutch disk and clutch basket from what I researched today the basket should not look this bad , but do you guys think? Is the clutch the source of my problems or is it something internal and would I need to split the case.
  12. Attn all engine builders... I have a 2015 YZ250FX with 200 hours. Replacing the top end and cam chain right now. I checked gaps and play on the rod and crank and found the following: ✅ Gap between rod and crank is within spec. Tiniest side to side sliding movement along lower bearing ❓ Rod does seem to rock side to side (not just slide side to side) when pushing sideways at the little end. No spec on this, not sure what is acceptable (very tiny, hard to even detect) ✅ Rod does NOT have any play whatsoever up and down on the crank. (no click or perceivable movement when pulling/pushing rod against crank lower bearing) ✅ Crank has no play whatsoever when pushing the shaft in/out of the case, side to side (bearings seem ok in this regard) ✅ Crank (from the flywheel side) shows no play whatsoever moving forward and back, horizontal. (no tension applied by cam chain, of course) ‼️ Crank DOES show a very tiny but perceivable amount of play vertical, up/down within the case (at TDC, and when I rotate it 90 deg from TDC, the play is still only up/down, does not follow the orientation of the crank, is always vertical relative to the case) Pic illustrates what I mean. Green arrow all good, no play in this direction. Red is the vertical play I am detecting. So everything seems to check out except that last bit - has me worried for sure. I could not find my dial caliper to measure exact play, but in the meantime... How much play is acceptable here, if any? (is this normal?). How can there be play in only ONE direction on a round bearing? Does this mean my case has a problem? What is the likely cause? ack!
  13. First time post but I read ThumperTalk a lot. Just got this 2002 YZ125 after not riding for 10 yrs. I'm 28 now. Drove 2 hrs to get the bike, the guy asks me to text him 30 mins before I get there. When I do he mentions the bike wont start but he rode it yesterday. Apologizes. I get there and talked him down to $1100 since I can't hear it run and drove all that way. Get it home and put in new piston and rings and replace crank seals since there was oil in the cylinder. Also replaced the silencer packing as it was drenched in oil. Let it warm and cool three times. Not even 10 mins on the first real ride the ring gets stuck on the exhaust side. Check the jetting to see if it was too lean and realize it's a 1998 carb in a 2002 bike. The previous owner put 2002 jets in it. Put the correct jets for a 98 in it with a new piston and ring and the ring gets stuck again. Then I notice the bridge where the power valve is has no plating on it. Explains the piston problem. Had a 2001 cylinder from back when I used to race. Got a new piston and ring and put it on but realized they changed the power valve design. The old design fit in the new cylinder so I put them in. Made sure the timing was 20 thousandths below top dead center. Ran it and blew a hole in the piston within 5 minutes. Figured the old style valves weren't sealing right so I ordered some 2003 valves off eBay. Put them on and did a leak down test. The valves leaked so I plugged the hose and with 7 psi found a leak at the crank seal on the timing side. After running the numbers I figured out the case is a 1998 model, carburator is a 1998 model, frame and suspension is 2002, cylinder is now a 2001 model with 2003 power valves. The previous owner had a 2002 crank in it because the 1998 seals I ordered wouldn't fit and the 2002 seals I ordered when I first got the bike did. Then I notice after splitting the case to clean the parts of the piston out they must have grinded on the crankshaft where the seals go. Could a small leak where they made the shaft not a perfect circle cause this type of damage that quick? This is my last theory. I've only had the bike 1 1/2 months and spent over $1500 on parts after buying the bike for $1100. Any help is appreciated, I just want to ride.
  14. I just put one in my 04 200 to replace the used and abused Wiseco that's been in there for probably 100 hours. I went with a cast Pro-X hoping to reduce piston slap and have a quieter running top end. Looked alright coming out of the box although the oiling holes for the exhaust side were drilled too close together putting them entirely inside the exhaust port. Won't do any good in there. Since the Wiseco has the same problem but to a lesser degree I wasn't going to worry too much. I filed some oil retaining grooves into the skirt and went ahead and put it in. As soon as I started it up I was disappointed to hear that it was just as noisy at idle as the worn out Wiseco I just replaced. Taking it down the road brought out an alarmingly loud noise under load up to about mid RPM, at which point it ran quiet. The most severe piston slap I've ever heard. Sounded like the piston hitting the head. I was not sure if I could run this thing all week making that kind of noise while I waited for a new set of rings for the Wiseco to show up. Took it to work today and this evening I pulled it apart again. Good thing I did. The piston had begun to gall on the intake side and there was already a considerable amount of the grey muck that used to be aluminum on the piston skirt pooling inside the crankcase. This thing was getting worse quick and would not have made it a week. Looking at the wear pattern on the skirt only about half of the piston was making contact with the bore on the intake side. Beyond the vertical wear marks from the intake bridges there was no contact further out to the side. After reinstalling the Wiseco that came with the bike when I originally purchased it last year, it runs very quiet and smooth. No audible slap. That's what I expected from the cast piston. The Wiseco that came out last weekend has seen some serious thrashing and I am definitely satisfied with the life I got out of it. I won't bother with anything else again. The Pro-X seems to have about .020" clearance in my spare KDX cylinder. I don't know if this thing would work in one of the older air cooled motors or what. Did not work at all in the H series KDX motor. Hopefully Rocky Mountain will give me my money back on this thing.
  15. After a fresh replate by millennium technologies (they had access to this new piston for sizing), a new wiseco piston with proper exhaust bridge holes drilled, new wrist pin and bearing, and new power valves, my 2001 rm125 has a rattling sound coming from the engine. This bike is seriously testing me. It hasn’t given back what I’ve put into it in the slightest. Someone please help me diagnose this noise. I have a video of it running in this YouTube link: https://youtube.com/shorts/sBJHr1Bg7iQ?feature=share
  16. So I have a 2002 YZ 250 that’s torn down for full restoration. I just had the bottom end rebuilt and when I got the motor back from the shop decided to clean it up. I used a dremel and brass wire wheel to clean it up and it looked great till the oxidation started. I wasn’t thinking about whatever protective coating Yamaha had applied 19 years ago. What can I do at this point to make it look right?
  17. I have 2, a 95' & a 97' xr600r. It's time for complete rebuilds. Anyone know of any complete kits available or the best way to source parts?
  18. Ignore my previous post on this topic. I just acquired a 1998 kx250 roller that just needs a motor. Does anyone know what year motors will bolt right in with no issues? Also I noticed there’s a wiring harness on the carb. Can someone enlighten me on what this is for?
  19. 3 reviews

    So amazing upgrade with the camshaft
  20. 2 reviews

    GENERAL INFORMATION Over sized intake valves to suport the BB/stroker
  21. 21 reviews

    Save yourself thousands in costly repairs! The ThumperTalk Manual Cam Chain Tensioner (MCCT) is designed to replace the automatic and hydraulic tensioners found on today's hi-performance 4-stroke engines. Factory automatic adjusters can back out when the throttle is suddenly closed at higher rpms. This allows the cams to momentarily go out of time and can result in bent valves and/or serious engine damage! Hydraulic tensioners have a tendency to put too much tension on the chain guide under high rpm/high oil pressure conditions, resulting in premature cam chain wear. Installation of a ThumperTalk Manual Cam Chain Tensioner will allow you to maintain the proper, constant cam chain tension necessary for reliable hi-performance riding and it will not backout. This is a high quality product, proudly made in the USA. There are thousands of these units in service, so buy in confidence! Precision machined billet aluminum body Oring seals, both on the body and threads Stainless steel adjuster bolt & locknut Clear anodized body for long lasting good looks
  22. 1 review

    CNC machined from 6061 T6 alloy Laser etched logo Distinctive laser etched machined Yoshimura Magnasonian finish Kit Includes Crankshaft Inspection Plug and the Small TDC Plug
  23. 2 reviews

    XC Rings - Replacement Rings Sold per cylinder Wiseco rings fit Wiseco pistons only For +.010 oversized pistons
  24. 10 reviews

    All pistons are heat treated with a T-5 hardening and tempering cycle All piston skirts are coated with a high-tech Molybdenum Disulphite coating for faster break-in time and increased piston life Cast piston kits are gravity cast aluminum alloy (not forged) with 18% silicone content, which produces an extremely light but very strong piston Forged pistons are forged from 2618 aluminum for superior strength and durability Forged High Compression pistons improve power and torque across entire rpm range Big Bore pistons increase engines displacement, torque, and peak horsepower Forged Replica pistons are forged OE replacements Replica pistons and all rings are OEM replacements Kits include piston, rings, wrist pin and circlips Replacement two-stroke piston rings sold individually; four-stroke piston rings sold as a set
  25. 2 reviews

    Upgrading to a high-pressure 1.6 BAR (23 psi) from the stock radiaotor cap is the simplest and least expensive way to avoid over-boiling your engine Raising your cooling systemss maximum operating pressure increases your coolants boiling point, allowing your to ride harder and longer Chrome finished cap Universal fit for most machines High-temp corrosion-resistant silicone seals
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