Yamaha WR250R Mega Thread

Discussion in 'Thumpers' started by Sock Monkey, Apr 7, 2008.

  1. freetors

    freetors Long timer

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    Hey guys I'm having a real bad problem with my chain flailing wildly from side to side. It starts doing this from about 45 mph and up but somewhat intermittently. Throttle position seems to have an effect too. It makes the bike feel like one of my wheels is badly out of true. The vibration is causing my headlight shroud, instruments, and mirrors to jiggle side to side rapidly. This side to side play is causing the rear chain guide to wear very rapidly (down to the metal on one side).

    I put on a new chain and sprocket set about 2-3000 miles ago and this problem has just shown up within the last 500 miles or so and it's getting worse. I'm running 14/49 with a renthal sprocket on front and a steel JT on the back with a lower end RK chain with clip master link. The clip is on tight and installed correctly. I've tightened up the chain as much as I dare, about .5" play with the swingarm pivot, axle, and countershaft aligned.

    Anybody ever have this annoying problem before?

    [​IMG]
  2. bhd1223

    bhd1223 Been here awhile

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    Just something that seems plausible, are the sprockets/wheels aligned? Perhaps the rear wheel got knocked out of alignment at some point but not enough to be visibly noticeable. Then the sprocket starts pushing the chain to the sides and begins wearing funny, This misalignment then causes more weird wear on things around it. Just late night speculation on what seems like a simple cause to a recent problem without an obvious cause.
  3. freetors

    freetors Long timer

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    Yes, I forgot to mention that I've checked the alignment. The sprockets are perfectly aligned, chain is arrow straight and not stretched. The axle is exactly the same distance from the SA pivot on both sides- this is measured, not using the axle blocks.

    Front sprocket nut is on tight as are the rear sprocket bolts. I even tried shaking the rear wheel thinking maybe one of the wheel bearing possibly died but it's solid too.

    I wish it was something so obvious :cry
  4. The Breeze

    The Breeze Been here awhile

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    I was wondering the same thing......

    Not sure if they differentiate with the part number....but there is definitely a difference (visually) between the two pumps (old vs. new).

    If you go to "basherdesigns" website, he has a tutorial on replacing his fuel pump, and shows a picture of the old vs. new fuel pumps. A portion of the injection molded plastic on the new pump is "black" (majority of plastic is still white), vs. the old pump, in which the molded plastic is 100% white. Hopefully that makes sense....but if not, check out bashers site.
  5. Heoz

    Heoz Adventurer

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    http://wr250rforum.forumotion.com/t6460-new-fuel-pump - 1st post by railbird in the thread. Turns out that the production date is on the box.
  6. jon_l

    jon_l Long timer

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    Good info. Thanks!
  7. markusarealuis

    markusarealuis Been here awhile

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    coming back from San Anotonio Texas.....to Wako Texas :)
    [​IMG]
  8. Starcha007

    Starcha007 Adventurer

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    I rode in 100+ deg weather and stopped at a store. After I came back the bike wouldn't start and you couldn't hear the fuel pump prime. 45 min later the bike would start up. I just had the 3 gal IMS tank installed without heat shielding and thought that was the issue, but it wasn't. After heat shielding the tank it happened again. My bike is a 2011 with 2300 miles on it and out of warranty. My dealer confirmed that the fuel pump was bad. I asked if they could contact Yamaha about the issue which they did. Yamaha agreed to take over the cost of the new fuel pump and labor. Now my question, did they install older pumps in the newer bikes?
  9. xaman

    xaman Been here awhile

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    Hey markus,

    Congrats! I've been watching for an X in Texas and they are hard to come by, good snag!
  10. indypup

    indypup ╭∩╮( º.º )╭∩╮

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    I have an X in Texas and that's why I stay away...lol
  11. skierd

    skierd Wannabe Far-Rider

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  12. Joe Watson

    Joe Watson Long timer

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    Well, it is now official! I have the ugliest bash plate ever made!!!

    [​IMG]
  13. Subaru297

    Subaru297 Been here awhile

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    I have a very similar problem on my KTM 530. On my bike I think it only happens when I am lugging the bike. It seems to smooth out when I downshift or increase rpm's. I really only notice it shifting into 6th and not going fast enough.
    I have a new chain and sprockets to go on as well. I hope that cures it, but based on your experience maybe not. Sprockets are aligned with the motion pro alignment tool.

    Hopefully someone else knows the solution.

    Cheers
  14. jon_l

    jon_l Long timer

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    Details?
  15. Joe Watson

    Joe Watson Long timer

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    It is a bash plate which I made myself out of aluminium that has two tool box sides to it. The pic is taken at the worst angle, so it does look better than that in real life. Um..... not sure what other details you would like to know..... it is big and ugly and will stop me dead if I ever try to hop a log or go through a deep rut......
  16. indypup

    indypup ╭∩╮( º.º )╭∩╮

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    Maybe not the ugliest but probably the biggest. ;) I guess you could put your feet on top and use it as highway pegs too. ;)
  17. AZ TOM

    AZ TOM Long timer

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    I can't argue with you on this evaluation:D Looks strong & kinda midevil:wink:
  18. jimrobinette

    jimrobinette Been here awhile

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    Joe, nobody could ever accuse you of being a liar! :rofl
  19. Pantah

    Pantah PJ Fan from Boston

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    :rofl

    I'd like some of that ugly, though....
  20. jon_l

    jon_l Long timer

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    I'd love to see the inside.