Question about 2003 Yamaha YZ 250

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2003 yz 250 will not idle rattling noise in 1st gear

The bike seems to run strong when throttled up, but when its in 1st gear and im slowly strolling along theres a rattling noise somewhere down below me. It seemed to happen when i had it opened up, and stopped quikly by using the back break, after that is when it started happening.

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  • akelly000 Jul 31, 2009

    It was slack in chain. Thanks

  • ZXP14X May 11, 2010

    need more info. Can you reproduce this with the bike secured & running on a stand? Check for anything loose, clips, clamps, fasteners, levers. but since you say it wont idle, Check your YPVS (power valves). make sure everything is tight, the little bracket screws are all in, and the side cam's can move free. also go back to basics, check compression. When was the last rebuild? Note: no timing chain on a 2-stroke! :)



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Check if timing chain is not loose. If u found the timing chain is loose check your timing if might jumped one tooth of the gear.

Posted on Jul 26, 2009


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Top rating for this answer? Thanks!

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