need help with valve lash adjustment 07 yz 450

2 replies to this topic
  • danimal95

Posted March 20, 2011 - 04:07 PM


a few weeks back i high sided and broke my collar bone,the bike was running on its side for afew minutes before a friend was able to kill the motor,that being bike always seemed mechanicaly loud too me but after the crash (2 weeks later)i threw my leg over it again for the 1st time since the wreck and when i startde it i noticed a dulll tap,(i would compare it to a lifter or rocker arm tap in a car engine) but it was only present at idle and the worst part is,is that i dont recall if it was always there or if im just being paranoid about it running on its any event i decided to do some checking into it before it tuned into a big problem.

i brought it home and started doing some research,alot of people online were saying that noise is common in these engines but more often than not it is a stertched timing chain and worn tensioned,so those being cheap parts i just ordered them figuring that it was apart may as well change after tearing it down i decided to check the valve lash,the exhaust side was right in spec accordin to the yami manuel,the intakes however were different,only 1 was within spec and the other 2 were too tight,is this common?essentially it is hanging open 2 of the intake valves,it is as simple as re-shimming or do i have other issues going on?thanks in advance

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  • Flagstaff

Posted March 23, 2011 - 10:19 PM


Shim per specs, yes these engines are noisy.

  • MANIAC998

Posted March 24, 2011 - 04:57 PM


I wouldn't worry to much about the bike having been on its side. The engine is fed pressurized oil that is squirted to all critical areas, so running on it's side won't hurt it any. Just re-shim it to Yamaha specs and you should be good to go. Maniac


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