Yz 450 Jumped Time????

2 replies to this topic
  • kamaral26

Posted March 12, 2009 - 08:45 AM


Hey guys so my 450 jumped time which kinda blew my mind but i have a about 120 hours on it so the cam chain was pretty worn i guess. i dont think i bent any valves but how do you know? I replaced the chain and tensioner got the timing dead nuts and the bike started better than it ever has...but there is a new sound i think like a blowing sound its not to loud but loud enuf to hear??? is this normal and i just dont remember it? havent run my bike in about 2 1/2 months? did i just forget this sound or does that mean i messed something up????? Sorry its kinda general but any advice would help camping the first week of april so trying to work it all out now....:)

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  • grayracer513

Posted March 12, 2009 - 09:24 AM


You should replace the tensioner if you have not done so. Be sure the you are at TDC on the compression stroke when you do this.

A leak down test will reveal any sealing problems caused by damaged valves.

If it runs, it can't have bent them very much. OTOH, if one were very slightly bent, it could eventually lead to the valve breaking, and that would not be good. The only way to really tell is to tear it down, but the odds are in your favor.

  • kamaral26

Posted March 12, 2009 - 11:54 AM


yeah i did replace the tensioner, the timing was dead on, and the dealer did a leak down test it was good....so judging by it starting like new and running great i think ill call it good

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