426 Valve Adjustment?

2 replies to this topic
  • sky-bot

Posted September 04, 2007 - 08:35 AM


I rode my bike this last weekend and noticed that while cruising at a constant speed the motor would miss very slightly every once and a while, does that sound like a valve adjustment issue? or something with the carb?

the bike is a 01 yz426, I have never adjusted the valve in the bike yet and was wondering if any one know of any links or threads that outline the procedure?


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  • grayracer513

Posted September 04, 2007 - 09:38 AM


Your miss is an ignition or jetting issue.

Check the common threads sticky near the top of the index for this forum. There's a valve adjust how-to there.

  • gsk1968

Posted September 04, 2007 - 06:34 PM


I agree with grayracer, if you want to check the valves, it's fairly simple. Original owners manual is very clear. Here's a quick run down. Remove tank and top motor mounts, be sure all area is clean and pop the top(remove valve cover) turn engine to T.D.C. and put the feeler gauges to them.
front exhaust between .0079 & .0098 in. rear intake between .0039 & .0059 in. This according to 2001 manual, got mine on ebay. good luck

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