Need to learn how to check valve clearance

I have a 01 WR426 and need to learn how to check and if so adjust the clearances. Anyone able to help?


What do you want to know, it's really no big deal. D you have a service manual?

Pull the valve cover off, get out the feeler gages, put her up on TDC and start ot measure the clearance. The standard width feeler gages will make it tough, a nicer narrow set, that also have the 30 degree bend in them make things a lot easier.

Checking em is easy, adjusting them takes a little more time and effort, not at all undoable (is that a word). Just that you'll be pulling cams, to get to the buckets and shims. :)

what joe said :D

if u do need to adjust them:

1) make sure engine is at TDC before you do anything

2) if u have a digital camera, take some pics of the cam sprockets before you remove anything. Will help with retiming the camshafts

3) If you want to YZ time your bike, now is the time as it takes no extra time once you have the cams out. (Ex cam retarded (clockwise from sprocket end) 1 tooth)

4) Check everything twice before you screw the tappet cover back on. Kick the engine few a few cycles before you attempt to start it.

If a few valves are out of spec you can sometimes swap shims around so you only need to buy 1 or 2 shims. Write down the clearance of each valve, when u remove the shims measure the thickness with a micrometre. Dont trust the markings as someone may have dressed the shims previously :) Using the table in the manual you can easily see what thickness you will need.

hope this helps,


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