Valve check/adjustment

5 replies to this topic
  • gdm

Posted September 04, 2006 - 09:48 AM


Are their any tutorials on checking/adjusting the valves for the WR450?

  • Just_a_trail_rider

Posted September 04, 2006 - 11:47 AM


yes, there is a perfect one.

  • OneToGo

Posted September 05, 2006 - 05:56 AM


....or you can follow the manual.
valve clearance checks are easy..shim replacement more involved..

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  • 123BigcoopDawg576

Posted September 05, 2006 - 06:36 AM


what are shim replacements

  • Gadsen

Posted September 05, 2006 - 08:22 AM


what are shim replacements

This is the next phase after the check. If a valve clearance is out of spec, it needs to be corrected. Too little or too much can rob power, create wear or damage a valve. Much more involved than the initial check. Map out all your clearances. Do this with a stone cold engine. Draw the valve layout on paper, measure all clearances. Then compare to "specs" and now figure the difference. Next phase, change shims to get back into specs. The WR uses a "shim under bucket" design and requires cam and bucket removal to get to the shims. Now you will need to measure the shim that needs changing, then figure thicker or thinner. Thinner will increase clearance, thicker will reduce clearance. Normal wear will usually be too little clearance as the valve wears into the seat, making the valve stem grow in length. But a stretched valve will do the same thing. Excess clearances is a sign of abnormal wear in some cases. If you have excess clearances, look for abnormal wear, ie galling on the lobes, cam journals, buckets etc.

  • JSanfilippo

Posted September 11, 2006 - 09:08 PM


what are shim replacements

Its something you wont have to worry about for a long time. WRs are like TT-Rs in that they require valve adjustments once in a blue moon


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