'07 YZ450F valves


3 replies to this topic
  • jbehunin

Posted November 01, 2008 - 02:27 PM

#1

I was measuring the valves on my 2007 YZ450F this morning and saw that the exhaust valves were a bit out of spec. The intake valves were fine.
The exhaust valves, according to my manual are to be about .25, and mine were at .17.

I had a 170 pads in there, but what number pad should I get to put it back in spec? I have asked every mechanic I know, and they said to just toy with it and see what happens, but I dont want to tear apart the bike just to see what will work and what wont, plus those things are 6 bucks each!!!!

Thanks for any info you can share with me.

  • grayracer513

Posted November 01, 2008 - 03:07 PM

#2

Your valves are at .17mm, and the minimum is .20mm, so they are how far out of spec?


Then, if we need to increase the clearance, do we need a smaller, or larger shim?

Good. Now, since your current shims are 1.70mm, what size in .05mm increments will make the clearance fall within the correct specification of .20-.25mm?

Answers to come.

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  • grayracer513

Posted November 01, 2008 - 03:32 PM

#3

> 1) The valves are .03mm out of spec.

> 2) Smaller. A smaller shim will reduce the assembled height of the valve stem/lifter and increase clearance.

> 3) 165. A 165 shim measures 1.65mm, .05mm smaller than the 170, increasing clearance by .05mm. Since the current clearance is .17, increasing it by .05 will make it .22mm. .22mm falls squarely between the specified minimum and maximum of .20-.25mm.

:worthy:

  • jbehunin

Posted November 01, 2008 - 04:14 PM

#4

> 1) The valves are .03mm out of spec.

> 2) Smaller. A smaller shim will reduce the assembled height of the valve stem/lifter and increase clearance.

> 3) 165. A 165 shim measures 1.65mm, .05mm smaller than the 170, increasing clearance by .05mm. Since the current clearance is .17, increasing it by .05 will make it .22mm. .22mm falls squarely between the specified minimum and maximum of .20-.25mm.

:worthy:


THANK YOU!!!!!!!





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