Reshim with auto decomp cam???


7 replies to this topic
  • dmoney1074

Posted March 22, 2007 - 12:43 PM

#1

If my valves are in spec now, will I have to reshim after installing the 03' yz450 ex cam??

Thanks, Dan

  • devo1

Posted March 22, 2007 - 01:21 PM

#2

If my valves are in spec now, will I have to reshim after installing the 03' yz450 ex cam??

Thanks, Dan


If it is a 426, you will have change the shims.

  • clark4131

Posted March 22, 2007 - 04:36 PM

#3

If you're doing a cam change, you may not need to re-shim, but you have to check your tolerances to be sure...SC

  • dmoney1074

Posted March 22, 2007 - 04:39 PM

#4

Should I just throw the cam in, bolt it down and then check? Or should I run it then check? I know it sound stupid but thanks!

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  • SXP

Posted March 22, 2007 - 04:46 PM

#5

If my valves are in spec now, will I have to reshim after installing the 03' yz450 ex cam??

Thanks, Dan


To add to Devo's post above, if its a 400 OR 426 you will have to reshim with thicker shims - in the range of 1.95 to 2.05 mm if I remember correctly. Of course that will depend on how much your valves have already settled into their seats - thicker if there hasn't been much settling, thinner if there has. Dunno about the 450s - but probably not.

  • Birdy426

Posted March 22, 2007 - 06:38 PM

#6

Should I just throw the cam in, bolt it down and then check? Or should I run it then check? I know it sound stupid but thanks!


You will have to shim...the base circle on the 450 cam is a bit smaller than the base circle on the 426...lift, duration, overlap, etc are the same.

Put the cam in, measure and reshim BEFORE you start the bike up...don't run it first. After you get it shimmed up right, run it for a bit, then check the clearance again.

  • byggd

Posted March 23, 2007 - 04:20 AM

#7

If my valves are in spec now, will I have to reshim after installing the 03' yz450 ex cam??

Thanks, Dan


Yes you will. Take a look at steps 2 & 3.

http://s18.photobuck...0cam_Page_1.jpg

  • RallyImprezive

Posted March 23, 2007 - 08:12 AM

#8

Might as well check the intake too while you are in there. I figure if im going through the trouble to take stuff apart, I might as well replace as much as I can.




 
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