Need help installing YZ cam!

2 replies to this topic
  • RatRacer

Posted April 19, 2004 - 08:29 PM


I'm installing the YZ450 cam into my WR & I'm a little confused by the alignment marks. First of all when I get TDC on the crankshaft the alignment marks on both the exhaust & intake cams haven't quite gone far enough. When I put the YZ cam in should I just put it in the same spot (incidently putting 14 link pins between upper cam marks) or should I go by the book & align with top of head, then do I also advance the intake cam as well? If anyone has done this before your advice would be greatly appreciated:)

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  • yamaha.dude

Posted April 19, 2004 - 10:34 PM


send me a PM with your e-mail address and I will send you some info...



  • The_Missile

Posted April 19, 2004 - 10:47 PM


rat racer, when I did this I went by the photo I got from this site.
Instructions and Photo of YZ auto decomp cam installation on wr

First ensure your intake timing is correct (if you havent change this its ok) then look at the picture. Easy.

When measuring the gaps on the valves make sure you DONT measure with the decomp bump in place as you will get false readings. You need to rotate the cam so the decomp bump is NOT actuating the valve. I went crazy trying to figure out why I jumoped from 160 to a 190 and my gap was still approx the same. Obvious if you do this kind of thing often but for a newbie mechanic.

good luck.


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