Yz426/wr450 cam swapping

3 replies to this topic
  • mattyvd69

Posted December 04, 2015 - 05:21 AM


Hi, does anyone know if either or both cams from an 05 Wr450 will work in a yz426? Looking for auto decompression and a mate is selling them cheap. Tia

Edited by mattyvd69, December 04, 2015 - 05:59 AM.

  • grayracer513

Posted December 04, 2015 - 08:57 AM


Both cams won't work because you wouldn't have a reference to time them.  The exhaust cam might work (the YZ450 cams do IF they're timed right), but the WR cam set will also cut your power back considerably.


If you're looking for auto decompression, the simplest thing is the stage one exhaust cam only from Hot Cams, or another, made for the 426.

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  • mattyvd69

Posted December 04, 2015 - 02:02 PM


Wouldn't it just have wr timing on both cams? I always thought the intakes were timed the same but exhaust were a couple of teeth different? I wasn't aware there was a big power difference between yz and wr, just a softer hit

  • grayracer513

Posted December 04, 2015 - 07:45 PM


There's a major difference in power. About 8-12 in the older bikes.  Lots more on later models.


Your understanding of the comparison between cams on earlier is correct.  WR's ran the same cam grind as the YZ but the exhaust cam is advanced about 20 degrees. 


It's about the same on the first 450's, too, but here is the problem: You cannot fiddle with the timing on the auto decomp cams like you could the older ones because one tooth either way will either give the bike so much compression that you can't start it, or so little that it won't run. That's because the decompression pin is basically a retractable cam lobe, and when you change the camshaft timing, you change the decompression timing, too.

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