Will YZ450 03 Cams fit in 01 WR426

Hi I have an 01 WR426 and am able to get hotter cams at the right price, standard cams are overpriced, I want to have auto decomp for easier starting but was wondering in all the wisdom here will the following YZ cams work ok as I can not get WR426 cams at the moment:

YZ450 03 - 05 intake = 8.9mm lift and 269 deg duration

WR426 01 - 02 intake = 9mm lift and 265 deg duration

YZ450 03 - 05 exhasut = 8.7mm lift and 269 deg duration

WR426 01 - 02 exhaust = 9mm lift and 265 deg duration

So can I replace just the Exhaust Cam to get auto decomp or should I replace both intake and exhaust cams so they match.


You can replace the exhaust cam by itself if all you want is the auto decomp. However, you will realize your best power increase if you replace both cams. Do a search on this and you will find about 3 weeks worth of reading on the subject. Hope this helps.


Thanks Josh, I was just wondering about the lift and duration differences as they are not standard cams.

Looks like both will be the go.

Thanks mate.

No problem, you may want to do some searching to see who has put both cams in an older head. I know that people who installed the exhaust cam only had to set their timing a little different. The marks would not line up properly so they had to count pins in the chain to get it set right. I don't know if this will be the case since you are installing both cams. You may want to PM grayracer513, he may be able to provide more insight on the project with both cams. Hope this helps.


just go for the EX cam.

just go for the EX cam.

That’s what I read too so I only replaced the ex cam on my 02. From what I understand the yz exhaust and wr intake cams complement each other by smoothing out the midrange hit the 01-02 are known for and pull harder on the top end. Here are a couple of links that might help.



Hi All,

It looks like I go just the Exhaust cam as performance is not the priority only the auto decomp. Thanks for the advise and the link to the help files.



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