DIRT BIKE mag. auto cam

i read the whole lengthy post on the yz side bout the problems of putting a 450 cam into a 426, and the altering needed to even dream of it working, but just got my latest issue of dirt bike last night (off-road cr250 on cover) and it say in the focus on four-strokes page that "good news, the new 450 cam with auto decompression drops right into existing 400/426s"...


the 426 has slightly different cam characteristics than the 400s, doesn't it, and dirt bike is saying that it drops right in like a bolt on mod, no problem???

anyone else have an opinion. i think that dirt bike needs to send a rep over to hang out around thumpertalk before they go posting anymore "focus on fourstrokes" advice. :)


NO. The head on the new YZ/WR is smaller, the cams are lighter, and the valve angle is different as well. I seriously doubt that the new cams would fit the old head.

There are alot of guys running the 450 cam in their 426's!!!!!!!!!!!!!!!!!!

No problems yet have been posted! Spoke with Racers Edge and they put one in a while ago with no problems!

I am running 450 decomp cam in my 02 wr426f and has more low end torque and power is awsome! On yz side forum alot of people have made the change with no problems reported

well, I know I have over 800Kim's on my 03 cam... no problems... YamaBen and I wrote the PDF instruction sheet...

Plenty of positive reports about it... there are changes to the head, no one doubts that... but they do not affect the cam as such... there is a small issue, but if you read the post over on the YZ4xx forum, you will see that it seems to make no difference...

It is basically a bolt-n-burn mod... very little to do except to add slightly larger shims to compensate... while you are in there, check the inlet valve clearances, but otherwise, there is no major alterations needed...


Stop trying to convince em David, he who beleives will benifit, he who doesn't will suffer :):D

so what you're saying is that my bro could buy an 03 cam, and just drop it into his 98 yz400 no problem as long as you shim it to spec???(i have no problem starting my wr400, so this isn't an issue for me, but my bro could benefit from it) no cam gear problems, chain length differences, etc??? i read as much as i could stand on the yz4xx forum post about this topic, and sounded like people were modifying their cam sprockets to be itdentical to 426's.

??? if this is jsut a bolt up mod, how much is it? i heard $140 for cam, that correct???


racer36 :)

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