450 cam swap for 2002 wr

After reading all the positive feedback about the cam swap. I came to the conclusion that I need this auto decomp on my 2002 wr 426.

I'm not getting any younger and I feel the bike is plenty powerful as it is. But to have an easier starting beast would be really nice. Before I proceed I have a few questions :

From what I read, to get the most effect of the decomp feature I have to go to the YZ timing. If I keep the WR timing, the decomp effect will be lessen, right ?

Does the WR 450 exhaust cam have the decomp feature ?

Can it fit in a WR 426 2002 ?

Also from my location (near Montreal Canada), where can I get the parts I need ?

Did any canadian from the east performed the mod ? Where did you get your parts and how many $$$cdn ?

And if it's really to difficult to get it here, what is the best place to order it on the net ? At what cost ?

Thanks and bests wishes

I don't know about all your other questions, but I just ordered my YZ450F Exhaust Cam from www.worldofcycles.com. Call them with the part number (5TA-12180-00-00), and complain when they tell you it is $143, and they drop the price to $87 US... Best deal I found...

this will fit a 02yz426 too?

if so maybe we could get some bulk discount here? i don't mind paying you via paypal if you'll send it on to me in the uk? I've been chasing this thread through the yz froums and come to the conclusion that I too am too old to be kicking a 426!

I belive you also need to de-comp bungs too. I was quoted these two part numbers:




the wr is also auto decomp. if you think you want a wr cam you might want to go to the for sale thread and post a "want to buy". a couple members have put yz cams in their wr's and might be happy to cover some of the expense. they should also be able to fill you in on any problems with the install.

superb, will do, thanks

Pertaining to the purchase of the 450 cams...

If anyone in the Denver/Colorado Springs area is interested in this mod, Doug from Excel Yamaha Motorsports on Colfax 303-274-0203 will match the price for the '03 YZ450 cam at $89. When he picked the phone up, he said they go for $140, but like Galants post above, when I said that world of cycles is selling for $89, he said he'd match it (you should mention you heard this rumor on Thumpertalk though) Nice 'cause he's local too - no shipping!! :D

Also, I just called Hotcams to see about their 426 cam. They FINALLY have the 426 cam with the autodecompressor in stock and are selling at $159. I got lucky and talked to the R&D engineer Clyde who works there. He described the 426 cam with the decompressor as basically a stock cam with stock characteristics but with the addition of the autodecompression. No powerband shifting gains to be had from it. And dont be thinking you wont have to shim it, he said that it was ground from the 450 cam body, so the same shimming will be required similar to the stock YZ450 cam modification. (it initially sounded like a simple remove and replace operation, but he said that since they didnt expect to sell that many, they just used their 450 cam body and put the 426 sprocket on it, which means the cam will have to be shimmed).

BUT- He did say that the new 450 cam he personally designed is totally revamped and it takes some of the low end torque and (since the 450 has plenty of low end) and puts it on the top end. He said the power now will be much "smoother" than the stock YZ450 (not so explosive) and much better than the stock WR450. He said the "new 450 cam is a huge improvement over stock" and pulls away from everything in the higher RPM range over stock.

SOOOO, this may be a good mod for me and my WR. I was going to order the stock YZ450 cam as per the PDF file I've seen in this thread, but with this 450 HotCam, I may get this one instead and end up with the decompressor along with some performance gains as well. I cancelled my stock YZ450 order through Doug at Excel in Denver. For roughly $70 more, I may order the 450 Hotcam and get some performance in addition to the easy starting.

If anyone has anything to add to this...by all means. But from my research, it appears the the new 450 hotcam is the way to go for my WR426. Does anyone have any experience with this cam in their YZ/WR 450??? :)


I put a "CW" modified 450 cam in my WR426. He took a yz450 cam and installed a 426 gear, set timing between WR and YZ. It has a lot more midrange than stock WR had, maybe a tad less right off idle, then about same low end, and a little more on top. Middle range is way more, 5th gear wheelies are easy.

By "CW" do you mean the CW here in the Thumpertalk forum? If it is someone different, can you provide their contact info?

Would you say you like your WR better now?

How much did this mod set you back?

Did you still have to shim?

By "CW" do you mean the CW here in the Thumpertalk forum? If it is someone different, can you provide their contact info?

Would you say you like your WR better now?

How much did this mod set you back?

Did you still have to shim?

Yes CW the TT member. He has a lot of post on the YZ450 cam thread. I like the extra power except in really tight rough trails it won't pull as smooth right above idle. But this bike is not meant to ride that slow anyway, I am use to riding my XR400. From about 2K rpm and up it is much better.

I think CW gets $240 for this becuase he has to buy a 450 and a 250 cam to get all the parts. Now that Hot Cams has one, that may be a better option.

Yes I had to change shims, but thats no big deal. It's routine maintenance to adjust the valves anyway. Go to the YZ450 thread and see "Cam mod please read". It has over 500 posts on this subject.


I'm wondering what the difference would be in power if I went with the stock YZ450 cam vs. the CW cam you mentioned. I've talked with Curt and he REALLY seems to know what he's doing (he should be working for Hotcams!). But since I can get a YZ450 cam for around $90, so if the powerband between both cams is similar, then the only benefit to the CW cam is that he puts the actual sprocket made for the cam chain in my bike (which is what I prefer). However, I havent heard of a failure yet (or excess engine noise) due to the stock YZ450 cam in the WR426. If thats the true case, then I could get away with spending $90 instead of the $250 he quoted me.

As to my style of riding, I'm an enduro kind 'o guy and like trails and single track. I'll next to never run the MX tracks except when everything else is snowed in.

What do you recommend: stock YZ450 or Curts cam???



after reading the thesis ;-) on the yz450 implant I've decided to buy a genuine 03 yz450 cam for my 02 yz426. It cost around $103 inc UK delivery for the cam, bung and s&H, from generationmx

There's a guy who emailed me with anote he's machining a good fitting bung, rather than the 03 which has to be squeezed in - I think he wanted $5 inc post for one.

I've ordered mine you I'll post when it arrives and has been fitted.

Give us a ring at BIKEPREP in WALES 01269 832255 and we will sort you out a good deal on the conversion.We specialise in breaking yam fourstroke bikes.

www.bikeprepmx.co.uk bikeprep@yahoo.co.uk :cheers:Roger

Just ordered my auto decomp cam from hotcams today, just went in the catalog :)

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