quick question on YZ cams

Quick question here folks. What is the difference in cams between the WR400 and the YZ 426. Is it just the timing or are the lift and duration different? Thanks for any replys

although there may be small differences in the cam lobe profiles, the main difference is the way the cam is timed.

The YZ cam timing is a simple procedure, and if you do not want to get the decomp cam, then you can use your WR cam, and do the YZ timing mod this weekend.

If you do not like the extra power (yeah, right :)) the just put it back... costs you nothing except a couple of hours of your time... you probably should be into the motor anyway for a 20000 model, to check valve clearances... another 5 or 10 minutes after you have checked your clearances, and you could be YZ timed and having a blast afterwards...

Good luck,


Thanks for the info. Allready did the YZ timing, nice free mod. I just picked up a new YZ cam and thought the only difference was the timing but just wanted to make sure.

I am familiar with the change on the 400 and 426 models where changing to YZ timing is basically a FREE MOD. I am a little worried with my 450 however, I own a WR450F 2004 and just ordered a YZF exhaust cam shaft, which according to my understandig is required for the model due to the decompression part the 2003, 2004 and 2005 have. Can someone confirm if my understanding is correct? If not I have to cancel my order QUICKLY,..

Thank you

03 cam will not work in a 04/05, the part # you want is a 5UL not the

5TA -12180 this cam will work in the 03/450 and 98 to 02 400/426


The 5UL-12180 is the cam you need they changed the head in 04.

Really? I got the part number from this site http://parts.yamaha-motor.com/

so the info is wrong? Indeed I need a 2004 model. Please doublecheck, because I just ordered the (wrong?) part? If some one responds quickly I still have time to stop the int´l shipment. Thanks! :cry:

I just did the cam mode to my WR426 and the 5UL-12180 would not work in my 01

I had to get the 5TA-12180 for mine.

I just checked there site and the Exhaust cam for the 04 states a different #

however the cam for the WR and YZF are the same # so you need to cancel

that order and adjust your exhaust cam to the YZF timing witch if I remember

right, you advance it one tooth on the chain from stock.

There's a lot of threads on this in here.

I guess the cam they gave me was for a 05.


This is the general rules for changing your timing to a YZ

Thanks Motoman http://motoman393.thumpertalk.com/

Mine is the 2004 WR model. Can some please tell me what PART# I need if any to change to YZ timing? Appreciate it.

I just did mot understand why you need to change the CAM on your 426, I had a 426 and just advanced the exhast cam 1-tooth. As for the models with decompresser, apparently one need sto exchange the cam for a YZ one. Correct...anyone?

I change it to eliminate the decompression lever and that way I can

kick it through with the auto-decompression cam and ti works SWEET

no more 3 kicks for 1 turn over. :cry:

The part numbers are different, you might want to try advancing the

cam like they did on the 400/426's however maybe someone else

has try-ed this and could tell ya if it works.

My mistake they are different numbers for the YZ450F and WR450F

so I would assume that they have different lifts.


from whom are you guys sourcing cams? who's got generally good prices and good service?

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