Intake Cam Part Numbers '03 & '02 YZ vs. WR?

Does anyone know if the intake cams are the same for '02 and '03 YZ (same part numbers)?

How about the WR intake vs. YZ in '03? Are the numbers out yet?

The reason I ask is Yamaha claims improved valve timing for the WR in '03, and I wonder if they changed both cams or just the intake?

Also, has anybody got the '03 WR cam in their bike yet?





Don't know.


Hope that answers your questions.



Bardwell Yamaha can't get access to the fiche yet, so I don't think anyone else will know the part numbers for the WRs. I'm wondering about the same things as you though...

Have you ridden your bike with the 03 cam with the YZ timing yet? What is the difference between the way you have it (WR retarded timing) and the 03 YZ timing? Do you lose noticeable low-end with YZ timing, gain mid-high-end instead, stall more with YZ timing, etc.? I know you've posted that the compression is more with the WR timing AFA starting is concerned...

I tried changing to YZ timing but it couldn’t start. May have done it wrong but I doubt it.


I haven't tried YZ timing yet. I probably will. Thanks for the info about Bardwell.


I thought that could happen. My theory is that when you retard the cam (which is what you do in the WR - YZ switch), the decompression bump will be retarded too. This "breaks" compression later, allowing less compression buildup for actual combustion.

The YZ-WR switch advances the cam, for more compression before combustion (closer to no bump at all).

Then again, you might have just done it wrong. I'd be interested if anyone else tries it and gets the same result.


Toby - when you've tried the YZ timing, please let us know the difference.

If YamaFreek has done the timing correctly then what this tells us is the 03 YZF e-cam can be used for both timing but the 03 WRF e-cam can only be used with WR timing. Good to know! :D I think I will stay with the 03 YZF e-cam order just for this ability incase I don't like one timing I can go to the other :D When is that freakin' thing coming in? :D :D

YamaFreek, you may have to get in line too... :)

But first lets see what the difference is, hurry up and try the different timing Toby! :D :D

I think someone else who have switched from WR to YZ timing via the 03 e-cam swap stated that they lost some low-end but gained mid-upper end snap and he hasn't decided which timing he likes better yet. I've never tried the YZ timing yet, but I'm curious as to the difference since I will be putting in the 03 e-cam soon. I like the low-end more since I live mostly there so I don't want to lose it if it's too drastic of a change. Hmmm, decisions, decisions... :D

I tried changing to YZ timing but it couldn’t start. May have done it wrong but I doubt it.

Did you double check all your connections? Spark plug hooked up?

With electric start, you should at least get some combustion.

I think the problem is (as Toby eluded to it), is that with the WR e-cam set for YZ timing, the decomp lobe is in the wrong place hence there might not be any compression and therefore the engine won't start - correct me if I'm wrong Toby...

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