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FriscoKLR

Need some clarification on timing\cam

6 posts in this topic

I realize this topic has been beaten to death but I still need some clarifaiction. I just bought a '00 wr400f.

Am I correct that there are 4 cam\timing combinations:

wr timing\wr exh-cam (stock),

wr timing\yz-exh-cam,

yz timing\wr exh-cam (stock),

yz timing\yz exh-cam.

Or does the YZ cam automatically advance the wr timing to yz spec?

Thanks

Mike

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The YZ cam will have the timing marks in the YZ location. You can time either cam for YZ or WR. What we need to know is what cam do you have?? If you have a YZ cam and you put it in the WR, you want to line up the timing marks just like the manual for YZ timing. (this is assuming that you have cams from the same year bikes) I hope this makes sense. If not, then let us know what cam you have and what timing you would like to use and we can help you even more specifically.

Josh

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It's stock now but I'm going to order a auto decompression exhaust cam in the next couple days. Just trying to figure out if i'm gonna go with a WR or YZ cam and how i'm going to time it. I'm hedging towards the WR cam and YZ timing.

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The YZ exhaust cam has exactly the same lift and profile as the WR cam. The only difference is that the timing mark is stamped 1 tooth advanced from where the WR cam is stamped. No need or advantage to getting a YZ cam. Just retime the WR cam and you will have the same setup as the YZ. The intake cams are identical. The following link will explain it in detail. It's mainly for the WR250 but applies to the 400/426 as well:

http://www.thumperfaq.com/yz_timing.htm

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It's stock now but I'm going to order a auto decompression exhaust cam in the next couple days. Just trying to figure out if i'm gonna go with a WR or YZ cam and how i'm going to time it. I'm hedging towards the WR cam and YZ timing.

No,you can't do that with the automatic decompression cams. You MUST buy the YZ auto decomp cam if you want YZ timing. IF you want WR timing you have to buy the WR auto decomp cam if you want WR cam timing. The pre 2003 bikes were able to be advanced or retarded to get the desired timing be cause they did not have auto decomp. If you try to advance a WR Auto decomp cam to get YZ timing your auto decomp will not work properly because the timing of the decompression pin will be off. I hope this makes sense.

Bottom line, if you want YZ timing with Auto decomp buy the 2003 YZ cam. If you want WR timing with atuo decomp then buy the 2003 WR cam.

Josh

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