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txthumper

426 cam timing

9 posts in this topic

i picked up a 01 yz426 today, went to check the valves, and found 14 pins between cams, aint it supposed to be 12?

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well i did a search, and i keep coming up with 12 pins for yz timing and 13 for wr timing, it has stock cams in it, 2001 yz426...now i dont know whats right, 12 or 14

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well I know that its 14 if you do the 450 cam mod. I looked in the service manual and couldn't find anything other than the marks on the cam. If you look straight on from the gears you should have both the marks on the cam lined up with the surface of the cylinder head. Check that and let us know.

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If you are using the original, manual decompression, 426 cams, the first thing to do is stop counting pins between cams. That isn't how it's done.

The sprockets will each have three punch marks labeled with an I, an E, and another with no label in between them. Use the I mark for the intake, the E mark for the exhaust , and forget about the number of pins between the two cams unless you are trying to re-time a YZ as a WR, a WR as a YZ, or using a YZ450 cam to add auto decompression.

Need a Manual?

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ok, thanks Greyracer, it will be a few days before i get it back together, had to order parts

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for 400 and 426 only with stock cams

That is a rather late reply, but better late than never.

Using stock cams, you have at least 3 options of timing.

12, 13 and 14 pins between upper punch marks on the cams, but make sure that the rotor is always lined up correctly.

13 is by all means WR timing and it will line up left punch mark on the exhaust cam and right punch mark on the inlet cam with the head surface.

12 and 14 will only line up inlet cam's right punch mark with head surface, exhaust cam will be tillted back or forth, considering which setup you choose.

I to used 14 pins between marks and can say that bike starts and runs normally, but I messed up when putting together...14 pins was not my wish to use.

Went back to 13 and in comparison, have more bottom and the same mid and up power, so 14 is workable but doesnt do anything better in power curve.

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