08yz with wr cam?

3 replies to this topic
  • gdbarr1976

Posted June 09, 2008 - 06:51 PM


Got a 08 yz450f that I run in hare scramble. I have heard that a wr cam makes it nice in the woods as in less stalling. I rode a 07 wr450 in a 24 hr race this past weekend and not one stall. Very nice. Anyone tried this? Can I reset the timing only? Do I have to get a new cam and which cam, intact or exhaust?


  • grayracer513

Posted June 09, 2008 - 08:51 PM


Both cams in the '07 WR are different, for one thing, and the exhaust cams cannot be retimed without also modifying the auto decompression unit.

The smoother performance at low speeds is a function mostly of X things:

> A much heavier flywheel

> A significantly lower first gear

> An entirely different ignition map

> and then, milder cam timing

Changing the cams alone won't do it for you.

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  • gdbarr1976

Posted June 10, 2008 - 03:54 AM


Thanks Grey racer. I've got a heavy flywheel and a rekluse and it is great but I will still stall about once per race. My jetting is good and I have just learned to live with it. Perfection, it's never easy.


  • grayracer513

Posted June 10, 2008 - 06:23 AM


If it stalls with that combination, something is wrong. If it stalls on a throttle chop, it may be because the idle is too rich, which is common because people have the idea that any decel popping must be an indication that the idle is lean, when in fact it isn't.

The release rpm of the clutch and/or the idle speed may be set a little too low, also. Seems like something you could fix.

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