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Temp Correction

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I have a 2002 426 wit hthe lid off and uncorked.

Stock jetting. The bike has lost it's snap when cracking the throttle. I think it's because of the High temperatures and Humidity.

The stock jetting is ..


42 PJ

DRR 4th clip

I was going to reduce the size of the Main jet to a 160 and raise the clip to the 3rd slot. The as found factory setting on the fuel screw was 2 turns out. I was thinking of reducing this to

1 1/2 turns out.

Please tell me if I'm on the right track or do you guys suggest something else?


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Just ignore me, because I always say the same thing, and that is:

Uncorked/uncovered WR is pretty much a stock YZ, so why not try YZ jetting (basically a needle change).

I've jetted three WR 426s, and used E tapers in all of them, all at higher altitudes too, and all ran much better than with the stock D.

Granted, that was the only D needle I tried, but IMO once you rid the WR of all that silliness you should just jet it like a YZ.

In my experience the cam timing (which I tried on one WR) has no effect on the jetting.

Disabling the air cut valve does seem to clear up what can be a little weirdness at lower throttle and idle also, but any serious bog is going to be on your pilot and needle IMO...

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