2002 wr426 jetting

i have a 2002 wr 426, that i am trying to tune. here are the things that i have done so far. i removed throttle stop, removed air box lid, removed baffle in exhaust. bike starts fine and has good low end grunt but on the top it sounds like there is a rev limiter. obviously its running out of fuel and needs re-jetting. all carb jets are stock, and all the settings are stock also.

i live in michigan and will be doing most of my riding in the summer. any info will be greatly appreciated shawn

There is the potential for your throttle to stick wide open with the throttle stop completely removed. You can either use the yz stop or cut the stock one to length following these direction


I have the same bike. You can get a lot of jetting info in the jetting D-base sticky thread. Here is what i am running. Hope this helps!

Model (400 - 426 - 450): 02 WR426

Timing (WR-YZ): YZ with 03 exhaust cam

Main jet: 170

Pilot Jet: 42

Fuel screw (turns out): 1 1/2

Needle model/Clip position: JD blue needle postion #3

Airbox lid (on or off): Lid Off

Pipe: White brothers e-series w/six discs and quiet core insert

Altitude where you ride: So Cal 0-4000 ft

Temperature where you ride: 75-110

Degree of satisfaction: Runs awesome quick response/no bog

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