Is this jetting necessary?

I've got a WR426 that I run on the road only as a supermoto. I've been using it with a DR K pipe on it, and a gearing of 15/40. It's throttle response is awesome as is it's overall power delivery.

Are people re-jetting their bikes because some pipes necessitate the need to do so, or are you just firkling with the bikes cause you enjoy it?


Pull your plug and see if runs lean, does it backfire on decelleration? You can possibly find more power, if your willing to tweak your jetting.



97 KDX220, 86 TTR225, 99 WR400f, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. De-octopussed. Works frame guards and Thumper Rad Guards, Scotts steering damper. Odometer and headlight removed. Moose hand and mud guards. YZ stock tank, IMS seat and number plate. Renthal Jimmy Button "highs" and Renthal Soft half waffle grips. AMA, SETRA, Happy Ramblers MXC.

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