jetting 01 yz426 for white bros. E-2 exhaust?

I bought a White Bros. E-2 exhaust for my 01 yz 426 thinking it would lean it out a bit because it always seemed to run just a bit rich with the stock silencer where I ride at home (800-1500 ft. elev.) The bike ran best over at the coast on the dunes at sea level. I have a K&N filter on it and thought that the W.B. exhaust would help it breath better and lean it out. It has more power on the top end now but it seems like in the low and midrange that it lags and doesnt want to accelerate well. It seems like its running rich still. Does anyone have any jetting tips or suggestions for me. I asked the local bike shop and they said the stock jetting would be fine with this White Bros exhaust.


it richer now than it was.

you have 100% stock jetting currently?

Yes the jetting is 100 % stock right now and it seems like it is running rich now because it seems like it has to clean out to get up to the power on the top end. Wierd huh?

lean the main jet a few sizes and retest.

Thanks Eddie,

Ill give that a try.

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