jetting with k&n filter

[s23599e]

i have 400ex '00 with k&n filter

what is the best jet i need????

[400exstud]

When I had just a filter I ran stock jetting.

[BlasterEaten250]

Yeah, stock should be fine.

[s23599e]

oh..... my friend tell me if a put a kn filter, more air= need to rejet

so, with a stock jet 148 it's ok???


and if i remove spark arrestor and put kn filter what is the jet i need???

[400exstud]

Keep the spark arrestor in. It sounds better