I need some advice

[BrianWrightR6]

Ever since I put my white brother full E-Series on my 400 I have noticed it back firing some and not responding to gas well sometimes (allot before it really warms up). I was wandering with just this mod and a K&N filter what jet I should get and what pilot jet? Should I get a 158 main and a 42 pilot or would you recommend any thing bigger?

[BornOnFire]

Dude, if you put on a new filter and pipe, you must re-jet!!! Try a 42 pilot and either a 150 or 152 main. Do that and then tell us how it runs.

[blood red]

what "BORNONFIRE" said