400ex jetting with WB e-ser pipe

[bluetaz100]

i just bought a 2002 400ex with a wb complete e-serice pipe system and a k&n filter does anyone know what jets i should be running as the guy that had it before me left in the oem jets and do i need to run without the lid to get enough air in the box any input would be great and thanks tim

[spangman]

My EX seems to be about the same..... I am using the stock headpipe and have no idea what jets are in my machine. It starts like a real piece of crap when it is below 40 deg. but other than that it runs great. sorry I wasn't of much help, I'm sorta lookin for answers myself.

[400ex LB]

I have a 2000 400ex with white bros e series pipe, k&n air filter, and custom aluminum air box w/o lid. I am also having problems with the jetting. I think i need a bigger main jet? Does anyone know what size main jet i need?

[cals400ex]

with the lid on, i would start around a keihin 155 depending on your elevation. this assumes your at normal elevation levels that are not too high. with the lid off, go up 1-2 mainjet sizes.

[JOEX]

A 40 or 42 pilot jet will help with starting if all other components are in good working order i.e. battery and spark plug.