My brother has a 2002 400 EX and he just put a 440 Wiseco Big Bore kit, a Big Gun Pipe, and a K&N air filter in it. He is wondering how to jet it to get the best performance out of it. Any help is appreciated and any other mod help is welcomed.
Thanks in advance.
Dan

 

what temperature do you ride in? whats your elevation? what compression is the piston? did he put a cam in?

 

Ridden in Michigan, I don't know elevation temps range from 40 to 90. I'm not sure of compression ratio but will check. Stock cam. Thanks