i have a 2002 400ex white bros e series slip on and k&n filter and a k&n filter box lid and i moved the needle clip to #4
on the needle and i am 2 1/2 turns out on the f/a mix screw
165 main jet runs better but still poping @1/4 throttle
am i even close or what first time doing this i am at a lost but it is getting better since the last post
try going up in size on thr pilot jet. exriders.com is a good place to check your jetting , its a honda website.