What's the best thing to do to my 400EX to gain power without spending alot or losing reliability?

 

K&N with Outerwears, Vented Airbox Lid, Header, Muffler, and a rejet.

 

stage 1 hot cam

 

high comp piston w/ hotcam and exhaust and jetkit will really get u movimg if u want to spent a few hundred $ doin the work urself.

 

hot cams, and pistons are good, but they wont do there full benifit without a complete exhaust. so i would say you were just looking for a little power then get a slip on hmf exhaust with a uni intake and rejet it. if you think in the future you will be looking for more power then i suggest you get a complete hmf (or another pipe if you with) exhaust, a K&N intake, maybe an airbox lid mod, and rejet it. that way, in the future you can get a high comp piston and cam and then ur bike will really be flying.

 

im about to upgrade my 400ex with some mods but i have to get some money, so i am going to get stage 1 hotcam, x-4 curtis sparks exhaust, k&n, outerwear, jets and i hope i fly then