more power

1999 400 EX
White brothers pipe, K&N filter, no air cleaner lid, smaller front sprocker, 160 main jet, 38 idle jet and rev limter

Help

[Dave400ex]

Get a JE 416 Piston Kit and a XR400 Cam from Marcum` ATV. Give Marcum`s a call and Terry will tell you everything you need to do the 416 Motor.

You could also call TC Racing Engines and ask Tom about a 416 Piston Kit and a Cam.

[str400ex]

you could also call sparks about a igniton advance key pretty cheap for alot of bang

[MIKE400EX]

Bump that idle/slow jet up to a 40 or 42 also.