gotta go faster

[Reggie44]

Hey,, I'm still wanting to beef up my 400ex a little bit. Right now I have a K&N filter, White bros e-series pipe, and a 152 main jet. I was wondering about a CDI box or rev box, and maybe and advance key ignition. Does anyone have any idea's as to how much that would help. Or any suggestion they might bring to the table. What about changing the pilot jet, does that help much.

[81 clark racing]

id get a head pipe. and yes the rev box will increase ur rev limit buy 800-1000 rpms dependin on what kind you get. i have a brand new dynatek ill sell for 80 ahipped i paid 94.99 but then i found out u cant run a timein key with a rev box. 2 much adv timeing and could cause pre denation (sp) soo but ya let me no if your interestead pm me

[400flava]

how much are u looking to spend and are u mechanicle inclined? you could get your head boored to a larger displacment for 60-80 dollers and then new high compression piston My11:1 wiseco 2mm oversised was 200cdn (you can run up to an 11:1 on pump gas) instead of your stock 9.1:1 you could also do a cam. it is recomend that you change your valvue springs when you do this if it has been a while not sure exactly how many hours on it sorry. Look into getting a complete pipe also will help as said above ^. Cheaper ways to feel more power drop a toth on the front sprocket rev box wont help to much as a 400ex produces its max power before hitting the rev limiter but will add a little.
Hope it helps