I JSUT RACED THE 04' 400EX WITH THE BIGGER 38MM CARB IN IT AND JET KITAND K & N FILTER AND WE WAS PRETTY MUCH DEAD EVEN AND MY KFX 400 IS 100% STOCK! WHAT SHOULD I DO TO MY KFX TO SMOKE PAST THIS 400EX WITH OUT GOING OVER BOARD IN MONEY?

 

Well if you have enough $$$, get and aftermarket pipe (don't ask just pick one!), or there are numerous other little things you can do like buying a K&N filter, taking off the airbox lid, and rejetting. This will give you much needed low end power.

 

I dont believe it. My KFX with a pro ciruit pipe, k&N and rejetted can keep up with my 12:1 440EX. KFX and Z-400's make the hondas look like trash.

 

The 38mm carb will make a big difference, but I don't even think they're on showroom floors yet.

 

Cheepest way 13T front sprocket.

 

smaller front sprocket will make you loose top end.
Take the airbox lid off and put a bigger mainjet in it. you will notice a power gain.