tuning your Jetting

[preddymoto]

What is the best way to tune jetting. I just got done with my buddys kfx 400. new big bore, pipe, and filter. I know the jetting is gonna be way off. how do i go about tuning that?

[wolffie]

I have NO experience with big bores for jetting, but i for a pipe and filter, read what the companies suggestions are. usually pipes will go up one or two main jet sizes (ex. is 150 to a 155 or a 157.5) and filters go up a half or so (152.5) ALWAYS start out a bit richer, and then back off from there. what is the stock main jet on the KFX (or the current one your friend has) and what is your elevation and current temperature out?

go to the powertrain section or KFX section and post this topic. you might get a couple more specific answers:D