FMF Powerbomb and PowerCore 4

[nky400]

I am about to get the FMF Powerbomb and PowerCore 4 exhaust system for my 2002 400EX. What kind of power gains can I expect? Will I have to rejet the carb or not? I have heard that I may not have to. Thanks for any feedback.

[[_4ex_]]

u would have to rejet ur carb

just buy a k&n jet kit or dyno jet kit and did some plug test

I've ran that exact setup and I ran a 150 main with the airbox lid on..40 or 42 pilot jet and the needle clip on the 4th notch from the bottom..that should get ya just about perfect on jetting..

YOU will have to rejet..don't think you won't..

[RuffRyder400ex]

A friend of mine has just the power core and it gives pretty good low end power but it is loud too.

[*FoX*KiD*]

i have one on my 02 400

i put a dyno stage 2 jet kit with the full system and i gained hella low end and mid range not to much top end but the low end is sweet for hills

and its not too loud too

[JD400exrider]

Go to FMF web site. That gives the Dyno chart on the set up. Also the recomdned jetting www.fmfracing.com


;)

Set it up like I mentioned and you'll be OK..we have the same elevation so it should be perfect.. But get a dynojet kit so you can experiment with the airlid on..off..holes in it,,whatever ya want.. Don't half arse it and buy 1 more main jet and makeit work..

[nky400]

Thanks for all of you help. If anyone has anything else to add, please do. I will let you know when I get the exhaust on. It should be in on Wednesday. The quad will be in the shop a couple of days getting the valves adjusted, so the exhaust won't actually be on until next week. Rico - thanks for PMing me back so quickly.