400ex backfiring & Other Problems

[400exrida06]

I just put a fmf t4 on my quad and didnt jet because the guy at my honda dealer said it wasnt necessary, well i ended up putting the pipe on about 2 weeks ago and it ran perfect, i've been going to the track down my road, i road on the track for the first time yesterday and today and i've been beating on her pretty good but not to much and right before i was getting ready to drive home it started to backfire and when i started it up it would just want to pop, and it sounds like its even backifiring out of the headers, so i dont know whats wrong with it, and another question i had was is there any way to loosen your rear brakes because there always grabbing and i changed them about 3 days ago so they should be wore in by now, but they only make noise when im turning, and when im turning around the burms at the track my front wheels tend to make alot of noise like there, is there any way you can make your clutch looser because mines so tight and hard to pull compared to my friends? thanks alot.

i got the same problem on my 300 i did rejet a couple times but it didn't help im goin to try and go up a few more sizes on the main

[400exrida06]

bump

[duke416ex]

Get a new clutch cable. Second, if you put an exhaust on it will need rejetting. Do a search on jetting, there are some posts that tell you how to check it.

[DeerNuts]

Originally posted by yzfmxer
i got the same problem on my 300 i did rejet a couple times but it didn't help im goin to try and go up a few more sizes on the main

Keep in mind that the main jet only controls part of the fuel delivery. The pilot and needle control the first parts and then the main jet kick in somewhere around 1/2 throttle I think. Im not exactly sure what controls what, but the main certainly doesnt control fuel delivery at 1/4 and lower throttle.