backfire after hmf install

[tnc110]

just installed a new hmf full system on a predator 500. it backfires...blue flame, with loud popping. tried adjusting air/fuel screw and needle with no change. I plugged exhaust tip while running and it never died...i guess i have a leak. not too impressed with the hmf header install. how do i seal this thing up better. nuts are as tight as they can go....

[Scro]

You will need to rejet the carb if you haven't already. The header gasket should also have been replaced when replacing the header.

[tnc110]

i installed a dynojet kit...im on the 3rd groove w the needle, 3 turns out on a/f screw, 180 mj. I havent tried messing with the main jet. before i put on the hmf i was running the stocker with the spark arrester removed and several holes drilled through the baffle. It ran like crap until i went all the way up to a 175 mj. i ran the 180 just to be safe. do you think i need go up or down on the mj with the hmf system. i didnt know an improper mj would make it backfire? also i have a uni clamp on filter...no box.

[Scro]

You will also need to go up on your pilot jet. This is probably causing the backfiring issues.

[tnc110]

i was afraid of that...why the heck does dynojet not include a larger pilot jet???

[fmftrx300ex]

because there for inexperianced ppl who they dont expect to be making huge changes to intake set ups or exhaust and think about it itd cost them more to include them and theird be alot more confusionfor people who have no clue wht to do