Any Help Will Be Greatly Appreciated! Thank You! I have an '02 prairie 650 and i live in Florida so practically 0 sea level. A couple of the mods are K&N filter, Dynatek CDI, etc. I recently put the HMF Penland series exhaust on it and rejetted with the Dynojet jet kit. I had the bike running GREAT! (132 front carb : 136 rear carb: 4th Notch with the 2 washers on the "top of the "E" clip: mixture screw 3 1/2 turns out.) Like i said the bike ran great... it then sat for about a month, when i go to ride it again after it sat it would "spit", "sputter", and "pop" right under a quarter throttle. right about "cruising/talking" speed.

I then changed the jets to a 134 front 136 rear with no change, so i put the 132/136 back. i then started messing with the needle. i moved it to the 5th notch but the bike bogged down when accelerated and low end so i moved it back to the 4th notch, however the popping wasn't as bad...

I then cleaned the carbs totally and heard that if you move 1 of the washers to the "bottom" side of the "E" clip it makes it a "4 1/2" (132 front/136 rear) well... after doing so the "Popping" isn't as bad now HOWEVER the "Popping" has moved to just above idle speed, Right around a fast walk/jogging speed but not as "hard" of a "PoP" unless you put the bike in neutral and rev it up then its pretty bad, but still just above idle. Ive messed with the fuel mixture screws from 1 all the way out to 4 turns and still the same issue.

I've cleaned the carbs, tighten the flanges down as tight as they will go to ensure no exhaust leaks and still the bad "Popping/backfire". I've even drained the tank and put fresh fuel in it to make sure there wasn't any water in the fuel. Everything else seems to be fine. Half throttle all the way to wide open seems to be fine, no popping no hesitation, no bogging, nothing.

PLEASE HELP!!! I've been on the phone numerous times with HMF as well as Dynojet with no HELP! ANY INFORMATION WOULD GREATLY BE APPRECIATED! THANK YOU ALL SO MUCH!!!!

 

What you've done to your quad is too difficult/confusing for others to either follow or help...

First this thing is to figure out whether you have too lean or too rich condition by reading fresh plugs or by partially blocking off air intake.