since i got my pipe a month ago, it has backfired three times. not when decelerating or anything else, but the second i hit the start button. it runs smootly all other times. when i hit the start button, "bang", it sounds like a gun shot. then next time ill hit it and itll be perfectly fine, start right up and run fine or a week or two and then it randomly happens again. whats up with this. is it at all normal? could it be the idle curcuit? i know backfiring when decelarating means its leans but i dont have that problem at all. it rides smooth as silk. thanks for any replies/warrior86

 

Warrior86, what size pilots are you running and what filter setup? Slim

 

Here's my BIG BANG theory: When I first brought home the new shinny quad home my son would sit on it and pretend to be riding it and pushing the throttle while the quad was off and later on when I would start it BANG same thing your talking about, now test my theory and see if it the same thing with yours, after you get a good start without back firing shut it off and press the throttle a few times wide open and then try and start it if you get your bang there's your problem!

O.K. I lied it wasn't my son it waaaaas me!

 

did u rejet your carb when u put the pipe on? if not thats wats wrong

 

mine did it once, it was really funny though cuz my dog was running up behind, then BANG, she wasnt around anymore lmao

 

You might try rejetting the carb up a size or check the adjustments on your valves.

 

well i check it tomorow when my raptor is available. now that i think about it, you may be right about the hitting the throtle thing. cause the first time it happened my girlfriend and her friend was sitting on it and messing with it so i woulld be surprised if they hit the throttle a couple of times. as far as the jetting goes, i took it to my local shop when i put the pipe on, i think they said they moved the clip and adjusted teh float or something. Whatever they did worked cause i have great throttle response. if anything its a little rich when i look at teh porcelain but i havent been able to do a main jet test and look at the electrode. air box is all stock with lid on...no holes and stock filter cleaned regularly. thanks for the replies, warrior86

 

Your intake valves are probably too tight. Mine was doing this and I checked they are waaaayyyyy too tight! Do this and see what happens.

Street

 

Mine did that when it was stock. It was a few weeks old and it did it. Now i have it piped and jetted with a k&n pro-flow. It has done it a time or two with the mods so i dont think it is anything to worry about. But i could be wrong.

 

Trust me, it is the intake valves.[img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img]