popping in the carb?

[shawnsadler]

Hey guys..
we need some help. my brother-in-law just bought a 96 blaster.. it's bored
.040 over and everthing else is stock it just had a rebuild about 3 hours of riding time on it... when its idling it is fine.. when u rev it up it sounds fine but when the revs come down it pops in the carb area. like little firecracker sound. when you ride it full throttle it pulls good it's smooth all the way through the powerband. but off the gas it pops alot... i checked the plug and the main jet seems to be good based off my plug check and i have adjusted the air screw for idle... could the Pilot jet be off? or what could be causing this to pop? i'm not the best with carb settings and all that but i do know a lil about it.. just not sure whats wrong with this one..? thanks for the help..

 

[4cfed]

whats your needle jet?? could be a sever lean/ rich problem when gettin off the throttle

 

[shawnsadler]

found out that one of the nuts wasn't tight on the head and it was blowing out the headgasket on the backside towards the carb... tightened her down and she runs fine now.. thanks for the response though..