i just got it (dirt cheap)so i don't know much about it but it backfires out the carb at an idle and low rpms i noticed the the carb boot was split so i replaced it and it still does it. I also checked cam timing its ok, checked intake valve it had about .006 clearance at TDC.

 

.006 mm or inches? also, did you check the exhaust side?

 

check for loose plug...bad accel pump...(if the rod is even in it)..the one i just bought was missing..lol

or jet blockage

if it has a aftermarket adjustable exhause...take some discs out...to create more backpressure

 

how dirt cheap was it?

 

should have around .003" intake and .005" exhaust.
Poping or backfiring out of the carb is a lean condtion.. pilot circuit or fuel screw on the bottom of the carb is pluged or has to be adjusted.

 

MAKE SURE THE BATTERY IS FULLY CHARGED TOO....

 

It turned out to be the pilot screw i turned it all the way in and the back out 2 complete turns and it runs great. Thanks alot for your help.

 

money! sweeet.