valve timing

[keithm]

it occured to me that the steady popping at idle and the inability to take throttle without backfiring thru the carb, could be a "jumped" timing chain

 

[Elmo]

it occured to me that the steady popping at idle and the inability to take throttle without backfiring thru the carb, could be a "jumped" timing chain

Or a stuck intake valve or one that is adjusted too tight.