have you checked the valves?

 

idk mine like just backfires when i give it throttle and sometimes it wont idle

 

no havent checked the valves... yea after i got it running i took it up the block ran good for a few min then it started back firing n when i tried giving it gas it would just bog down n back fire.... turned it off when i got back now it wont start

 

u try pull starting it?

 

Try the basics first... Are you getting gas to the carb... Are you getting spark. Its turning over correct?

 

yea im gettting gas getting spark... i also tried giving it a lil gas when i try n start it n it back fires

 

mine is doing same thing but check your timing it should look like this

 

could be timing..backfiring can mean jetting is wrong.. mine was doin the same had spark had fuel just wouldn't start so i dug deeper i broke down the motor and found a WooterWooterWooterWooter ton of carbon build up... i guess the guy before me ran 87 instead of 91... ended up just rebuilding with a 434 Namura big bore

 

mines doing the same thing it wont start it just keeps turning over but wont fire, i checked spark im getting that and timing is fine, idunno what the deal is. Im going to take the top engine head off and clean it all im a novice mechanic as well