I just set my timing today and also adjusted the carb. When running at idle it pops, not really back fire just pops and if I dont give it some gas it will quit. Hmmm. Does it sound like its running lean or is it something with the timing? Oh and what way on the air screw is richer, in or out?

 

An easy way to find out, turn the mixture screw, out( richer), 1/2 turn and see if the poping goes away. I would think its lean. Is the idle speed ok?

 

My guess as well. Small popping/backfiring usually indicates a lean mixture.