coils or running rich or???

[nols]

Having an issue with a 1981 honda cm400c. Spark plugs are sooty black. I'm getting a popping in the airbox and backfiring on decel. That usually means running lean but the black sooty plugs is throwing me way off. That usually means running rich.......with power on hitting the start button the power going into the coil was reading 16-22 VDC on the multimeter which is good. I put another plug that I had laying around and tested both sides to the block and they both had spark. If the bike is running and you pull off a wire it dies immediately and wont restart.........Any thoughts on this?

 

[philos1]

check timing and points as well as possibly leaning out your mixture, depending on how old the plugs are, could be gunked up from before....