Bad Miss on Left Cylinder Any Ideas?

[3Deuces]

1981
New rings
Lapped valves
Rebuilt BS34's w/ 140 mains, 45 pilot, float height, check at 22mm, fuel screw 3 turns out. No holes in diaphragms, stock needles and seats in good shape. New o-rings on seat bodies (Thanks bdholsin!)
Short open pipes w/ lollipops in the end
Uni pods
Pamco and Hughs PMA, B7ES plugs.
Cam chain and valves adjusted. Have not tried to sync or dead cylinder because theres no way she would stay running on only the left.
Timing has not officially been set, but I have tried the center and left and right extremes of the adjustment with no improvement.
I've swapped plugs and coil leads side to side and the miss stays on the left. Carbs triple cleaned. The miss is bad at idle and seems to clear up as RPM increases. Pops out the exhaust and back fires through the carb. Right side sounds good.
Starts 3 kicks cold w/ choke first kick when warm.
Planning to do a compression test tonight just to rule out me F-ing anything up when I did the top end.

Any other ideas?

Thanks in advance

 

[5twins]

If the carbs are 1980 and you have brass floats in them then the floats are set wrong. They should be @ 27mm for the 1980 brass floats. If set to 22mm, they will be way too rich.

 

[3Deuces]

Sorry, bike is an 80, engine and carbs are 81. Plastic floats.

 

[Belle]

Did ya try to set the timing yet?

 

[3Deuces]

No, but I've moved the Pamco plate from the center starting position to the CCW/CW extremes with no change. Right cylinder is running fine. My next step is compression check then set the timing.

 

[uebe]

Might check the left side valves to see if either are sticking

Spray a little carb cleaner around head while running (doubtful but easy headgasket check)

A little carb cleaner around, and in the carbs while running to see if theres any change.