| My 1971 Commando has always apparently run very lean. Even when warmed up, she has to be left partially choked. I changed the needle settings and this helped some.
Suddenly it became about impossible to start. I could use starting spray but it would run about 3 sec and then seemed to be starving for fule. I took the carbs apart and the only thing that looked wrong was the needles had some sort of fouling about 1/2 way up - it looked like carbon. I got the fouling off by gently rubbing with steel wool and she runs ok but still needs priming with either starting spray or squirting some gaso into the intake.
I am pretty sure all jets and passages are clear and the float setting is about spec.
The bike has a Boyer ign.