I have a 72 cl350, and when I attempt to start it, the right side runs fine, but the left will run a very short amount of time, make a popping type sound that sounds like it's coming from the carb, cut out, and then do the whole thing again. Once when it did this, the carb actually kicked back off of the intake boot. I think it's a carb problem, though i've cleaned everything and all the jets and passages seem clear, though I could very well be wrong. Any ideas?
It could be a few things causing the problem. You should first check to see if there is a air leak between the carburetor and the manifold and/or the manifold and the cylinder head.This could cause it to run lean. If they are good the next thing you should check is the ignition timing on that cylinder.If the timing is retarded it can cause the symptoms you described. Also check the float level on that carburetor, if it's low it can cause that cylinder to run lean. I hope this helps. Happy riding.