Popping and backfire from left exhaust

[tom1104]

Hello all,
My CB77 runs and rides well with good compression, timing is all good and the bike starts up nice and easily. But I have a constant popping from the left exhaust, I’m guessing it’s probably unburnt fuel entering the exhaust but I can’t seem to solve the problem. Any ideas? Both carbs needles are exactly the same height (checked with the bowl off) cleaned the carb out a couple of times. The popping is consistent every couple of seconds.

[deuce_7]

Could outside air be entering into the exhaust stream? It can cause banging exhaust. You might check all exhaust joints, clamps and seams.

[tom1104]

Thanks for the reply, I noticed when looking at the parts for the exhaust on the cmsnl there’s two types of gasket for the muffler, one circular Red and the other larger black gasket that slots into the muffler. Do these make any difference? My bike also hasn’t got the stock split collar for tightening down the header, instead a full circular piece which I think is a bit longer than original.

[deuce_7]

Go with the stock and tried & true split collar, I would think. Not familiar with the one piece collar. The split collar is suited to conform with header contours / curves and is what Honda used successfully

Not familiar with the different muffler gaskets. Others may be. But, start at the header-to cylinder joint first and work back to muffler.