backfire at idle????WHY???

[iwannagofast]

So I'm on the way to work this morning and I get to the first stoplight and my bike starts to backfire, then continues to do it only at idle the whole way to work every time I stop, no big deal just thought it was being stupid because it was cooler, at lunchtime and a when I got off today at 6 this afternoon the same thing happened. I ride about 15 miles to work one way and it was well above 90* at lunch and on the way home. Whats the deal?

P.S. I think its only from the left cylinder.

 

[iwannagofast]

prob should have put this in 1975 cb360

 

[SrgtBear]

Back fire can be a result of a poor gasket or hole in one of your exhaust headers or muffler. It's usually a result of air getting back in the pipe from a different source. Might need a new gasket between the header and engine port or between the exhaust and tail end of the header.

 

[djelliott]

Could be a bad carb insulator or insulator gasket. let the bike idle and spray them with some starting fluid. If the idle picks up then thats the culprit.

 

[iwannagofast]

This afternoon I tried spraying the carbs down and nothing happened, I also checked the exhaust gaskets and pipes for leaks and found nothing there.

A guy at work used to put these things together and fix them when he worked at a dealer, he said it could be running lean and that I need to adjust a screw on the carb, but I have no idea which screw. Anyone know?

 

[hillsy]

This afternoon I tried spraying the carbs down and nothing happened, I also checked the exhaust gaskets and pipes for leaks and found nothing there.

A guy at work used to put these things together and fix them when he worked at a dealer, he said it could be running lean and that I need to adjust a screw on the carb, but I have no idea which screw. Anyone know?

It would be the idle fuel circuit screw. But more than likely the carbs need cleaning before you go adjusting anything.