Backfire anyone?

Does anyone have a backfire problem backing off the throttle, diving into a corner? I have checked my header gasket, its OK, no blow by, header to exhaust clamp is tight. Whats up with that?

It depends on what you mean by backfire. If it's snapping or popping on decel, your jetting is too lean somewhere. Pay careful attention and see if you get it from high RPM when you back of to 1/2 throttle, 1/4 throttle, and all the way off. Then rejet the circuit for those areas.

If you mean backfiring with loud booms, that's not nearly as common.


If it's a one-time type of pop on decel, I would say that your pilot jetting is spot on. After experimenting with jetting and adjusting the fuel screw, I have personally found that the best throttle response is obtained by having the engine pop slightly on decel. As mentioned above, if it's a very loud backfire, or a series of loud pops, it's a little lean. Try turning out(counterclockwise) your fuel screw about a quarter turn and then test.

Thanks for the replies guys, I'll play around w/the jetting and see if I cant get rid of it.

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