Why Does My Harley Backfire?

harley exhaust
Robert asked:

My Harley Davidson starts and idles great, but as soon as I give it any throttle to speak of it will spew fire and pop from the exhaust.

It sounds terrible, is very embarassing and I am wondering if it is hurting the engine.

Thanks in advance for any help you can give.

Our Answer

Robert....it's very difficult to answer a question like that without seeing the motorcycle or being able to observe it.  I would have to guess that you are probably experiencing a rich condition to some degree.  Depending on the bike you may need more accelerator pump or you may need some work on the PCM. Too many variables.

I'd like to help but given the information, it's hard to say.  We would need to know whether it's been modified in any way...did you install cams in it?  Any engine work done recently?  How does it run the rest of the time under load?  Etc.