My panhead backfires through the carb while cruising. It accelerates very well and rund well with the throttle closed. It idles great. At 50-65 mph at a steady speed it will backfire through the carb intermittantly so I either accelerate or decellerate.
I pulled the plugs and they are tan so I think the carb mixture is fine.

I just bought the bike from a widdow so can't ask the owner any questions.


What can be wrong??

I would suspect timing.

Thanks! Do you think the timing is advanced too far? Like I said, the bike accellerates very well. I talked to an old HD owner today at work who told me that it could be a leak between the head and the intake. I tried spraying WD40 around the intake clamps but didn't notice a difference in engine idle or exhaust.
I'll look at the timing this weekend.

If its mechanical advance, see all moves freely.