Popping and Backfiring
A:Eric, Start with testing your charging system. Make sure the system is not over charging. That bike probably should not give you a reading above 13 volts dc (depends on weather you are running a 22 or 32 amp system). If that’s o.k. check for an intake leak. While the bike is idling, mist the intake area with brake cleaner. If the idle changes or the bike stalls, you have a leak. You will need to replace the intake clamps and seals.
Discussion
14 Responses to “Popping and Backfiring”
over charging ????
That’s what I thought-if anything maybe coil heating up-Sounded like an intake leak to me right from the get-go.
Also should have done a simple coil test with meter in ohms mode, isolated, as in no plug wires or anything, coil removed from bike-could have saved a few pennies on the new coil.
check your ignition switch sound like a short somewhere if you have fatbob tanks take counsel off and check that everything is tight
I had a similar problem. Anything over 50, bike would pop, backfire and die. Idle was fine, upon a rev in idle fine. But under power and pushing it, it would die. It was a bad fuel petcock and collapsed screen. Check that out.
If it runs good at idle and when you increase revs causing it to bark, sounds like your timing is out, bad coil or fuel issue..Try another coil. Check the carb again.
I’d try a known good coil just to eliminate that as a possibility
You could have a lean air fuel mixture
Replace the air filter, samething happened To me and my friend and it was the air filter in both cases.
Does sound like an intake leak. When checking for an intake leak, use WD-40 instead of brake cleaner (brake cleaner is so volatile that even a tiny bit of stray mist going into the air cleaner will give you a false reading.) Be sure to spray from the right side of the bike onto the seals, again to prevent anything going into the intake. Intake leaks were extremely common with shovelheads…the ignition switch could also be an easy culprit; if it’s not the dash-mounted style it could just be getting worn internally (jiggle the key) or contacting something behind the switch.
Check your coil. I had a simular problem with a 02 fatboy. Changed the coil and problem solved
I agree with all the others, you start at the carb and work your way down but do check the timing and most important check your valve adjustment. If you have a weak valve spring it might not be closing completely at a higher RPM . Good luck. Ride upright.
Could be the timing advance. Check the weights and springs behind the points plate. My 73 had that problem once.
My 2001 super glide does the same thing. Any suggestions?