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twin cam efi occasional backfire

I have to admit 1 thing. You are a man of Patience. Wow, I figured you fixed it & never posted what you found.

So you have NO other issues with the bike except this miss/backfire at cruise. Engine Starts OK,, Idles OK,, Roll on throttle-heavy load is OK,,, No other issues?

If it was a secondary voltage breakdown, I would think a "roll on" heavy load acceleration would also show something. If it was crank sensor I would think maybe some starting problems when crank sensor output voltage was low due to slow cranking speeds...

That kill switch, as mentioned earlier, sure would do it.

Is it something that you can almost predict will happen when you go out for a ride or does it only happen once in 3 runs?
 
I have a similar problem. Engine will very occasionally misfire. Anyway, this is a 2005 Road King (EFI). Bike has about 10,000 miles on it now. It has a stage one download, stage one air cleaner and Samson Rolled Thunder oval exhaust. Other than that - no other mods.

I'm calling this a "misfire", not a backfire because the engine absolutely stumbles, hesitates, loses power for about 1 second at the same time I hear the pop type noise. The noise almost sounds like a muffled backfire through a flame arrester/air cleaner rather than an exhaust bang.

The misfiring appears to have started when I ran the bike out of fuel (on a very long stretch of road with no service stations)...

The misfire seems to happen ONE time only, each time the motor is run. Sometimes within the 1st minute or two of riding, and sometimes not for 10-20 minutes. It seems really strange to me to have that type of randomness and one time occurance.

I just changed the battery, which I know was low - but that did not help. I am planning to replace the spark plugs (reasonably inexpensive solution) to see if that helps.

Any other ideas?
 
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