My 1985 flht developed a miss last year. It did not happen often but you could be going down the road running great and alll of the sudden it would start losing power the tach would be jumping and it would start backfiring. You could let off the throttle and it would smooth out and when you would throttle back up it would start again. After a couple of miles it would smooth out and run smooth. The old bike has 125000 miles on it so I rebuilt the engine this winter. After running it a couple of days it has started being contrary again. I have checked for intake leaks, checked the coil and ignition and I am stumped. Any help would be greatly appreciated because I have a 3000 mile trip coming up soon.

Thanks
Chris

 

try changing the ignition circuit breaker that's under the speedo. there are 3 under there. i just changed all 3 on my 85. i think they are 15 amp. i ordered them from a napa auto parts store. i changed every ignition component on the 85 and nothing helped. the only thing left was the circuit breaker. that was the problem.

 

It's not common, but I have seen a bad tach on cause them to do that. But in all fairness, sounds more like a bad/corroded connection somewhere. Kill switches can get funky with corrosion and cause that too.

 

Might be as simple as needing a new battery.

 

Thanks for the help! I relpaced the circuit breakers last night, went for a short ride and did not have any issues. I will put it to the test this weekend.

Thanks again
Chris

 

Also, the wire between the pickup in the cone and the frame will break inside the insulation. You won't be able to see it. The wire is tied to the frame and the motor moves, so the constant flexing of the wire eventually breaks it. That will give you an intermittant ignition like you describe. I fought that one for years before it finally died completely and I could trace it down.