96 fxd ev27 cam, stock ignition, high output coil.

 

Check and make sure a lock nut didn't come loose.
That happened to me once.

 

hmmmm! the EXACT same thing just happened to my brothers bike! Dropped an exhaust valve guide! Running down the highway, I was driving his, pulled into a gas station for gas, went to fire it up, running on one cyl! Changed everything like everyone said on here, nothing. Did a compression test, BAMM! pulled the heads off and the exhaust valve guide had dropped down just enough where it wouldn't close!

 

Basics...... Check for fuel, fire, and compression. We know fuel is ok, since one lung is working. Leaves the other 2. A quick compression test will narrow it down. If compression I'd bad, check the pushrods, then start the teardown. If good, it's spark. With a single fire coil, swap plug wires at the coil and see if the miss moves. If not, it's a plug or a wire. If so, it's a coil. The stock single fire module doesn't know which cylinder it's lighting up, so so it won't be that or the pickup.

Did I miss anything?

 

owtlaw pretty much sums it up!

 

I think you mean dual fire where you say single fire but other than that you are correct.

 

Joe, I had that happen to me. Leaky exhaust crossover pipe was at fault, allowing air in to cool the exhaust valve guide. That's my theory anyway.

However, in the OP's case, he was having a miss before stopping. If a compression test is OK, I'm going with ignition. And if it was a pushrod loose, I think it would make a lot of noise.

 

You think you gonna post this without the pic of the good doctor on his knees wearing the doo-rag? I feel gypped.

 

OK, OK, here it is:


And, for the record, a Harley big twin Evo will run 60MPH fully loaded on the front cylinder only with zero compression on the rear.

 

Yep. I do that all the time. I think the terms should be reversed. :-)