Measure your crank position sensor (CPS). Last time I measured mine it was ~3.8v RMS, unplugged and at a cranking speed. They have a somewhat high failure rate. Sometimes you can just clean them and that in itselfwill induce a larger pulse.

 

Coils will do odd things. However if you never had spark, then you say you hauled it home and then had spark I would look else where.

 

what exactly do you mean? Are you saying that you wouldn't suspect the coil? I should be suspecting something else besides the coil?

 

Ok, there is most generally a solution to all the problems on this forum and I am no exception. Finally had to take it to the stealer as time to go to Sturgis was running out. They took it for an 18 mile test ride and it crapped out on them.......Yes, there is a God!!! Don't know how they got it back to their shop but they did somehow. They diagnosed it and discovered a faulty ECM. Electronic control module. this piece of stuff energizes the "system relay" which in turn completes the circuit for the coil (ah-ha!!) , fuel pump, and fuel injectors. So, when it was on the blink, little wonder I wasn't getting any spark from the coil........they replaced it (didn't have one in stock between 3 dealerships.....had to order in a week.....but they can stock $5,000,000 in chrome on the walls...know what I mean??? Anyway, they got it in, programed it to my bike, and it seemed to work fine. 3 days later I left for Sturgis and am happy to say I ran 2500 miles with absolutely flawless perfection. Worked like an absolute dream. $550 thankyou very much.........ugh! Guess it costs to play. Anyway, I'm happy now and happy to be able to say it is fixed.

 

Hey steal, my 2003 sportster was having the exact same symptoms over a few weeks time. I took it to the indy yesterday. He seems to think its the coil "going bad". I will post up when I get the official diagnosis.

Did your bike feel like it wasn't running all all cylinders in 4-5 gears? Nothing drastic, just a little chugging feeling????

 

Well... you made a good point to yourself but aren't following it, it doesn't sound like. Don't replace parts ***** nilly. Yes, there are a lot of sources for this problem. First, is yours an FI bike?

The cool spray is a good idea. Or, borrow a coil from a buddy and see if that solves the problem instead of buying one. Could be a short that is confusing your ECM. Could be a bad sensor (cylinder temp... will cause the ECM to shut down the bike but since it stays shut down, it could be the sensor not returning to normal). It could be the Voltage regulator (which is relatively easy to test).

If you spread your fingers around your ignition switch finger grip, does the switch seem hot? If so, that's probably where the issue is. That is what was wrong with mine... and putting in cool fresh gas was making mine run again and I couldn't figure that one out for quite a few stranded events. The gas cooled off the switch. It eventually failed while I was going down the road at 50 mph. Yours isn't acting exactly the same... but you can inspect the connector and put fresh dilectric grease in the connector while you are at it which won't hurt.

HD electrical problems are common, continual on many bikes, and potentially expensive for the guess and replace approach which is, unfortunately, also used by many dealerships because paying them to diagnose is as expensive or more so than paying for the part that is their best guess from experience.

The ECM will cut off the spark if it is receiving any number of signals that tell it not to let the bike run. So will a faulty ignition switch.