I have 1200 XLC (2001). I have not rode much this past summer, but I recently pulled it out to go for a spin. It rode okay, but I did notice it was missing at idle. I parked it and today I went to start it and it was missing really bad. I checked the spark and I am getting no spark or a weak/intermittent spark at the rear cylinder. I changed both plug wires and the problem persists. I checked the spark at the coil and the front is sparking, but the rear is not. Is it unusual for a coil to go bad and only one side sparks? Could the problem be in the ignition module?

I have a HD repair manual for this bike, but it does not cover a single cylinder spark problem. In fact, the test for the coil is whether or not it sparks. Fact is, it is sparking, just one cylinder, though. This Sportser uses a dual spark ignition in that it sparks simultaneously for both cylinder. Any advice to test components would be greatly appreciated.

Here is what I have done so far:

*Checked resistance on primary and secondary coil. They are within normal limits, but on the low side.

* Cleaned and re-gapped plugs (they are fairly new with less than 500 miles on them).

*Checked power to the coil with ignition on. Primary supply is fine.

* Replaced both plug wires.

Any help is greatly appreciated. Thanks.

 

see your other post

 

Have you tried switching the plug wires to see if the problem also transfers to the front cylinder? If so, it's a good bet the coil is bad. You can pick one up at a mc salvage for cheap. Also check compression -the 2 cyl.s should be within 10 lb.s of one another. Hope this helps

 

My 02 injected ultra left me along side the road. The rear cylinder has no spark. I replaced the coil, wires and plugs. The rear cylinder still has no spark. I think I'll start to check the wires back to the control module. Any Ideas?