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.

 

any kind of tuner on the bike?

 

if you have a tuner that is the FIRST place to start. remove it and see if the problem goes away.

what about pipes; what pipes do you have?

any diagnostic codes being thrown?

 

If you reverse the plug wires does the problem move to the front Cylinder?

 

i just "***-u-med" that was already done.

swap your plug wires at the plugs. if the problem switches to the frt cylinder then your problem is either the coil or ignition module.

if that doesnt' work, put them back the way they were. now swap the wires at the coil. if the problem goes to the frt cylinder then your problem is either a plug or a wire.

there are a ton of posts on here on how to check the ignition module and coil.

 

I would definatly put a new plug in an give her a go. This has happend to me several times on my XL1200. Although mine is quite a bit older 89'.