Motorcycle Repair: Ignition coil (1988 Sportster 1200 xlh), accel coils, primary resistance

Question
I was driving this past weekend and the bike died while driving, just like turning off a light switch, no indication or sputtering. After intial checks I relized there was no spark. I did some checks on the bike and I had 12 volts to the coil and the resistance tests on the coil showed the primary resistance was only 1.3 ohms (supose to be 2.5 to 3.1 ohms) and the secondary resistance was in line with the spec. 12.3 (supose to be aprox. 11.5 to 13.5). I also noticed the coil was extremely hot to the touch ( I am just not sure if it was that hot before I did the tests, because I needed the ignition swith on while doing test per the manual). After replacing the coil the bike started fine and I have had no other problems the rest of the weekend. Now this is the second time I have had to replace the ignition coil, the first time was in the spring of 2002 (4 yrs ago) and now I replaced it again using Factory OEM coils. The first time I replaced the coil I was informed that the previous owner used a harley coil, however it was not for my particular model, I think they did it for looks because it had a chrome cover and it mounted in the same place but slightly different mounting configuration( I don't know the exact specs of that coil or how long it was used on the bike prior to replacing it 4 yrs ago but the bike ran fine before it failed). Do you have any idea why I am going through this many coils? If anything in my experiences, a bike or car may need to have a coil replacement once in its life. Any ideas or are these bikes just prone to coil failure, possible due to the constant heat from the motor?

Thanks,
Pete G

Answer
Coils, like everything else on your bike, is man made and will fail at somtime. Its the nature of the beast.
Why your coil failed I dont have any idea. The old one you had might have failed due to the fact it was the wrong one.
The bike is not known for coil failure, but hey due fail. I usually use Accel coils which have a limited lifetime warrenty
Good luck and happy riding
Mike