Sporty losing spark

I have a friend who bought an 89 Sportster 1200 not to long ago and after he starts it, it runs for about 5 seconds and then shuts off, It loses spark, Checked it with an inline spark checker. Anybody have any suggestions to what could be causing this? It just started doing this lately, it stranded him the other day, I had him check the connection on the coil and key switch and he said that all looks fine, anyone have any ideas what to check next?

It could be the ignition module under the side cover, especially if it is the stock one. I've seen this happen twice. I changed them out with the Screaming Chicken version and everything was fine. You can check it by swapping it with another one before dropping the money on a new one.

I had one go on my old 1989 Sporty too. It would pop and fart every once in a while at first. Then it would die and then run again after a few minutes. Then it finally died all together before I figured it out. I also changed the coil only to find that wasn't it.

Then it happened to me again on a 1997 Sporty. This time I went straight to the module and bingo.

Good luck.

Yup fixed it right away on a 97 sporty here as well. I put in a screamin' eagle module and it runs alot better now too.