What's wrong with this 1200 Sportster?

My dad was riding his Harley down the highway, and it lost fire. He had to pull over and stop. It cooled down for about 10 minutes, and it ran fine for a little while, then did the same thing again. He called someone he knows who said it was either the coil or the ignition. It has no points, and he's not sure of what kind of ignition it has. Which of these (if either) is wrong with it?
I can't get much more info about this, since Dad despises me and Answers. Hopefully this will change his mind about us.

I JUST got down answering an almost identical question....What year is the bike? You will also need to know what ignition is in it, stock or aftermarket

here is what I advised...

Ok...there could be several reasons for this. I am assuming the backfires are through the exhaust???
GENERALLY that is a sign of an electrical issue.
Are you 100% positive you are actually getting spark AND fuel WHEN THIS HAPPENS?....if you have spark AND fuel, it should run, take out one of those and it won't.
How many miles are on the bike?
Has anything been done to it?...pipes, carb, air cleaner, cams, etc....
What is the jetting?...main and pilot.....Stock carb? > DynoJet or Thunderslide kit installed?
Have you checked it for intake leaks or replaced the 3 intake seals lately?

You should either take it to a shop and have them check it out or buy a FACTORY Service Manual for the bike and follow the diagnostic flowcharts.

There are several things that could cause this...
Start with the most simple and obvious....when this happens again, open the gas cap and reinstall it and try to start it...if it starts up right away, the gas cap vent is stuck, get a new cap.

Other possibilities include the coil heating up and failing, and works again when cool.
A faulty ignition module and/or bank angle sensor or cam postion sensor ....these were prone to failure more than anything else....when it doesn't start when hot, will it start again after it cools down after 15 or 20 minutes???...this is a sign of a bad module.(coil also, but rare compared to the module/cam sensor....the CAM SENSOR is what usually fails, but some of the newer 98-2003 Sportsters used a module inside the cam cover with a built in cam sensor and bank angle sensor that were known for failures.)

HD ignition systems are impossible to diagnose without a FACTORY manual, so it would be a WISE idea to invest in one or let a shop check it out.

If the ignition module does actually require replacement...go with a Daytona Twin Tec Ignition SYSTEM, not just a module, the difference in how the bike will run is VERY noticeable. Convert it over to single fire with the module and coil kit.....you will also want the Twin Tec VOES switch and have the timing set to 32 degrees BTDC.
Module Model 1005...... http://www.daytona-twintec.com/model_1005.html

Dad Flying his 40 Sportster

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