Motorcycle Repair: Shutting Down, ohm meter, electronic ignition

Question
I have a 1980 FX 1100cc (1200.00 miles) sportster w/ glass packs. The bike has not been run in a year, it starts right up, but when the bike gets warmed up and you take it for a ride after 3rd gear it will back fire and shut off, leaving me stranded. Help.   Thank You,  

Answer
You either have a bad coil that is breaking down when it gets hot or the carb is plugged. Test the coil after it shuts down or put it in a oven for a while at 150 to 200 degrees and then test. If you need to know how to testlet me know. You will need an OHM meter.
You never said if you had points or electronic ingition, but the electronic ignition can break down under heat.
Let me know what you find
Good luck and happy riding
Mike