Motorcycle Repair: harley xl1200 fuel problems., gas line antifreeze, hyper charger

Question
1991 1200 sportster, andrews n8 cams, mikuni 42mm carm krykin hyper charger, single fire ignition and ultima wiring loom.

my bike started stalling this summer, i was in 50C in greece and in spain, i thought it was over heating as it only happened when i was hard on it or stuck in traffic. let it sit for 15 minutes and it was ok again. gradually over the next few months these started happening more and more often. now, i get about 15 minutes and it will stall, just die really no warning just dead. after the first stall now its pretty much game over. i have to let it sit for half an hour now. then it will only go for maybe a minute or 2. i have checked the spark when this happens and i still get great spark. it back fires out the carb and the pipe if i try to start it right away. i changed fuel lines and filter. i even loaded the fuel with gas line antifreeze in case it was the carb iceing up. tryed the additive from harley too. I dont get any error lights on the computer, the timing light is flashing with the spark and the plugs are the right colour, the bike runs perfect untill it dies, and it dies just like you hit the kill switch.  I know its going to be something stupid im over looking.

Answer
It sounds like a heat related issue with the ignition system, but all the checks you've done seem to indicate otherwise. Sometimes the ignition pickup plate will stop working when hot, but if you still have spark at the plugs then this is probably not the culprit.

It might be vapour lock in the fuel line, as the excessive heat from the motor will "boil" the fuel inside the hose and starve the carb. Try routing the fuel line so that it does not sit to close to either of the cylinder heads (you may need to install a longer hose). Also check to make sure the vent in the gas cap is working - next time the bike stalls, open the cap listen for a "whoosh". That means the vent is not letting air in as the fuel level drops, causing a vacuum inside the tank and shutting off fuel to the carb.