Problem with 1980 showerhead is after about ten miles bike just dies still has power to coil lights and accessorys turn key off and on bike backfires and starts up could it be ignition have dyna s ignition in it
You can test the ignition.
Start with a cold engine. Remove the ignition cover. Use a heat gun to warm the ignition module with the engine idling. If the engine dies the ignition is most likely the culprit.
Careful to not melt the ignition module.