Sounds like a weak battery. Do you have a load tester? Do you have a lot of electrical accessories added, ie driving lights or light bars? The stators on these old bikes do not produce that much watts able to run lot's of accessories. Install a volt gauge to be able to keep up with how the battery/stator is performing. The stator should be producing 14.5 volts at 2000 rpms. I have kuryakan led volt meter on my 1100. If I'm not showing a green light, I'll switch off some accessories to get a good charge. All my accessories are switched to be able to turn them off or on as needed.