Motorcycle Repair: 85 Honda Shadow 500, volt ohm meter, light sensors

Question
I had just jumped started it because battery died, I don't know why it died. It starts but when over 3000 or so RPM the brake light turns on the dash and the bike seems to be back firing and signal lights don't work. At idle, the bike turns to normal. Could this be the Voltage regulator?

Answer
I've never heard of the voltage regulator causing that problem but that's about the time manufacturers started to add more electronics like rear brake light sensors. It's an easy thing to check.  Charge the battery enough so it can crank the engine easily and start the bike.  Take a volt ohm meter and hold it on the battery terminals and rev the bike up.  The voltage should not go over 14.5 volts.  At idle it will be a little lower because the alternator may not put out enough amperage to run all of the accessories depending on what is turned on.

Let me know what you find.