Since last fall during rides I have on occasion, noticed my check engine light on and the LCD display off or flickering, then everything is normal. It would only do this for a few seconds and then back to normal, maybe only one time on a long ride. Eventually I noticed that my headlight would be out when this was going on. This started happening with more frequency but still only lasting a few short seconds and I was never able to duplicate it or get my volt meter on it when it was acting up and the engine never acted up at all.

I installed a HID headlight system last summer so I pulled the fuse on it to try to eliminate the last thing I did but that is difficult to verify since riding around with no headlight will get you pulled over around here but I was able to verify that the problem was not the new headlight system.

I started keeping the voltmeter close at hand and finally was able to get it on the system when this happened and found the voltage at the battery was over 17 volts and climbing!

I shut it down and cranked it back up and the system voltage checked normal and everything worked. I rode it for two hours with the volt meter taped to the handlebars and it never went out of normal system volts.

It happened again a few days later and I was able to verify the voltage regulator output had failed and I tracked the runaway voltage going through 16 volts before the check engine light came on and the LCD quit working. When it went through 17 volts, I shut it down.

This is the third OEM voltage regulator in five years that has failed on this bike. That seems a little high to me. I figure I have nothing to lose so I installed a cheaper aftermarket regulator and the system is back normal again.

 

Interesting. Thanks for the report. I so hate intermittent electrical problems.

I wonder what is causing the failures...

 

Replace the main circuit beaker. It's flaky and what is killing the regulator. Also check terminal lugs and main wires on the circuit breaker. The main circuit breaker isolates everything including the regulator from the battery. If connections are loose or flaky the regulator / charging system can feed too much peak voltage to the electrical system. I would also check grounds.