As most forum posts will show tell you with a little searching is that the voltage regulator/rectifier on Yamaha motorcycles will eventually go bad. Thankfully an hour or two is all it takes to replace this part.
I figured my rectifier was going bad as when I would drive at night my headlights brightness was changing as the RPM’s increase or decreased. This would take a few minutes to kick in since the rectifier either had to get warm to start failing or would get jostled.



