Yep, voltage regulator, sometimes it's just a bad ground. It's on the inside of the right foot rest attached with a couple of bolts. I think mine on my xc needs to be cleaned up and remounted as it may have a little corrosion or just a bad ground. The Last 2 years, the headlight on my xc flickers until is been run about 20 minutes for the first time out on the year. Then it's fine until next winter.