I really am stumped on this one. I am riding along just fine and all of a sudden the motor starts to backfire & loose all power. I pull over to the side of the road & it's idling just smooth as a baby. I then continue on without another problem. However, I now have ZERO head and passing lights. They are toast! all filaments have been blown! The turn lights, fender lights & stop light are fine. I replace all of the blown lights with new bulbs (not cheap!) and a couple weeks later the same thing happens again. All lights blown. These are the conditions when this happens: 1. I'm on the highway going 60-70 mph. It has only happened at these speeds. Never at street speeds. 2. I have been going that speed for anywhere from 5 to 15 min. before the event happens. 3. When the event happens, the motor sounds like it has blown a head gasket at speed but is just fine by the time I stop the bike. I don't think the problem is a short because that would not blow a bulb. I'm thinking it could be a voltage regulator, however, why didn't it blow ALL of the bulbs if it was that? I really need some help here. If anyone has any ideas, please let me know. To keep buying new bulbs ($20.00+) is not an option!