rrperry001

I fixed it this weekend and that was the problem. I have been asking people for years and no one suggested the brushes, so i just started taking it apart and found one completely gone. When i replaced it, it worked however the surface it rubs on was coming unattached in some places and was probably the cause of the brush wearing out so much more quickly then the other one. Any idea for a good fix for this problem?

My 1975 Yamaha RD 250 worked fine when i got it two summers ago. While on a road trip my head light got dim and the engine eventually died. I let it sit for a few minutes and restarted it. At that time the headlight was bright and it worked fine, i made it the 100 miles home. However the next day i started it and it ran for about 20min and died. I tested the output going to the battery and there is not voltage going to it. I can charge the battery and the bike runs fine till the voltage drops to amount 5.5v. The local shop charges 85 bucks an hour and doesn't usually work with vintage bikes. Electrical parts for this bike costs up to 500 dollars. I am an engineering student and am component with electrical systems and monitoring equipment. I just have no idea where to start(i obviously checked the fuses and looked for any obvious shorts. I did get caught in the rain on this trip but it didn't quit working till the ride home a week later. Help please! the bike is basically worthless as it now is. It is in mint condition with only 6000 miles and is a blast to ride.