Eletrical Woes

[Katamaniac]

I have a friend that has a 1980 Yamaha Maxim and he has had trouble with the electrical system lately. It seems that his headlight will not work some times as well as his tail lights. He also found that if he unhooks his headlight the bike won't run. He's checked all the obvious (replaced all fuses, checked wire connections etc.) Sometimes after hitting a bump things will start working again or it will knock something else out.

He also had it shut down on him for a short period and had only power to his tail lights.

I know this is a Yamaha, but you guys are awsome. I just need to see where we need to look to get this thing going again.

[chiphead]

A wild guess is a ground circuit that is loose. Try running an additional ground right from the negative side of the battery to a clean tight spot on the frame. Use a heavy gauge wire similar to what's in place now.
This is only a guess. Your mileage may vary.

[steve-lloyd]

chiphead is almost certainly right. I had the same thing happening on an old Kawasaki Z440 and it turned out to be a poor ground, even though it felt tight and looked ok. Make a good ground to a REALLY CLEAN point, use wire as thick, or thicker than the original, and connect it up really tight and you should be OK.:-D

[2005JJT]

I spent 4 hours last night with this same issue. Check all grounds. Unscrew all and scratch the surface with a screw driver to expose bar metal. The one last night looked perfect no rust and tight. I kept the lights and key on as I took off each one. After cleaning the last one (of course) all my lights and switch came back on. No issue since. Good luck....