Very slow voltage drop..

[luke]

So I have about 50 miles on my build and everything was going great until I stalled today and noticed my headlight was very dim...

I waited a few minutes and the bike fired first kick and I was able to get it home.

If I start the bike now I can slowly watch the voltage at the battery drop..
Rotor tested fine..Any ideas?

 

[XSLeo]

Brushes, bad wiring, stator, regulator, rectifier, fuses, connections.
What your bike is will help, year, model, modifications done, stuff like that.