Sure sounds like it's over charging. Do those bikes have a regulator as well as the rectifier? Or a capacitor that soaks up the excess charge?
Nice job on the vid.
2014 Kawasaki KLR650 NE-2000 Buell M2 Cyclone-1996 XR600R-1993 Kawasaki KX500-1984 Honda XL600R/XR650L Hybrid-1984 Yamaha TT600L-1977 Yamaha TT500-1980 Honda CB750F