Forgot to add you want around 12-15V AC coming from alt and around 15V DC coming out of rect (a bit either side is ok but it it's way off things are knackered). I don't know what the resistance on the wires should be with your bike that should be in the workshop manual.

I'm no guru on this just had a similar issue recently that turned out my pickup was knackered (really dodgy Chinese wires). You may want to double check my figures with your guide or an owners club etc.