So those wire combinations jibe with the headlight relay connector, the key switch itself should have 3 wire connector: red, brown & blue (according to US '81 model now on that part only). No matter, as the result is the same; too much voltage drop. I don't know if 10 volts at the regulator (and rotor) is enough to get the alternator charging.....@ Jim, et al??
You could bypass the key switch with a temporary jumper at its connector - red to brown - just long enough to see if it cures the voltage drop and produces 12V on brown @ regulator. If it does that, I think you should then get full magnetism at the rotor.
You could bypass the key switch with a temporary jumper at its connector - red to brown - just long enough to see if it cures the voltage drop and produces 12V on brown @ regulator. If it does that, I think you should then get full magnetism at the rotor.