Using Deve's method, this is what I found (see pics).
Correct me if I'm wrong but it does appear to be a 12 volt/168 tooth flywheel (5 teeth per 1"). If so, then that kinda confirms what the previous owner was trying to achieve, albeit hit and miss with the potential for ring gear damage. He was also using 6 volts at the time. So when I converted to 12 volts it was further pushing the envelope, huh.
