Generator R51/2

[Ivo Hendriks]

Generator on my R51/2 is Bosch RD45/6 with electronic regulator. I have frequently problems with drained battery. Does someone know whether this generator has enough power to keep the battery from goiing empty when riding with head light on all the time?
Thank you all in advance
Ivo

[Prosper Keating]

You're asking a lot of ANY Bosch generator fitted to an airhead BMW if you ride all the time with your headlamp on, even when the sparks come from a magneto! Here in France, where safety nazis have seen to it that daytime headlamps are obligatory for motorcycles, old motorbikes pre-dating 1965 are exempt. That said, a generator in good condition ought to be able to power your lighting when you ride. Assuming that your generator is in reasonable condition, the problem might lie in the electronic regulator you are using. Some of the electronic regulators sold by classic BMW parts dealers are not up to the job and can even destroy dynamos. Mark Huggett sells the only one I've ever used that really works as well as the old electro-magnetic regulator.

Prosper Keating
Paris

[Ivo Hendriks]

As you say it may be the regulator. I only get 6.5 volt on the battery when run trottle half way. Most people say it must be about 6.7 volt.
Thanks for for reply.
Ivo

[Ron Long]

Ivo,

I replaced the original mechanical regulator on my R51/2 project with an electronic unit from Huggett because the original was not working. So far I have no problem running with the headlight on, but to tell the truth I usually ride in daylight with the parking light on, rather than the headlight. I keep a log of the voltage at the battery before and after each ride. I usually have 6.3 volts before the ride and 6.5 volts after. I did not restore the generator. I am hoping to put off rebuilding the generator itself as it will be a job removing it.

[Ivo]

Have replaced electronic regulator by new one from Motorrad Stemler. So far all OK. Voltage after a ride is about 6.25 V

Thanks you all