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EuroIron
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VBMWMO #7266
Joined: 04/23/2007
Posts: 414

can anyone articulate or illustrate the differences in the post war singles' charging systems?

I am thinking the R24 and R27 are unique and different from the others

thanks if you can and/or will

niall4473
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Lancashire, UK
Joined: 04/09/2007
Posts: 94
BMW singles Charging systems

Hi Euro,
Don't know too much about this I'm afraid, but in the absence of any reply from anyone who knows what they are talking about, here's my shillings worth.
The R25/3 and R26 definitely shared the same unit which had the generator, coil, CB unit and CVC all in the one unit, normally with a silver tin cover over the front, the earlier bikes had a smaller one with a black cover of lower output, presumably the rotor and field coils were shorter, I'm not sure but i think that some or all of these had the CVC unit remote out on the bike, like a Lucas or Miller equipped Brit bike.
The R27 had a similar generator in an ally housing bolted on to the crankcase, this moved the stator outboard, (I think) so the crank is different, but the points went on to the end of the camshaft, which then had to have an automatic camchain tensioner to prevent erratic timing, I don't know about the coil or regulator, although I expect they were in the same place. These developments were, I believe, a spin-off from Isetta development. Why, I wonder, did they not put the Dynastart on it as well?
What I can tell you from personal experience is that the generator on the R26 can generate more than enough heat to set on fire and that this can be very embarrassing, especially if you have to get towed home by an Ariel Shedmaster.
If you are interested, I can also tell you how to replace the (unobtainable in UK) original generator with an alternator from a CB250K4 Honda. When I get my camera back off my daughter I'll post some pictures of this conversion, if you like.

__________________

Oil is always cheaper than metal

EuroIron
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VBMWMO #7266
Joined: 04/23/2007
Posts: 414
BMW singles Charging systems

thanks and I'd love to see the conversion

something like that is right up my alley and sounds just like something I'd think was a great notion

good enough I'd even perform such an abortion!

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