Author Topic: Lighting Generator Drive  (Read 3465 times)

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Offline Resto-Rob

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Lighting Generator Drive
« on: 13 Nov 2012 at 12:58 »
Hey guys,

Yet another horrifying discovery on my C32!!!

The previous owner has removed the drive gear that runs between the magneto and the lighting generator!! The only reason i could see why anyone would do this is that the generator is stuffed!!!

Would anyone know what the drive gear looked like? how many teeth does it have?? I am guessing it would be near impossible to find a replacement so a new one will have to be made :(

I will never again buy a motorcycle without seeing it first!!

Offline Resto-Rob

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Re: Lighting Generator Drive
« Reply #1 on: 13 Nov 2012 at 13:18 »
I have just come across this post.  Could anyone tell me if this is the gear i am after??

https://www.douglasmotorcycles.net/index.php?topic=3495.0

Offline Doug

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Re: Lighting Generator Drive
« Reply #2 on: 14 Nov 2012 at 01:16 »
Rob,

Yes, the C32 would use the same cone clutch drive built into the face of the magneto gear wheel. On the dyno would be a small pinion. If the same as the other lightweights (and no reason to assume not), this would be 14 teeth.

The drive was probably disconnected because even when all was operating properly, the BTH pancake dynamo put out all of about 22 watts. Perhaps a telling bit in the advertising of the lighting set was the following:

Quote
"The system is simplicity itself with the added advantage that the generator can always be removed and the fixing hole blanked off, which means the machine need not be out of commission should a slight defect become manifest in the generator."

Almost seems they anticipated troubles! Anyway, the output is pretty meager and rapidly approaches nil if there is any problem with the armature or the magnets have lost their strength (or cracked, introducing extra north-south poles).

-Doug

Offline Resto-Rob

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Re: Lighting Generator Drive
« Reply #3 on: 14 Nov 2012 at 11:09 »
Thanks again Doug,

Do you know if there is any solution to this age old problem of the BTH dynos being rubbish??
Is there a more reliable replacement out there or perhaps a more modern solution??


Offline Doug

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Re: Lighting Generator Drive
« Reply #4 on: 14 Nov 2012 at 12:16 »

Offline Resto-Rob

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Re: Lighting Generator Drive
« Reply #5 on: 14 Nov 2012 at 12:48 »
Thanks again, i have been doing some searching on the web and it seems there isn't an early 30's Douglas out there with a working BTH Dyno...
I will still need to try and get my hands on the missing gear from my bike for when i want to build a new "funtional" dyno.  For now, i guess i should stock up on charged batteries?! :)
Thanks again Doug!