Author Topic: Disassembly of Auto Advance Unit ?.  (Read 5059 times)

Offline rocket man

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Re: Disassembly of Auto Advance Unit ?.
« Reply #15 on: 10.10. 2009 11:11 »
i have a question why did they make them fiber was is to make them less nosey
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Offline flashblack

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Re: Disassembly of Auto Advance Unit ?.
« Reply #16 on: 10.10. 2009 11:43 »
I always thought it was to protect the mag in case the engine locked up. Years ago my drive chain snapped and locked everything up and stripped the fibre teeth off!

Richie
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Online groily

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Re: Disassembly of Auto Advance Unit ?.
« Reply #17 on: 10.10. 2009 22:24 »
Reckon Flashback's theory is the most-often-stated one . . . but how many manual mags used fibre-drive? Haven't met a plastic sprocket or chain yet. So the built-in 'first point of failure' argument does not work for me. And yet, so many manufacturers went with the fibre option for twins. BSA, Triumph, Velocette, Vincent even. I have no real idea why. Norton twins managed with chains and steel like any good sado-masochist, so did Royal Enfield, AMC ran steel pinions on twins. Nobody apparently told them they shouldn't. Fibre's quieter, almost for sure, but that's about it. And when there are up to six pinions in the train for any bog standard twin camshaft motor, what's the difference in practical terms? Maybe it was Mr Lucas who proposed it, as I imagine he sent the ATDs ready assembled to the factories. All I can say is I wish he hadn't.
And another thing - Magdyno pinions for the dynamo . . . yuk.
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Bill

Online Brian

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Re: Disassembly of Auto Advance Unit ?.
« Reply #18 on: 10.10. 2009 22:38 »
It doesnt make much sense, BSA used fibre on the twins but steel on the singles ????

I have a alloy one in my 61' A10 and its no noisier or anything. The reason they used fibre I think is one of those things that come under the heading of    "it seemed like a good idea at the time" 
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