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Original Vincent ATDs With Steel Covers

A_HRD

Well Known and Active Forum Website User
VOC Member
Given all the chat about ignition timing/magnetos and ATDs, I decided it was time I raised this issue, without hi-jacking someone else's thread.

Did anyone out there know that a few of the earlier Series B Vincents had a special ATD fitted in that it had a steel cover over it, presumably to collect any debris in the event of a catastrophic failure? The one in the photos came to me from the original purchaser of a 47 Rapide who lived not far from here. In 1949 he removed the mag, ATD and 276 carbs to replace them with coil ignition and TT carbs respectively - so that he could go racing. And that is the way the bike stayed until he sold it 2 or 3 decades later. However, years later again, I was able to purchase these parts (plus 5 gallons of Castrol R - that should gladden vibrac's heart) that he'd packed-away carefully in a shoe-box.

The ATD and fibre gear is in pristine condition having had only a couple of years use. The springs are surprisingly taut and the action silky smooth with no undue looseness or rattles. The cover fits with barely a thou between it and the fibre gear - so getting this dimension right would have been quite traumatic (because the cover moves relative to the gear. I guess it was that, or the inability to see the workings or to wedge open the mechanism to time at full advance, that led to the cover's demise. Subsequent ones of course have the cut-down version resembling a washer.

There was a period m/cycle magazine in the late 40s with a Lucas advert showing this covered ATD, but I can't seem to find it. Can anyone else shed any further light on this curiosity?

Cheers,

Peter B
Bristol, UK.


P1030879.jpgP1030882.jpgP1030878.jpg
 

derek

Well Known and Active Forum Website User
VOC Member
Does anyone have a graph of the standard advance curve for original ATD?, or know at what revs full advance was achieved.
 

b'knighted

Well Known and Active Forum Website User
VOC Member
Did anyone out there know that a few of the earlier Series B Vincents had a special ATD fitted in that it had a steel cover over it, presumably to collect any debris in the event of a catastrophic failure?

Taking into account the level of response, I think it may be fair to actually answer your question, on behalf of everyone else - No!
 
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Photos from the 2022 North American Rally

Photos from the 2022 Annual Rally

Photos from the 2022 French Rally


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