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Marker Disc on Inner Timing Cover
#788451 10/28/19 3:59 pm
Joined: Oct 2019
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Carra Offline OP
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Hi All,

I have a 1965 reg A65 Lightning with an A50B.4**7 frame number and a A65 .D.C. 2**2. engine number, on top of the inner timing case cover there is a disc screwed on with 7 & 10 stamped on it, as per picture below. I am not sure what it signifies, I have heard it may be something to do with the gearbox ratios but also heard mention it may have been fitted after bench testing.

Has anyone any idea what it actually signifies.

Thank you

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Re: Marker Disc on Inner Timing Cover
Carra #788452 10/28/19 4:12 pm
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The bench testing story is a myth. The disc records the ratio of the speedo drive gears in the inner timing cover of the 1962 - 65 A50 and A65s. In 66 the speedo drive moved to the rear wheel. The drive gears are set up to correspond with the wheel rim and tyre size of the rear wheel to arrive at the correct drive ratio for the speedo. For example Lightnings and Cyclones had a 19" wheel with a 3.50 tyre, Star twins had 18" wheels. Early models had Chrono speedos and 64/65 models had magnetic. The gears are listed in the parts book.

Hope this helps

Last edited by VicCyclone; 10/28/19 4:14 pm.

VicCyclone

1965 A50 Cyclone Clubman
1966 Victor GP
1967 Victor Special
1968 Victor Special
1968 A65L

2009 HD FXDC
Re: Marker Disc on Inner Timing Cover
Carra #788455 10/28/19 4:21 pm
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Good to know, I have always wondered this myself.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Marker Disc on Inner Timing Cover
VicCyclone #788456 10/28/19 4:27 pm
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Originally Posted by VicCyclone
The bench testing story is a myth. The disc records the ratio of the speedo drive gears in the inner timing cover of the 1962 - 65 A50 and A65s. In 66 the speedo drive moved to the rear wheel. The drive gears are set up to correspond with the wheel rim and tyre size of the rear wheel to arrive at the correct drive ratio for the speedo. For example Lightnings and Cyclones had a 19" wheel with a 3.50 tyre, Star twins had 18" wheels. Early models had Chrono speedos and 64/65 models had magnetic. The gears are listed in the parts book.

Hope this helps


That's what I thought , thank you very much, it was just bugging me, you know when someone puts that little bit of doubt in you mind!

Thanks again


Moderated by  Allan G, Jon W. Whitley 

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