Magmo Speedos

[John A]

Have stripped my Magmo with grateful thanks to the instructions given by Mike Davis of Cornwall 7 & Ron Hayhurst of Bristol 7, but just wondered if anyone knew what function the 2 rivetted arms on the face plate perform.
Hopefully the photos which I'll try an attach to this post, showing both face plate and speed disk will show the arms in situ, and the part circular grove that has been scribed on the disc.
One of the arms (l/h side of faceplate) is quite stiff, the other is not and I thinks the one that marks the disc.
So do both bare on the speed disc and for what purpose?
All advice gratefully accepted.
Many thanks John H.        

[GK5268]

The right hand-side one, is aluminium and is very fragile, I think its purpose is to lightly dampen the disc. Not had mine apart recently and don't remember off-hand what the other one does... it may be the limiter for the disc.

New numbers for the drums were available on-line, I bought a set (but haven't got around to fitting as yet), while it is all apart would be a good time to fit if you can get them, not sure if there is a transfer for the disc available, mine is like yours!

[Bob Culver]

Without the light one the drum rolls back and forth at speed. I seem to recall it does not come into operation until a few mph up. Decades ago with a ragng Wellington tail wind and a rolling drum and when our speed limit was 50 or 55 I got pulled up by a cop and asked if I was aware of speed (60mph!) Sadly I did not insist on a ticket.