A7 Motor with odd Suffix

[Black Sheep]

I can confirm that BSA returned race bike spec stuff to the service dept. Some years ago I picked up a standard bore service exchange set of thick flange small fin barrels and pistons, normally only seen on Daytona machines.

[Joolstacho]

My late type pre-unit crankcases have no number at all. I was told by the feller who sold me the engine that when BSA supplied replacement crankcases BSA left them unstamped because they wouldn't know whether it would be used for an A10 or A7. Can anyone from back in the day confirm?
(Apparently it had been in a grass-track outfit which had previously had a blow-up).

[JulianS]

See below BSA parts bulletin from 1954, last paragraph - yes they came without numbers stamped.

Sorry its a poor copy.

[Joolstacho]

Well, mine must have escaped this bulletin (who'd be surprised? -It was probably friday arvo, - race to get down to the pub for a pint or six!)
(Note " should" not 'must') 

Oh, and I bet more than a few disappeared out the factory gates in lunch bags too.

[trevinoz]

This will give the purists something to think about.
There has been much discussion whether fonts on characters are correct from the factory or fraudulent.

[Klaus]

I have found an enginecase stamped DR 150069 CAL  this is not an Ariel Number.
Does anybody know more about this Number.
May be Daytona, its only a suggest.

cheers Klaus