Doesn't anyone have a file of BSA engine fonts and inspection markings ? If this were a WD Norton, I'd be pretty certain of pinning down year and or contract. The inspectors were rotated on roughly a six-monthly basis so it's straightforward to confirm most re-stamped numbers as such...Fonts changed from time to time too.

There are no inspection marks on Nortons after W50000 suggesting that the practice ceased around mid-1942.BSA may have continued.

The Pathé film showing a number being stamped on the headstock of a Welbike at the end of assembly. It seems likely that although on most bikes it appears on the crankcase, it is actually a final approval marking for the complete machine.

Enfield certainly took machines back from the War Office after the war and rebuilt them as new with re-stamped numbers...I don't believe that I've seen any evidence of the large and mighty BSA doing that.

If that is an original stamping, and I doubt it is, way too neat & regular the it is machine 4534, nowhere near the end of the war

email (option): bsansw1@tpg.com.au

Yes, I started to compile such a file many years ago... Unfortunately not all the M20s have an acceptance marking (unlike the Royal Enfields). My BSA M20 list is quite short...

Gino's engine appears to have an acceptance marking with a three digit number, ending with 97 (first number too faint). This number does not appear in my list... So a plea to all M20 owners, please check your engines in search for an acceptance marking, and let me know! Only in this way we will ever be able to make a reliable "database"...

Jan

email (option): wd.register@gmail.com

Here is my marking. My engine number is 18693, but I suspect its a later engine re-numbered when fitted to an earlier bike.

email (option): richardpurkiss@hotmail.com

I assume that's our old friend M419 again...the numbers are usually central to the 'M' suggesting that the stamp on the corner hasn't impressed cleanly.

Unfortunately, a stamp on the timing side is never going to be positive proof.

Indeed Rik, this is another M419 stamp! Must have been the busiest inspector of them all! :grinning:

Richard has sent me a picture of his engine number as well, and indeed, this one has clearly been restamped. So unfortunately not useful for the acceptance markings file...


On the other hand, Richard's engine has a ^51 marking that is identical to the one on WM20.96341 in my list above. This looks like a BSA inspection mark, and this could mean that Richard's engine originally had a number close to this one…

Jan

email (option): wd.register@gmail.com

Hello All,

Don’t know if this has any relevance, another stamp not too far away from the other.
https://ibb.co/FHMf0tz

Thanks,
Gino.

email (option): gino_kerekes@yahoooo.co.uk

Apologies-

No idea Gino... A couple of years ago we've had a thread here on the forum with all kinds of unusual marking on BSA engines. Unfortunately all these pictures will now be useless due to the new Photobucket policy...

Jan

email (option): wd.register@gmail.com

Thanks Jan,
The thread has already been a great help to me.
It appears to me there are basically a couple of reasons how this engine ended up in my bike.

As mentioned in an earlier post, maybe after the war ended a surplus WM engine was restamped for use in a civvy bike.

Or, maybe at some point in time, the original engine was damaged and a WM engine was put in the frame and stamped with the original number.

Anyway, it’s part of the bike now, target for back on the road is before Christmas!!
Thanks,
Gino.

Ps, I also found this under the paint on the top tube.


upload images

BSA engines are literally littered with stampings.
Ones with a broad arrow were done by governement inspectiors.
All the others are normal identity or fit marks done at the factory so that parts which were machined as an assembly can be reunited for final assembly.
The other thing is parts were subjected to testing with a series of go / no-go gauges and in many cases would get a stamp according to which gauge fitted best then when assembled, the assemblers could pick parts that were the best fit with each other.
You will find them all over the inside of the engine.
And then there were date stamps.

email (option): bsansw1@tpg.com.au

Gino, that looks remarkably like weathered Khaki Green No.3 on your top tube...Have we seen a photo of the whole machine and of the frame number ? Is that an original stamping ?

In my experience of ex-WD bikes, it's not that unusual for owners in the 1950s or so to have replaced a damaged / bashed / blown up bike or major component with cheap old ex-WD stock and then simply transferred over the number from their logbook...far less trouble and expense but a puzzle for us, sixty years down the line...

Think that is a telescopic front frame, BR Michiel

Here in the US I've seen many re-stamped frames and engines but I sincerely doubt the motivation was as innocent as Rik describes.

Jeff

email (option): jjbandoo@aol.com

It's a mystery!
It does look like faded green in the photo, I'll take a proper look in the daylight to confirm. There is also some light blue in their!
Thanks for all your input & comments,
G.

email (option): gino_kerekes@yahooooo.co.uk