John asked me to post the picture of his engine and the email that I sent him. So here we go, Ctrl C - Ctrl V... 😃
Hi John,
Now this is a good question! 🤔 Intuitively I would say that the original engine number would have been WM20.79068. The “WM20" prefix was stamped “en masse”, while the actual number was stamped individually. That’s why the prefix (WM20) and number (79068) are often not aligned, sometimes they even used a different set of numbers with a slightly different size for prefix and number. And on this engine the prefix was “loud and clearly”, while the number is very faint, unusually faint even! Why…? The typeface of the number 79068 looks correct by the way.
And then somebody overstamped this number 79068 with the number 7244. I don’t think it was the other way round, as I think it’s logical that the correction is more visible than the original number that is being replaced… Now who could have done this? The factory? An Army workshop? A post war dealer who was trying to create a “matching numbers” bike…?
- The factory would be unlikely. The oldest number should be the smallest number (7244), the new number should be the highest number (79068). But why would the factory have stamped a number so faintly? I have to say that I’ve never seen anything like this before (such a faint number).
- The Army workshops: also unlikely. The Army didn’t care about “matching numbers”, after an Army rebuild the numbers were ALWAYS mixed up.
- I think it may have been the work of a post war dealer. He had a frame with the number WM20.7244 on it, and an engine with the number WM20.79068. To prospective buyers a “matching numbers bike” gives the impression that it has been well cared for. Non matching numbers give the impression that it’s just a quick mishmash. So easy peasy, just overstamp the (faint) original number… And there are lots of examples of this practice during the late 1940’s - early 1950’s. But the question remains: why is the original number so faint…?
There may be another way of determining which engine this is. Every factory that was working for the Ministry of Supply was inspected by a MoS inspector. Some factories had a resident inspector from 1940 up until 1945 (Royal Enfield did), this resident inspector was replaced every 6 months (approximately). Every inspector had his own unique inspector’s acceptance marking, which is a broad arrow over a letter M over a unique number. On a Royal Enfield I can date an engine only by looking at the acceptance marking. The problem with BSA is that they were not as consistent as Royal Enfield. It looks as if not every bike was inspected. I’m keeping a database of these acceptance markings, and I can see that engine WM20.78362 was inspected by M397, while engine 80129 was inspected by M54. If your engine would have been stamped by one of these inspectors, we can definitely say that the original number was 78362. The closest number to 7244 that I have in my list is 10100. This bike was inspected by M89. Such a stamp on your engine would mean that the number 7244 is original. But it is of course not impossible that your engine has no acceptance marking at all...
Here’s a screenshot from some of the numbers that I have in my database, to show you the “typical style” of these numbers. I can assure you that all these numbers are genuine:
The BB stamp by the way is very common on WM20 engines. It is generally accepted that this is a BSA inspection mark.
Hope this helps! If you wish I can post your picture on the forum, maybe there’s somebody who can add something to this discussion…
Cheers,
Jan
email (option): wd.register@gmail.com