Fanscinsting! Perhaps we will just have to imagine RW stands for Runs Well, and BB stands for Beautiful Bike. I’m hoping someday some information can be gleaned from some untouched resource; but I won’t hold my breath.

The grouping is interesting. I would love to try and compile a list of number that include these additional stamps, and see if perhaps there is a trend.

email (option): Moses@folkhogan.com

As the stamping seems to be much more uniform than BSA factory stamping and done in exactly the same font plus stamped to the same depth and all in a nice strait line, I will add another suggestions
RW = Re Worked as in replacement crankcases
As the club registrar I have noticed that most faked numbers are stamped far better than BSA factory stamps & always suspect stamping where all the impressions are the same depth , in a strait line & evenly spaced
Usually the model number , "wm20" in this case would be done with all 4 dies in a single tool holder as this means it is a 1 hit job so saves a lot of time
On latter engines I have also noticed that the first 2 or 3 numbers seem to be held in a single tool and the final 2 or 3 seem to have been done freehand
Like everythng BSA this is not universally applicable , just some thing I have noticed over doing hundreds of registrations in the past 30 years
Back in the high BSA thieft days it was common to slip an extra digit between the serial & model numbers to rebirth a stolen bike .

The “Re-Worked” theory is something I had considered. I wasn’t aware there was a lot of theft in the past; but it’s certainly not hard to imagine.

This particular specimen was fairly stripped down when it was discovered in a chicken coop, by my father in 1983 in Goshen, Utah, USA. At that time it didn’t have the following parts:

Fuel tank
Oil tank
Mudguards
Toolbox
Saddle
Battery or battery case
Headlight
And much more


It had been turned into a chopper, with the original girder forks being extended and welded, and it appears many of the original parts were long gone. My uncle is a motorcycle mechanic, and set to getting it as back to normal as he could given the available resources.

email (option): Moses@folkhogan.com

I think Trevor is probably right, a later war or postwar replacement crank case, the two examples shown above are over 15,000 apart so very unlikely to have been done in the factory in such a similar way.

Rob

email (option): robmiller11(a)yahoo.co.uk

Has anyone seen this before. It's a Flea that Mark Mumford is restoring for a friend. I think it's from the 1000 from the last batch that were canceled by the WO. Ron

email (option): ronpier@talk21.com

Very interesting. The REME WORKSHOP was posted about above.

email (option): Moses@folkhogan.com

We still don't know what the RW abbreviation stands for, but I have now found four data plates (3x1959, 1x1960) referring to this RW, which must have been a military workshop. It is currently still unclear where this workshop was located (BAOR - West Germany or UK).

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

I have run some of these numbers through the keycards and the numbers on the rebuild plates appear to be engine numbers rather than frame numbers as the rebuild dates often seem to be after the disposal of the machine?

For the following numbers the key cards show

92934 02YE58 sold off (Allies CR?) 1953 Engine rebuilt 1959 (card 560b)
96377 05YE28 sold off Antwerp 1971 Engine rebuilt 1960 (card 568b)
108654 10ZC39 sold of MELF (Middle East Land Forces) 1955 engine rebuilt 1959 (card 467a)
85610 not in the key cards but rebuilt 1959 after the key cards were created

email (option): robmiller11@yahoo.co.uk

I have just been reading this thread, and my feeling is it could be Rhine Workshop.

It could be...37 Rhine Workshop ran from 1948 until the eighties...Ian

email (option): ian@wright52.plus.com

Here's a commemorative medal...Ian

email (option): ian@wright52.plus.com

That sounds very plausible, thanks for your input Gentlemen!

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

email (option): kocaho8941@nasmis.com

The post by Andrew seemed a serious reply, but it contains a spam link.

What the hell is going on with the internet these days and what remuneration model is causing all these posts with wanky links ?