I think it helps if you can share a photo of the engine number. I have 3x original WM21 engines all delivered to the Dutch Army. Engine WM21 377 was delivered to the Dutch Army on 22-11-1939.
British Forces Motorcycles By Steve Madden and Chris Orchard.(O&M) We're on the third edition now. Available on ebay I guess. It seems they didn't note the Dutch records. So you have a nice find. Ron
The number looks genuine to me. I have bought a WM21 engine a week ago with a single 'B' stamped roughly on the same place. The 'B' was also stamped on the timing side of the crankcase. Do you have a photo of the timing side of this engine?
'B' for 'Base workshop' is a little strange for an engine which was delivered to the Dutch Army. I have found my engine wit an 'B' in Poland. I have found many Dutch Army M21 parts in Eastern Europe, that is the place where most Dutch Army M21's went after the Germans confiscated them.
As mentioned during that other thread. The B on Matchless cases, indicated Bowden controls as opposed to Amal. Which can't be the case with BSA or Royal Enfield......Still no wiser....Yet! Ron
Interesting Jan, thank you for the link to the earlier posts. I think we can safely conclude that this stamping is not of WD origin/purpose but is more something which had a purpose from/for the factories.
This BSA is a very strange mix of parts. The engine is not genuine Dutch Army spec, the timing side of the engine casing is missing the hole for the fitment of the oil tell tale. There are 2 options in my opinion: 1. the engine casings are a non-matching set or 2. The engine number is later re-stamped.
