The shape of the fueltank looks indeed very much the same as the later fueltank. I will compare them to see if it's the same pressing.
BSA did make an instruction book for the Dutch Army M21 and G14 motorcycle's. I have the instruction book for the M21, see photo's below. Nice detail on the one I have is that it was in the possession of the "Chief of the workshop Staff Sergeant G. van Rees". I am not sure if a specific Dutch/M21 partslist was printed, I know for sure the Dutch Army ordered individual parts based on the 1938 partslist. In a document I found in the Dutch National Archive the Army is requesting the BSA factory to send a 1939 partslist, request is dated 31 March 1939.
The Dutch Army had a small amount of M21 and G14 spare parts in stock. The parts were stocked in Delft, very near to a large workshop of the Army. These parts were provided on consignment by the BSA company, every year the Dutch Army would pay a certain amount of interest and paid for every part which was taken from the stock. After the Netherlands was occupied, this stock was 'übernommen bei Wehrmacht" as it was stated in the administration. The workshop in Delft remained in service during the occupation with a part of the Dutch civilian personnel, complemented with German personnel. See photos below of that workshop, a G14 is on the bench and the other is taken in front of the workshop.
I have just started my WM21 for the first time, it went quiet ok. I had to adjust the carb and then it started on the 2nd kick. Hereby a few photos of the result.
An absolutely splendid effort - very well done indeed. One small point I would appreciate your confirmation on relates the the speedo drive which I would have expected to have been through the front wheel brake plate whereas on your bike it is taken from the other side. Thanks.
The location of the speedo drive on BSA's changed in September 1939 with the introduction of the 'W' series (sometimes refered to as the '1940 model). The 'K' model (1939) had the speedo drive on the right side through the brake plate. Approx 370 KM21's were delivered to the Dutch Army till September 1939, these had the speedo drive in the front brake plate.
All WM21's delivered from the 1st of September 1939 did have the speedo drive on the left side. My WM21 is delivered to the Dutch Army in March 1940 and would have had the speedo drive on the left side.
Hereby a photo of some WM21's in use by the Dutch Army. The speedo drive cables are visible, these are located on the left side.
Thank you for sharing that Bastiaan, the front of the cover is interesting it says "Model 1939 M21", there are few references in the BSA KM ledgers for "M39-20" which may have a connection?
In total 10x BSA M20 were delivered to the Dutch Army, 7 of them were with handgear change and in 'army green' as mentioned in the ledgers. I expect that the other 3 were also with handgear change and in army green but it's not specified in the ledgers.
4 of those M20's were delivered to the Corps of Motorcycle Service (Korps Motor Dienst), these all had handgear change
1 of those was delivered to a unit/department which was abbreviated as 'A.M.A.' I have no clue yet which unit/department this was