Hi hope everyone is okay I have a 1949 M20 with a sidecar I am have the dating certificate from Henk, I also have 2 more engines the numbers are zm201908 ,wm2002399 both engines crankcase numbers match which indicates they have not been apart. My bike is 1949 zm20.4711, engine wm20.10237 Henk verified these numbers 2020

wm2002399 must be a typo...?

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Very close to a bike of mine jan if it was 2399

Jo’b

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We need a correct engine number in order to do some research Ian...

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Sorry about that was a typo correct numbers are ZM20 1908, WM20 62399

I don’t have any post war records (XM20) but I may be able to help you with the WM20 engine: WM20.62399 rolled off the production line on June 23th 1942, as part of contract C/11101. This bike would have had census number C4666107 on the petrol tank. Here's a picture of C4666503 (WM20.62795), which was despatched from the factory on June 24th 1942, one day after your bike.

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