hi,one for the paperwork collectors,a genuine bsa invoice
for an m21 dated 1937,complete with extras and accessories.
henk likes old papers i think,nice bit of history.
even better if you can match it to your bike.
290686305911
cheers rick
Kalle. There is something about BSA changing their wheel/tyre size to 400x18 and slightly different length top fork links for side-car use.
A 400x18 tyre will give roughly the same diameter as a 325/350x19 tyre, but with more tread on the ground and I guess a bit more springiness. Ron