Is there a view of the other side of it ?
Firstly, its rigid frame.
So likely to be circa ~1950 or so.
2ndly, the clutch is on the 'wrong' side, so its unlikely to be British.
3rdly, that engine is SMALL (and very neat), so likely to be 50cc (?).
Very popular in Europe since WW2.
Hand gear change may put it into the 1930s however.
Those pressed front forks look like a european style.
German in particular ?
This narrows it down to only a ~ million (?) types !! ?
Is there a detailed view of the handlebars. ?
Even this can tell a lot.
Can you test if any of the nuts/bolts are metric ?
A VERY careful rust treatment of the tank may bring up some colours and maybe even decal remains ?
Phosphoric acid, gently dabbed on and lightly rinsed off is very good for doing this. As is oxalic acid or even vinegar.
I'll thumb through Tragatsch later on, if it doesn't click with someone.
Hopethishelpsabit !
