I think the name on the keys will read 'Neiman' – it is a german manufacturer well known for its motorcycle steering locks, e.g. http://guzzino.com/stfolone.html . Most german motorcycles from the post-war era had those Neiman locks fitted (my 1971 BMW R 75/5 has one of these, too). Most astonishing fact is that they are still in business today … Did you already check the threading of the wing nut ? As coaster hubs and geared hubs are very popular here in Germany, it may well be that the wing nut fits one of these. But anyway this special lock is a nice and very rare find !
Via Bicycle 
Now this is way to cool!
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But when you get to cool, then what?
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I think the name on the keys will read 'Neiman' – it is a german manufacturer well known for its motorcycle steering locks, e.g. http://guzzino.com/stfolone.html . Most german motorcycles from the post-war era had those Neiman locks fitted (my 1971 BMW R 75/5 has one of these, too). Most astonishing fact is that they are still in business today … Did you already check the threading of the wing nut ? As coaster hubs and geared hubs are very popular here in Germany, it may well be that the wing nut fits one of these. But anyway this special lock is a nice and very rare find !
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