BSA Bantam?

[PeterT]

a very controversial subject is that BSA copies MZ's RT125 engine design by Walter Karden for the first Bantam engine.
[/quote]

My research claims the same, as dmw says 'copied from a German design'. I also see this info was supressed because WW1/WW2 !!
BSA tried to improve on the 125 power but failed and upgraded using, once again, the German model.

[Dogsbody]

a very controversial subject is that BSA copies MZ's RT125 engine design by Walter Karden for the first Bantam engine.
It was actually the DKW RT125 design that Britain received as part of the reparations after WW2, to be pedantic.
I currently have a B175 on the bench as we speak and restored a 175 about ten years ago. Worked on quite a number of Bantams in the 1960s, 125, 150, and 175 along with C100, C50/90 Hondas, Triumph Terrier and Tiger Cub. All used as commuter bikes.

[PeterT]

I currently have a B175 on the bench as we speak and restored a 175 about ten years ago.

I've been offered a 3 speed 150cc bike. 1957 D3? ..... The guys done a fantastic prep job on the parts but ill health means he can't re build.

[Dogsbody]

Suggest you read this book to find what a Bantam can do. Makes Ed March et al look like amateurs.
http://www.gasolinegypsy.co.uk/

[PeterT]

Awww thanks for that link DB .... Bantams are not forgotten then