Hi Grumpy, thanks for all that info. (I didn't think of a helicoil, mind you there's not much left in there).

The JAP engine number is 80/0 101157/71. It also has 'B' and 20302F stamped on the front.

Stamped onto the ID plate is DR15755C.

I have attached pics of the engine, carby, cone clutch and roller. I cleaned up the roller with acid last night and temporarily primed it. You can see it is fairly pitted along its length where it has been sitting on the ground. The rest of the roller is in very good condition.

Cheers
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