piston size, next bore

[Ton76]

Hi,

I've just disassembled the cilinder and head of a KR50. Apart from the fact that I didn't find any gaskets at all it seems that the cilinder and piston are in pretty bad shape.

The piston is marked 38,43. Is this the original piston size? And what's the next piston size for a rebore?

Thanks!


Greets,

Ton

[Roadrunner335]

Welcome Ton!
Where're you from?

The "original" piston should be marked ~37,93, so cylinder is 38,00
So it seems that your cylinder has already the 2.rebore (38,43 piston; 38,50 cylinder)
Next would be 38,63 for piston, 38,75 cylinder (3.rebore)
It goes up until 6.rebore.

[ramirez93]

Hi Ton,

although i do not know the answer, you should introduce yourself first. That is the normal way. It will increase the chance of getting right answers. I think everyone wants to know, where you are from, and why you have a Simson bike.

...good luck and have fun...

ramirez

[beep!]

Hi Ton

If you need any gaskets or parts like the cilinder, you must look at www.ebay.de

[ramirez93]

really? i would wait to get them here!

[ddrschrauber]

Between the cylinder and the cylinder cover there ist no gasket.

Der Tim

[Ton76]

Hi all.

Excuse me for not introducing myself. I'm from Holland. Den Haag to be presice.

The kleinroller, as you call it, is a KR50 from 1963. It's my girlfriends scooter and I'm getting it on the road for her. She bought it 2 years ago as a non-running show model. So the exterior looks good but the mechanical condition is pretty bad. Fortunately the engine seems to be in good shape. Not to say about the cilinder, piston, carburettor, wheel bearings, etc.

I'm new to DDR bikes. I usually work on British and Japanese motorcycles wich are, to say at least, slightly different from this Simson.

I've already had some email conversations with NorbertE about axle modifications. That problem is soon to be fixed. Thanks Norbert!

By the way, is it normal for the throttle grip to slide off the handle bars at idle all the time? I don't seem to get it fixed even after buying a new kit. It looks like the classic maguras used on Puch MV and Tomos 2l models but they don't seem to work that well.

Greets,

Ton