CT70 runs, won't idle?

[69ST]

If you have less than, say, 20 minutes total runtime on this cylinder, then you should be able to just source a new 6v/"short rod" piston & rings. Much more than that and the cylinder should be deglazed, or the new rings may never seat fully. If you lack access to a dingleberry hone, of the required size, then it'll be easier/quicker to just source another cylinder. Might be a good excus....ummm...reason to source a bore-up kit (52mm/88cc) instead and enjoy a bit of added giddyup

 

[mk2davis]

To answer the question on everybody's mind, no you cannot simply run the stock piston in the aftermarket head. The Chinese head is roughly .030" shallower than the stock one, and therefore the piston doesn't rotate over center.