got my cylinder back

Maybe the rings are wearing out.

Did you do a plug chop.

I sure hope the piston is not being slowly fried, as a result of a small air leak not picked up because of a lack of leak testing.

If your old Dad wont let you have a leak down tester, at least pressurise it and spray some soapy water around.

You can check the crank seals by immersing the gearbox vent tube in a container of water.

I implore you to do some kind of leak test before it bites you.