The timing is set correctly, I think. The top end compression, that is, compression after the exhaust port has closed, is good. I don't have a compression tester, but it feels good. i have seen a crankcase compression tester before, but it was a wierd special part on ebay, and i don't have one. I did put on a new base gasket the first time i took it apart. Could the thinner gasket be preventing a good seal? I can't detect any compression leaks. This is very frustrating.