Leaking rear main seal

[ERA Chas]

Usually wet threads are a sign of the stem seals going or gone - so is the resultant blue exhaust smoke. Teflon hardens in street use and lets oil into the chamber. You want Viton seals. When not burning off, oil will migrate down the stem when cold, coat the chamber walls and soak the plug threads. A curled-up intake gasket can let oil into the port, and drip past an open valve into the chamber too.
Also, a leak-down test will show if the air if coming out the top (seals or valve seats) or bottom (rings).