Topic: oil leaks from the exhaust outlet

[kayE]

i need some help regarding the 350f . i want to ask u some question.i am from malaysia and its very rare here to own cb's.
after rebuilding my engine, there's some black oil out from the exhaust outlet ( which is out from the cylinder head) and its make some white smoke too..in your opinion what is my 350f problems ? (sorry my language is worse a bit).
do i need a new set of pistons?

[bjbuchanan]

Did you put some type of non hardening sealant on the rubber pucks/discs that were under your cam towers? Could seem like an oil exhaust, was happening on my bike.

The leak is semi-internally and shows with wet fins near the exhaust ports