Rob,
My exhaust is quite oily, I guess they always will be as oil in mixed with the fuel so it’s unlikly that it will be completely burnt off, however the exhaust fumes aren’t to smokey only when started so it’s running ok.
A previous owner has put a shield on top of the starter motor and solenoid to prevent any oil driving onto it, it has done a very good job.
My silencer really needs cleaned / decarbonised; to clean it the manual says that the it has to be burnt out and all the exhaust components made red hot in a forge or with a welding torch.