ORIGINAL: fzxlvf
This engine is a 4-stroke and the leak I am referring to appears to be coming through the exhaust port valve, not through the exhausut manifold itself (via a leaky thread/seal where tape would help).
Firstly, unless OS has changed the engine mid production run, the rocker cover should be black and made of aluminium.
The engine comes from the factory with no seal or gasket on the rocker cover and they can leak in use. Many of us smear a little RTV sealant on the mating faces to seal this.
It is entirely possible - and in fact desirable - that oil is coming into the rocker box via the exhaust valve guide. My inverted Surpass .52 and .91's rocker boxes are usually full of oil when I've checked the tappets.
With a smear of sealant on the rocker cover and teflon or sealant on the exhaust threads, these engines are among the least messy glow engines available.