Well i have one of these engines installed to a power washer it has electric start and runs very smooth it only has about 2 hours on it, i needed a spark plug for a lawnmower and i had no choice but to take it out of the 160 clone anyway i took it out and it was black and slightly wet with oil. I then took a flashlight and looked in to the cylinder and the top of the piston had a very light coating of oil. Now the engine does not release smoke when running, and i don't think i this coming from the valves as they both have valve seals which are in good condition or anything but it does make a slight metallic knocking or pinging sound when the engine is at warm idle to 2000rpm i don't think it is detonating or anything though. back to the oil is it because the engine is new and the rings haven't seated correctly ?