Interesting comment about the valve cover gaskets. My Kohler now has a set installed as I made a set from Fel-Pro gasket sheet. The Kawasaki on the tank has valve cover gaskets from the factory. Maybe the later ones don't.
Don't quite follow the oil puff thing as the rings aren't submerged in oil when the motor is shut down, the oil is in the sump area not laying on the rings which only receive oil when the motor is running, I presume from splash as I've never had it apart to find out. I realize they both have a pressurized oiling system but I've assumed it was mostly for the valve train. Neither one of them hold much oil. Like I said, if either puked, the replacement would be a Pred engine. I stay up on valve adjustments and oil and filter changes. I was kind of surprised by the amount of oil sludge sitting in the valve covers on the Kohler when I removed them this spring to set the overheads. I use Rotella straight weight in both of them and the oil and filters get changed every spring. Never saw a sludge issue before with my other engines. Wasn't a lot but it was still there. I'm tempted to add a little Nano-Borate to the oil. That stuff keeps my diesels squeaky clean underneath the valve covers. Even my Kubota mechanic remarked this time, how clean the overhead was on the M I just had in the shop for a valve adjustment and injector spray test. Over 1600 hours and just like factory inside and I never get the bronze coloration inside that multi grade lubricants like to impart on valve train components. My other one with over 6500 hours on it is the same deal. Perfectly clean under the valve cover and nothing on the inside of the valve cover either.