Engine oil cooler

Dennis,
I don't think a blanket statement that air cooleds run hotter is valid. Most air cooleds have no t/stat and are quite inefficient when running lightly loaded because they're not running hot enough!! You'll probably find that gov'ts wanted emissions lower on bikes plus the mfg, at the same time, could combine a much more efficient eng w/ temp being stabilized under all load conditions. Good quality air cooleds have t/stats. Oil needs to be at least 230F or more. I think you'll find that the frequent oil changes in most Kohlers & Onans is due to unburned fuel getting by rings and valves due to mixtures necessary to cover the wide operating temps they endure plus very poor combustion chamber shapes not much better than 100 yrs ago. DCD

Dennis,
Those examples in post 1567 corroborate my post654. These toy engines we have are built w/o regard for the extremes. One type fits all, well almost.When an eng gets hot enough the fuel will preignite. The shock will make the rings lose contact with cyl walls and the fuel goes into crankcase past rings, diluting oil. But you know that, thought some others would be interested. DCD