Right, the reason for the question is that the fins on those oil cans are shallow rather than deep like the fins on the heads and jugs on an air cooled bike. Any way I have an idea that could be interesting and may actually work. The idea is to take an old cylinder jug and make an oil tank slash cooler out of it.

I have no faith in human perfectability. I think that human exertion will have no appreciable effect upon humanity. Man is now only more active - not more happy - nor more wise, than he was 6000 years ago. Edgar Allan Poe