I believe oil is the way to go.
As far as paper element filters, especially the small round ones so many use with the helmet style three inch air cleaners or the small traditional chrome air cleaners, I found that they will actually tend to restrict air flow through the carburetor(s), even when new and clean, to the point to where you are actually driving with with a situation equal to the choke being partially closed. This can effect gas mileage and the ever popular "gray" tailpipe color is never to be seen again. This is why some of our vendors are now showing the use of a larger air cleaner and a larger filter, if a paper element is to be used.
Joe
