It was
Alan's experience that his air cooled Honda CF 230 severely overheated at 70 mph, into the 30 mph headwinds, sitting upright and comfortable. Even spraying water on the head at speed could not keep the engine head temps within safe range. And that was in 65 degree ambient air!
It is too difficult to get the incoming air routed around the front wheel and fender to the engine.
I strongly suggest that you don't waste your efforts on an air cooled motor. A radiator is much easier to feed with cooling air.
Craig