Now I'm no expert on air cooled engines

But isn't it normal practice to have the air cooled bit sticking out in the airflow?

All seems to be set up there so the engine gets the absolute minimum airflow over the cooling vanes and retains as much heat as possible.

As a matter of fact, if I deliberately set out to position an air cooled engine in a frame so as to ensure the greatest chance of it overheating, I don't think I'd have done anything different.