Spacesailor, there was bloke designed such a system for light aircraft engines, but I cant remember his name ill post if I find it.
the idea had more to do with cooling the undersides of the cylinders more as that was the hot spot nearest the exhaustson his chosen engine, the only downside i remember was the potential for a screen covered in oil if you had a leak.
Skippy I've never measure the temp in my engine bay, are you measuring this in the cruise?
p.s. 25c above ambient doesnt seem at all worrying to me, but like I' said earlier, not something I've investigated in the Rotax installs I've had.