My rotor grenaded and I am in need of a left engine cover. Anyone know where I can get one? Doug in Athens, Alabama USA

You should be able to use one from a watercooled bike such as a 906, a 916, 996, 998, S4 etc. Air cooled 900s can also be adapted. The 916 onwards covers have a sliding seal assembly behind the water pump so make sure you have one of those to fit. The 906 type covers have individual seals and bearings and the housing is an interference rather than slide fit.

This is the great thing with these 900 engines,lots of commonality between bikes.

Check f alternator fitment issues when using covers from other models.

So how about a 916 left side cover? Better yet can i put a 916 engine in the 907?

You might ask suggestions to finnpaso... I suppose that rotors are not all the same and elder engines (Paso/elefant) have a smaller generator.
Otherwise, a 944 engine cover should fit.