Hello everyboddy,I am new on the forum,I came here by a link,from a french forum,so sorry for my poor english,but I hope I can be anderstood!!!If its not the case,let me know
In my opinion,about that foam ander the alternator cover,
is that to put this sort of foam(polyurethan)is the worth thing to do,(from the manufacturer)because,first af all,it is waterproof,I mean if their is some water traped ander it,it can not be evacuate by capilaryty effect,so even a small amont will stay here for a verry long time.
When riding,we produce heat,which ,in combination whith water,and maybe salt,is the best to help corrosion to do his job!
I dont know exactly the purpuse of that foam,but for me , It makes sens that it must be removed asap,so the fresh air can flow arond,keep it dry.In the oldest bikes(my last one was a R1150R),I never noticed any insulation like this.Accoustic?like in cars?I dont know,anyway,things who goes well dont need to be improved...sometime you want to do better,but the effect is the opposit!
So in conclusion,I would say,to prevent corrosion in this spot,the best is to take off that foam,once it is removed,the water cant stay here,so no need of wax,maybe just a thin film WD 40,that's it!