My Rapide has a felt seal positioned in-between the crankcase and the oil slinger behind the dynamo pulley. It's about 75mm diameter and square section. It's quite loose, just held in by the casting flange where the dynamo shaft comes through to the primary case and the slinger. I understand that this isn't a standard part, but has anyone come across this before? I can't decide whether it's a good idea or not - on the one hand it may help to keep oil in the case, on the other, it may soak up oil and then dribble it out.