Could very well be that it needs to settle in. I tried to pull it, turn the dynamo gear some, refit it and tightened the strap little bit up before doing the nut up - it was little less rattly, but still. Should there be something between the dynamo body and the mag body, like a thin sheet of some insulation material or? There's the tiniest gap between the two before I tighten down the strap, maybe this is the cause of a misalignement and the noise?
Ariel W/NG '40 "Bitzer", Triumph Thruxton '04, IZH-49 '56, Tempo Standard 150 '54.