If the noise is a clicking at each revolution, it could be as simple as a small diameter valve stem passing through a slightly larger hole in the rim. At each revolution, the slight flexing of the tire causes the valve stem to move back and forth in the rim just enough to make an audible clicking noise. I solved it on my old Corimas by cutting a small piece of a foam sleeve that the local stationery shop sells as pencil/pen grips and putting it around the stem and wedged into the rim.