Cushman had a varidrive for a while along with their 2 speed manual shifter. Rear belt pulley was springloaded and the front was squeezed together by a centrifugal setup.
Some Eurobike, Husky I think, made a self shifting 4 speed that used a complicated set of centrifugal and over-running clutches for the local military.
Honda made an automatic 750 for a little while, but it didn't seem to be very popular.
I remember hearing that NSU was either making or working on a bike with a scaled down version of the Saxomatic transmission used by VW and Renault. This was a manual shifter with an electric automatic clutch.
