in the 1950s using a monocoque hollow shell of sheet-steel pressings welded together, into which the engine and transmission were installed from underneath. The machine could be tipped onto its side, resting on the bolt-on footboards for mechanical access.

A monocoque framed scooter was produced by Yamaha from 1960-1962. Model MF-1 was powered by a 50 cc engine with a three-speed transmission and a fuel tank incorporated into the frame.