Norton Isolastic frame
The isolastic frame was Norton Motorcycle Company system of using rubber bushings to isolate vibration from the engine to the frame. In September 1967 the Featherbed frame was replaced by the isolastic frame Norton for use in the Commando.[contradiction]
In an attempt to reduce the problem of engine vibration being transmitted through the frame, as the capacity of the motorcycle engines increased to 750cc with the Norton Atlas, Norton decided to look at changes to the Featherbed frame and the 1969 Norton Commando was the result.[contradiction] The innovative isolastic frame derived from the Featherbed made it much smoother through the use of rubber bushings to isolate the engine and swingarm from the frame, forks, and rider. As the rubber bushings wore, however, the bike became prone to fishtailing in high-speed turns. Earlier models therefore required careful adjustment of the clearance between frame and mounts using shims.