Replacing the 250cc two-strokes of the old Lightweight class, Supertwins combine creativity with a huge amount of speed. James Hillier holds the current lap record, set in 2015 at a speed of 120.848mph. Supertwins are basically 650cc commuter twins with higher-end suspension. The frame can’t be modified but you can replace the swingarm – many Kawasaki runners use the lighter ally swingarm from a Versys 650. Capacity must stay the same, but you can replace pistons, cams, tune the cylinder head, lighten the internals and fit a quickshifter and slipper clutch.
Power 90bhp Weight 140kg Top Speed 160mph Cost to build £20k