John Player Norton, a Monocoque Masterpiece
Drawing on lessons learned during 1972, the John Player Norton team wheeled out a radical racer for the next session. Conceived by engineer-rider Peter Williams and crafted by JPN technicians, the 1973 John Player Norton ranks as one of the cleverest designs in road racing history.
Instead of a tubular frame, it has a monocoque chassis fabricated in stainless steel sheet, carrying the engine and gearbox on Isolastic mounts. As well as providing a rigid structure, the monocoque incorporates low-slung fuel tanks, engine cooling ducts and mounts for sleek fairings. William's aim was to compensate for the Norton engine's limited power output by creating a machine with excellent handling and superior aerodynamics.
Cast magnesium alloy wheels, still a novelty in 1973, are fitted along with disc brakes at both front and rear. A one-piece moulding forms a top cover for the engine, the seat and the tailpiece containing the battery and other ignition components.
The sleek and low Norton suited William's flat-on-the-tank riding style. His 1973 successes included being Britain's best performer in the 1973 Anglo-American series, joint top point scorer with Suzuki's Barry Sheene in the British Super Bike Championship and breaking the motorcycle lap record at Silverstone.
Best of all for Norton, Williams won the 1973 Formula 750cc TT, setting the second fastest-ever lap of the mountain course at 107.27mph and giving the marquee its first Isle of Man victory for 12 years. Mick Grant finished second on a similar machine. Dave Croxford, permanent JPN team-mate to Williams, won the 1973 705cc ACU British championship on a monocoque.
(Source National Motorcycle Museum)