Hello ladies and gents this is the Viking telling you that today we are talking about
NORTON COMMANDO
The Norton Commando was a British Norton-Villiers motorcycle with an OHV pre-unit parallel-twin engine, produced by the Norton Motorcycle company from 1967 until 1977. Initially having a nominal 750 cc displacement, actually 745 cc (45.5 cu in), in 1973 it became an 850 cc, actually 828 cc (50.5 cu in). It had a hemi-type head, similar to all OHV Norton engines since the early 1920s.
During its ten years of production, the Commando was popular all over the world. In the United Kingdom it won the Motor Cycle News "Machine of the Year" award for five successive years from 1968-1972. Given that its engine was an old pre-unit design, even Norton's chairman, Dennis Poore, expressed surprise at the Commando's remarkable success.
The origins of the Norton Commando can be traced back to the late 1940s when the 497 cc (30.3 cu in) Norton Model 7 Twin was designed by Bert Hopwood. The twin-cylinder design evolved into 600 cc, then the 650 cc Manxman and Dominator until superseded by 750 cc Atlas before being launched as the 750 cc Commando in 1967. As well as having a radical new frame, the Commando's engine (which was mounted vertically in earlier models) was tilted forward. This was relatively easy as the engine was "pre-unit", that is, the gearbox was not integral with the crankcase, and the change gave three benefits: (i) the centre of gravity was moved further forward; (ii) this allowed more space behind the carburettors for the airbox; and (iii) it gave an attractive raked appearance to the motorcycle.
Isolastic system
The revolutionary part of the Commando, compared to earlier Norton models, was the award-winning frame developed by former Rolls-Royce engineer Dr. Stefan Bauer.[5] He believed the classic Norton Featherbed frame design went against all engineering principles, so Bauer designed his frame around a single 2.25 in (57 mm) top tube. Bauer tried to free the Commando from classic twin vibration problems, which had severely increased as the volume of the basic engine design expanded from the 500 cc of Edward Turner's 1938 Triumph Speed Twin. He, with Norton-Villiers Chief Engineer Bernard Hooper and assistant Bob Trigg, decided that the engine, gearbox and swing-arm assembly were to be bolted together and isolated from the frame by special rubber mountings.
This eliminated the extreme vibration problems that were apparent in other models in the range, as it effectively separated the rider from the engine. Named the Isolastic anti-vibration system, the system's patent document listed Hooper as the lead inventor. Although the Isolastic system did reduce vibration, maintaining the required free play in the engine mountings at the correct level was crucial to its success. Too little play brought the vibration back; too much, and the result was "very poor" handling.
I hope you liked this post and as always have a chilled day from the Viking.
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