The Norton Commando Production Racer was a hand built production racer produced by
Norton-Villiers
Norton-Villiers was a British motorcycle manufacturer formed in the 1960s following the collapse of Associated Motorcycles, AMC. During the general decline of the British motorcycle industry, a British Government initiative combined it with the ...
from 1970 - 1972. It was based on the road-going
Norton Commando
The Norton Commando is a British Norton-Villiers motorcycle with an overhead valve engine, OHV Pre-unit construction, pre-unit Straight-twin engine, parallel-twin engine, produced by the Norton Motorcycle company from 1967 until 1977. Initiall ...
, and although fitted with lights it was never intended as a road bike. The model was commonly known as the ''Yellow Peril''.
The exact number of PR machines produced is unknown, but estimates range from 119 to nearly 200.
Background
The origins of the Norton Commando can be traced back to the late 1940s when the Norton Model 7 Twin was designed by
Bert Hopwood
Herbert Hopwood (1908 – 17 October 1996) was a British motorcycle designer. He designed motorcycles for Ariel, Norton, BSA and Triumph.
Motorcycle design career
Hopwood left school at an early age to work for Ariel under designer Val Pa ...
. The twin-cylinder design evolved into 600 cc, then the 650 cc ''Manxman'' and Dominator until superseded by 750 cc
Atlas
An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets.
Atlases have traditio ...
before being launched as the 750 cc Commando in 1967.
The revolutionary part of the Commando, compared to earlier Norton models, was the award-winning
frame
A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent.
Frame and FRAME may also refer to:
Physical objects
In building construction
*Framing (con ...
developed by a team led by former
Rolls-Royce
Rolls-Royce (always hyphenated) may refer to:
* Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct
Automobiles
* Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...
engineer Dr. Stefan Bauer designed around a single top tube. The team to free the Commando from classic twin vibration problems and Bauer, 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.
From its 1967 beginnings the Commando took part in racing events. After successes in 1969 by dealer-entered machines like Paul Smart's second and Mick Andrews' 4th places in the
Isle of Man TT
The Isle of Man TT or Tourist Trophy races are an annual motorcycle racing event run on the Isle of Man in May and June of most years since its inaugural race in 1907 Isle of Man TT, 1907. The event begins on the UK Spring Bank Holiday at the e ...
Production class and a win in the Hutchinson 100 Production Class by Mick Andrew on the
Gus Kuhn
Gustave Emil Kuhn (17 October 1898 – 30 August 1966) was a successful British TT and motorcycle speedway rider during the 1920s and 1930s. He earned four international caps for the England national speedway team and served in the Royal Na ...
entered Commando and 4th by Peter Williams' Arter Bros machine, the company decided to produce a production racing model, hence developed the Production Racer model.
Technical
The PR was built at the ''Norton Villiers Performance Centre'' at the
Thruxton Circuit
The Thruxton Circuit is a motor-racing circuit located near the village of Thruxton, Hampshire, Thruxton in Hampshire, England, United Kingdom, about north of Southampton.
It has hosted motorsport events including the British Touring Car Ch ...
from 1970 - 1972, mostly by former
AJS
A. J. Stevens & Co. Ltd was a British automobile and motorcycle manufacturer in operation from 1909 to 1931. The company was founded by Joe Stevens in Wolverhampton, England. After the firm was sold, the name continued to be used by Matchless, ...
rider and senior development engineer Peter Inchley. Two different variants of the PR were built:
The first variant was based on the 1969 Commando R model produced at the
Plumstead
Plumstead is an area in southeast London, within the Royal Borough of Greenwich, England. It is located east of Woolwich.
History
Plumstead has been settled since ancient times, and London's earliest timber structure has been found here. ...
, London factory. The Plumstead models had a twin-leading-shoe front drum brake and the "cigar" silencers that were carried over from the
Atlas
An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets.
Atlases have traditio ...
. The oil tank was exposed and painted grey. On the Plumstead models the points were located in a housing behind the timing case where the magneto had been mounted on the Atlas models. The rev-counter drive was taken from the front of the timing cover.
The second variant was based on the 1971 Commando Roadster. After production has moved from Plumstead to
Wolverhampton
Wolverhampton ( ) is a city and metropolitan borough in the West Midlands (county), West Midlands of England. Located around 12 miles (20 km) north of Birmingham, it forms the northwestern part of the West Midlands conurbation, with the towns of ...
, changes were made to the Commando. The points were moved to the front of the timing cover and the rev-counter drive moved to the centre of the engine. A
disc brake
A disc brake is a type of brake that uses the #Calipers, calipers to squeeze pairs of #Brake pads, pads against a disc (sometimes called a
rake
Rake may refer to:
Common meanings
* Rake (tool), a horticultural implement, a long-handled tool with tines
* Rake (stock character), a man habituated to immoral conduct
* Rake (poker), the commission taken by the house when hosting a poker game
...
rotor) to create friction. There are two basic types of brake pad friction mechanisms: abrasive f ...
was fitted at the front and upswept "peashooter" silencers fitted. A cover was fitted over the oil tank.
Engine and transmission
The engines were carefully hand assembled and blueprinted.
Cylinder head
In a piston engine, the cylinder head sits above the cylinders, forming the roof of the combustion chamber. In sidevalve engines the head is a simple plate of metal containing the spark plugs and possibly heat dissipation fins. In more modern ...
s were individually chosen from stock castings and gas-flowed and squish bands machined into the combustion chambers. Larger inlet valves were fitted in phosphor-bronze valve guides and rockers polished. A 3S racing camshaft and shorter pushrods were used. Conrods were selected matching weights and high compression pistons fitted. Carburettors were stock size 32 mm
Amal Concentric
AMAL was a British engineering company servicing the motorcycle and other light-engineering motor industries between 1927 and 1993Amal GP carbs could be fitted as an option. Boyer-Bransden electronic ignition could be fitted as an option. Power output was - @ 7,000 rpm .
The standard Commando diaphragm clutch was retained, driving a close ratio 4 speed gearbox. A 5 speed Quaife gearbox was available as an option.
Chassis
The frame was selected from production frames and checked for exact dimensions and trueness. Brackets for the fairing were welded and the brackets for the stands were removed. Custom yokes were fitted that adjusted the steering head angle. The forks were re-valved and fitted with shorter progressive springs. Early variants had the twin leading shoe front brake fitted with racing linings. This could be replaced with a single disc brake if required, which required new fork legs with lugs for the Lockheed calliper. Later variants used the disk front brake introduced to the production bikes in 1971. Testing had shown that a narrower front wheel improved lap times, and an alloy WM2 rim with a 360 x 19 tyre was fitted. Rear rim was an alloy WM3 item fitted to the standard hub. The standard rear brake with ventilation holes drilled in it was used.
A alloy tank, a racing seat and a bikini fairing, all sprayed yellow, were fitted.
Racing results
One of the first victories for the bike was at the 1970
Thruxton 500 The Thruxton 500 was a motorcycle endurance race for production based road machines, covering 500 miles and ridden by a team of two riders per machine. The first event was a 9-hour race which took place in 1955, organized by the Southampton and Dist ...
with riders Charlie Sanby and Peter Williams. At that year's Isle of Man 750 Production TT, Williams came close to winning but ran out of petrol with sight of the finish line whilst leading. One of the first bikes was brought by an Italian team and on it their rider, Giuliano Ermanno, won the 1970 ''100 Miglia di Imola''.
At the
1971 Isle of Man TT
The 1971 Isle of Man TT was a motorcycle event held on 12 June 1971, on the 37-mile Snaefell Mountain course on the Isle of Man between Great Britain and Ireland. It was the third round of the F.I.M. 1971 Grand Prix motorcycle racing season (now ...
, Williams was third in the Formula 1 750 cc TT and set a new lap record of over 101mph in the 750 Production TT before retiring.