AJS Model 31
Encyclopedia
The AJS Model 31 was a British
motorcycle
made by Associated Motorcycles at the former Matchless
works in Plumstead
, London
. Developed in 1958 specifically to capture the potentially lucrative US market, the last Model 31 was produced in 1966.
by the same company. Designer by Phil Walker, AMC knew that it had to be a 650cc but wanted to use as many cycle parts from the Model 11 as possible. The cylinders could not be bored out further so the stroke was lengthened from 72.8mm to 79.3mm, resulting in a capacity of 646cc. The meant developing a new crankshaft and primary chaincase, which also provided the opportunity to add a Lucas alternator. Volume production began in September 1958.
development to address the problems and modify the bikes for racing - with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500
long distance endurance race on the AJS Model 31. Encouraged by this victory in 1963 the AJS Model 31 gained the name Hurricane).
By 1966 the company were in financial trouble and production ended.
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...
made by Associated Motorcycles at the former Matchless
Matchless
Matchless is one of the oldest marques of British motorcycles, manufactured in Plumstead, London, between 1899 and 1966. A wide range of models was produced under the Matchless name, ranging from small two-strokes to 750 cc four-stroke twins...
works in Plumstead
Plumstead
Plumstead is a district of south London, England, located in the London Borough of Greenwich. Plumstead is a multi cultural area with large Asian and Afro-Caribbean communities, in similarity to local areas such as Woolwich and Thamesmead...
, London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. Developed in 1958 specifically to capture the potentially lucrative US market, the last Model 31 was produced in 1966.
AJS Model 31
The AJS Model 31 was also produced as the Matchless G12Matchless G12
The Matchless G12 is a British motorcycle made by Associated Motorcycles at the former Matchless works in Plumstead, London. Developed in 1958 specifically to capture the potentially lucrative US market, the last G12 was produced in 1966.-Matchless G12:...
by the same company. Designer by Phil Walker, AMC knew that it had to be a 650cc but wanted to use as many cycle parts from the Model 11 as possible. The cylinders could not be bored out further so the stroke was lengthened from 72.8mm to 79.3mm, resulting in a capacity of 646cc. The meant developing a new crankshaft and primary chaincase, which also provided the opportunity to add a Lucas alternator. Volume production began in September 1958.
AJS Model 31 De Luxe
In 1959 the Model 31 was redesigned and modernised as the De Luxe with a new full cradle tubular duplex frame and a new cylinder head. Vibration had always been a problem, so the crankshaft was upgraded to nodular iron. Capable of 100 mph performance, the AJS Model 31 became popular with the American market.AJS Model 31 CSR
The AJS Model 31 CSR designation officially stood for Competition / Sport / Road but it was dubbed the Coffee Shop Racer by its rivals. With its distinctive 2 into 1 'siamese' exhaust system and upgraded camshafts the CSR was a high performance motorcycle but still prone to leaks and vibration. The factory diverted Chief Engineer Jack Williams from AJS 7RAJS 7R
The AJS 7R was a 350 cc racing motorcycle built from 1948 to 1963 by Associated Motor Cycles, also known as the ‘Boy Racer’, first won victories for the factory, and then went on to win races for privateers when made generally available from 1954....
development to address the problems and modify the bikes for racing - with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500
Thruxton 500
The Thruxton 500 is a 500 mile motorcycle endurance race held at Thruxton Circuit, near Andover in Hampshire, United Kingdom, which is the fastest racetrack in the country...
long distance endurance race on the AJS Model 31. Encouraged by this victory in 1963 the AJS Model 31 gained the name Hurricane).
By 1966 the company were in financial trouble and production ended.