AJS Model D
Encyclopedia
The AJS Model D is a British motorcycle
made by A. J. Stevens & Co. Ltd
in Wolverhampton
between 1912 and 1925. With production halted by the First World War AJS managed to develop the Model D into a popular sidecar machine and it was eventually replaced by the larger capacity AJS Model E.
motorcycle powered by a JA Prestwich Industries Ltd
motor, with leading-link front forks and a swinging fork at the rear. A new company, A J Stevens & Co (AJS
), was founded in 1909 to manufacture motorcycles and at the 1912 London Motorcycle show they launched the 698cc side valve AJS Model D. Featuring cylinders at 50 degrees and chain drive to a three speed countershaft gearbox with a hand gear change, the original engines had quickly removable cylinder heads but after problems with oil leaks a more permanent head was specified for 1913. The side valve engine was lubricated by a 'total loss' system operated by a hand pump. Ignition was achieved with a Splitdorf Magneto and the fuel system featured an Amac automatic carburettor. The silencer was made from cast aluminium and the frame was a tubular 'diamond' construction, with Brampton bi-flex front forks, which had an unusual two way movement, and quickly detachable wheels. The sidecar version of the Model D proved particularly successful and became so popular that AJS were not able to meet demand.
After the war ended in November 1918 and the Ministry restrictions were lifted, AJS restarted motorcycle production at a new factory at Graisley Hill in Wolverhampton
and the Model D was resurrected with the capacity increased to 748cc and a new design of saddle and fuel tank. The idea of detachable cylinder heads was reintroduced with a cross strap and tie bolts to help ensure that they remained oil tight. At the Graisley Hill works AJS had their own foundry, enamelling facility, frame works and press as well as the motorcycle production line. Except for a few electrical and rubber components, the whole of the Model D was made in-house and the company also supplied engines to Brough Superior
, OK Supreme
and the Morgan Motor Company
.
An updated 7 hp version of the Model D was launched at the Olympia Motorcycle Show in November 1920. In 1923 a cheaper version called the Model D1 was introduced and 1924 was the best year for sales, which continued to outstrip the capacity of the factory despite increasing the Graiseley Hill works to 230,000 square feet.
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 A. J. Stevens & Co. Ltd
AJS
AJS was the name used for cars and motorcycles made by the Wolverhampton, England, company A. J. Stevens & Co. Ltd, from 1909 to 1931, by then holding 117 motorcycle world records, and after the firm was sold the name continued to be used by Matchless, Associated Motorcycles and Norton-Villiers on...
in Wolverhampton
Wolverhampton
Wolverhampton is a city and metropolitan borough in the West Midlands, England. For Eurostat purposes Walsall and Wolverhampton is a NUTS 3 region and is one of five boroughs or unitary districts that comprise the "West Midlands" NUTS 2 region...
between 1912 and 1925. With production halted by the First World War AJS managed to develop the Model D into a popular sidecar machine and it was eventually replaced by the larger capacity AJS Model E.
Development
In 1905 the Stevens Motor Manufacturing Company built a V-twinV-twin
A V-twin engine is a two-cylinder internal combustion engine where the cylinders are arranged in a V configuration.- Crankshaft configuration :Most V-twin engines have a single crankpin, which is shared by both connecting rods...
motorcycle powered by a JA Prestwich Industries Ltd
JA Prestwich Industries Ltd
JA Prestwich Industries, was an English engineering company named after founder John Alfred Prestwich, which produced cinematographic equipment, internal combustion engines , and other examples of precision engineering.-History:J. A...
motor, with leading-link front forks and a swinging fork at the rear. A new company, A J Stevens & Co (AJS
AJS
AJS was the name used for cars and motorcycles made by the Wolverhampton, England, company A. J. Stevens & Co. Ltd, from 1909 to 1931, by then holding 117 motorcycle world records, and after the firm was sold the name continued to be used by Matchless, Associated Motorcycles and Norton-Villiers on...
), was founded in 1909 to manufacture motorcycles and at the 1912 London Motorcycle show they launched the 698cc side valve AJS Model D. Featuring cylinders at 50 degrees and chain drive to a three speed countershaft gearbox with a hand gear change, the original engines had quickly removable cylinder heads but after problems with oil leaks a more permanent head was specified for 1913. The side valve engine was lubricated by a 'total loss' system operated by a hand pump. Ignition was achieved with a Splitdorf Magneto and the fuel system featured an Amac automatic carburettor. The silencer was made from cast aluminium and the frame was a tubular 'diamond' construction, with Brampton bi-flex front forks, which had an unusual two way movement, and quickly detachable wheels. The sidecar version of the Model D proved particularly successful and became so popular that AJS were not able to meet demand.
First World war
The outbreak of the First World War in 1914 nearly saw the end of the company as a motorcycle producer as they failed to secure motorcycle contracts for the armed forces and the factory was turned over to produce munitions for the war effort instead. In 1916 the Ministry of Munitions banned production of motorcycles except for military use, but in 1917 they needed to fulfil an order from Russia for large numbers of motorcycles and AJS were contracted to build 1100 6 hp military motorcycles, enabling them to continue development of the Model D despite the restrictions.Post War resurgence
Wolverhampton
Wolverhampton is a city and metropolitan borough in the West Midlands, England. For Eurostat purposes Walsall and Wolverhampton is a NUTS 3 region and is one of five boroughs or unitary districts that comprise the "West Midlands" NUTS 2 region...
and the Model D was resurrected with the capacity increased to 748cc and a new design of saddle and fuel tank. The idea of detachable cylinder heads was reintroduced with a cross strap and tie bolts to help ensure that they remained oil tight. At the Graisley Hill works AJS had their own foundry, enamelling facility, frame works and press as well as the motorcycle production line. Except for a few electrical and rubber components, the whole of the Model D was made in-house and the company also supplied engines to Brough Superior
Brough Superior
Brough Superior motorcycles, sidecars, and motor cars were made by George Brough in his Brough Superior works on Haydn Road in Nottingham, England, from 1919 to 1940. They were dubbed the "Rolls-Royce of Motorcycles" by H. D. Teague of The Motor Cycle newspaper. Approximately 3,048 of 19 models...
, OK Supreme
OK-Supreme
OK-Supreme was a British motorcycle manufacturer from 1899 to 1939 located in Birmingham. Grass-track racing versions of the machines continued to be available until 1946.-History:...
and the Morgan Motor Company
Morgan Motor Company
The Morgan Motor Company is a British motor car manufacturer. The company was founded in 1910 by Harry Frederick Stanley Morgan, generally known as "HFS" and was run by him until he died, aged 77, in 1959. Peter Morgan, son of H.F.S., ran the company until a few years before his death in 2003...
.
An updated 7 hp version of the Model D was launched at the Olympia Motorcycle Show in November 1920. In 1923 a cheaper version called the Model D1 was introduced and 1924 was the best year for sales, which continued to outstrip the capacity of the factory despite increasing the Graiseley Hill works to 230,000 square feet.