A look at the British Norton ‘Big 4’

In 1898 the British motorcycle designer and engineer James Lansdowne Norton established a motor manufacturing company bearing his name in Birmingham, which produced motorcycles using engines built in France by companies such as Peugeot. Nine years later and Norton began building a new machine of his own design known as the Model 1, but often referred to by the more familiar term of ‘Big 4’.

Initially these early machines were intended for the civilian market and fitted with a 3.5bhp petrol engine, but it was not long before the army began to show an interest in the machine. When WWI broke out the British army was using the Big 4 and these would see service in most theatres of war, being used for liaison roles and despatch rider duties delivering messages. The company of Norton continued to produce the Big 4 during the 1920 and 1930s, making successive improvements which included a slight power increase from 490cc to 500cc. In 1937 the army was still using the Big 4 and Norton would supply over 100,000 machines up to the end of the war in 1945, which included the solo WD16H. The motorcycles were supplied to overseas Commonwealth armies, including Australia which took delivery as early as 1939, and all military machines had the prefix term WD which denoted War Department.

The production figure also included some 4,700 WD Big 4 machines with a combination sidecar fitted with a driven wheel. This feature was achieved by connecting the sidecar wheel to the rear wheel of the motorcycle by means of a dog clutch to provide drive power. The combination could carry three men, the driver and pillion passenger with the third riding in the sidecar, along with their personal kit and weapons. Pre-war field trials were conducted along the Studland coastline in Dorset where the cross-country capability of the WD Big 4 was proven and it remained a popular machine with the troops using it.

The sidecar was fabricated from sheet steel and fitted with four leaf springs and two friction disc shock absorbers at the rear. It was sufficiently spacious to accommodate a fully equipped soldier passenger or carry supplies such as ammunition or food cross-country to the front line. The combination also gave mobility to Bren machine gun crews to move around the battlefield to provide fire support. An exercise was conducted to evaluate the possibility to carry a 3-inch mortar. Apart from its liaison and reconnaissance roles the machine could also serve in supporting the evacuation of wounded troops. The WD Big 4 could be configured to carry weapons which could be operated by the sidecar passenger and the driver of the machine. A bracket could be fitted horizontally running front to back on the sidecar which allowed a Bren machine to be mounted. A bracket could also be fitted to the handlebars which allowed a Thompson sub-machine gun to be mounted and held in position ready to be fired by the driver. These weapons were mainly for self-defence and the crew would still have been left vulnerable to returning fire from the enemy.

A trial was conducted to prove the WD Big 4 as being capable of carrying the British army’s 3-inch mortar. Fully assembled the mortar weighed over 115-pounds, complete with baseplate and bipod support, and measured around four feet in length. Such a cargo load should have been within the capabilities of the motorcycle, given that it could carry three soldiers. Ammunition was carried in canisters mounted on the platform fitted in place of the sidecar, either side of the mortar barrel. Presumably another WD Big 4 would have been accompanying to carry the crew to serve the mortar. The breech end of the barrel was fitted to a baseplate mounted on the floor of the side car which had been specially adapted for the firing role. However, the recoil force on firing would have been more than the WD Big 4 could withstand and in the end, nothing appears to have come from the trials and the idea was dropped.

The WD Big 4 was fitted with a 14hp air-cooled 633cc single-cylinder side-valve petrol engine, making it the largest and most powerful of its type giving road speeds up to 68mph. The machine weighed 305-pounds dry and the petrol tank had a capacity of 2.75 imperial gallons. Overall length was just over eight feet with a wheelbase of four-feet and 6.25-inches and a ground clearance of 4.5-inches. Height to the top of the saddle stood at two-feet and 3.5-inches with a width of two-feet and 6.5-inches over the handlebars.

During the war WD Big 4 was a popular machine with the troops, because of the engine torque, but later its role would be largely reduced with the introduction of the Willys Jeep. When the British Expeditionary Force (BEF) was sent to France in 1939 the Royal Northumberland Fusiliers serving as part of the 50th (Northumbrian) Division were equipped with Norton Big 4 combinations. The German army would later use those machines which had been captured at Dunkirk during the Battle for France in May and June 1940.

The WD Big 4 remained in production for civilian use until 1954, with its performance being improved through various models. Today it still remains popular with owners and there are various associations, including a Norton Owners Association with an International Branch, which includes US and Canadian owners, details of which can be found at: www.inoanorton.net 

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