The Model 1, more commonly known as Big 4, was a

Norton Norton may refer to: Places Norton, meaning 'north settlement' in Old English, is a common place name. Places named Norton include: Canada *Rural Municipality of Norton No. 69, Saskatchewan *Norton Parish, New Brunswick **Norton, New Brunswick, a ...

motorcycle A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...

made between 1907 and 1954 in various forms. With , it was the largest and most powerful side-valve engine in the model range and with plenty of low end torque was mostly used to haul sidecars. It was called Big 4 because it was rated at 4

tax horsepower The tax horsepower or taxable horsepower was an early system by which taxation rates for automobiles were reckoned in some European countries such as Britain, Belgium, Germany, France and Italy; some US states like Illinois charged license plate pu ...

. Mechanically, 'the power output, about which Norton Motors tended to be cagey, was lowly, 14

bhp BHP Group Limited (formerly known as BHP Billiton) is an Australian multinational mining, metals, natural gas petroleum public company that is headquartered in Melbourne, Victoria, Australia. The Broken Hill Proprietary Company was founded ...

for 1951'. Approximately 4700 of the nearly 100,000 military bikes made by Norton during WW2 were Big 4 sidecar outfits. Designed to carry two or three men plus their fighting equipment over very rough terrain, the Big 4 was used for reconnaissance and carrying loads of ammunition to the front line troops.

Civilian Norton Big 4

The first Big 4 machines were civilian versions starting in 1907 with a bore and stroke of 82 x 120 mm. The model was produced for nine years after the end of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. In 1948 the stroke was reduced to 113 mm to give 596cc capacity. In 1955 Norton ended the manufacture of side-valve singles to concentrate on overhead-valve twins.

Military Norton WD Big 4

The WD Big 4 was a development of pre-war trials outfit with a sidecar wheel coupled to the motorcycle rear wheel through a dog clutch and drive shaft. Initial trials were carried out at

Studland Studland is a village and civil parish on the Isle of Purbeck in Dorset, England. The village is located about north of the town of Swanage, over a steep chalk ridge, and south of the South East Dorset conurbation at Sandbanks, from which it is ...

Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...

and it coped well with challenging terrain. The simple design also meant it was easy to maintain in the field. All three 18" X 4.00 wheels were interchangeable with various makes of tyres for off road use. The sidecar was unarmoured, with thin sheetmetal on the front of the sidecar and there was no suspension in the rear of the heavy duty frame. The sidecar was mounted on four leaf springs, and had two

friction disc shock absorber Friction disk shock absorbers or André Hartford dampers were an early form of shock absorber or damper used for car suspension. They were commonly used in the 1930s but were considered obsolete post-war. Origins The friction disk pattern was in ...

s at the back. The Big Four was eventually replaced by the Ford GP or the

Willys Jeep The Willys MB and the Ford GPW, both formally called the U.S. Army Truck, -ton, 4×4, Command Reconnaissance, commonly known as the Willys Jeep, Jeep, or jeep, and sometimes referred to by its supply catalogue designation G503,According to i ...

in 1941. The Big 4 could be equipped with a

Bren gun The Bren gun was a series of light machine guns (LMG) made by Britain in the 1930s and used in various roles until 1992. While best known for its role as the British and Commonwealth forces' primary infantry LMG in World War II, it was also use ...

or a 3 inch mortar, bombs could be fitted to a platform in place of a sidecar, but this seems to have been a one off model, same with the Thompson equipped Big 4.

References

External links

Norton Big Four restoration
{{Norton motorcycles Military motorcycles Norton motorcycles, Big 4

Civilian Norton Big 4

Military Norton WD Big 4

See also

References

External links