The Model 1, or more commonly known as Big 4 was a Norton motorcycle made between 1907 and 1954 in various forms. With 633 cc (38.6 cu in), it was the largest and most powerful side valve engine, with plenty of low end torque in the model range, and was mostly used to haul sidecars. 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. It was called Big 4 due to its power rating of 4 hp, calculated as tax horsepower. Calculated using current methods the horsepower rating would be 14 brake horsepower.
This is a very nice Norton Big Four 600cc in very original condition. From a private collection, the Big Four shows 317 miles recorded. A lovely unmolested bike, and a great addition to any collection.