BODYWORK. Frame: tubular steel, single cradle. Front suspension: parallelogram fork. Rear suspension: rigid.

MECHANICS. Engine: single-cylinder, four-stroke. Displacement: 490 cc (79 x 100 mm). Transmission: chain drive. Gearbox: 3-speed. Engine no.: CS42768.

DOCUMENTS: No documentation.

HISTORY: The CS1 could be described as a touring version of the International. Its engine, featuring an overhead camshaft driven by a vertical shaft with bevel gears at each end, first appeared in 1927 powering the factory’s racing machines. The following year, it was fitted to a production chassis identical to that of the ES2.

The technical design was the work of Walter Moore, who held the patent. When Moore left Norton for NSU in 1929, the company commissioned Arthur Carroll to completely redesign the engine. From 1931 until the end of its production in 1939, the CS1 featured this new engine, making it the most sporting and fastest road-going model offered by the British manufacturer.

This particular example is well known, its owner often took part in veteran motorcycle meetings held in Catalonia, and despite having been restored many years ago, it remains in excellent condition.