The CS1 was only about for a short time, but it paved a new route for Norton and is therefore considered to be an important and pioneering model in the Norton family. This is a short article about the life of an exhilarating and throaty machine that could be considered to be one of the most purposeful looking vintage motorcycles out there.
In order to understand where the CS1 came from, we need to rewind a few years from its birth, and to the overhead valve (OHV) Norton’s. The OHV bikes arrived in prototype form in 1922, and very quickly established a reputation for speed and reliability. The OHV Norton collected many coveted trophies across the continent, with wins in the Isle of Man Senior TT and at the French and Belgian GPs. As the decade rolled on, however, manufacturers continued to seek out the optimum engine setup that would keep them ahead of the game… cue the camshaft.
A CS1 chilling in the snow. Credit: Olivier Purtschert.
The overhead camshaft (OHC) configuration really became prominent in motorcycle racing in 1926 when a 350cc OHC Velocette won the Junior Isle of Man TT. The achievement caused somewhat of a stir in the TT camp, and manufacturers took note, including Norton.
A Norton CS1 in race trim. Credit: Jochen Schell.
The Norton Cam Shaft 1 (CS1) was the test bed for Norton in its jump into the “cammy” world. The engine was designed by Walter Moore, and it shared the same bore and stroke dimensions as its older OHV brother (79mm x 100mm). The motor featured two pairs of bevel gears and a shaft to create a direct drive to the overhead-cams which were on a single camshaft. The upper, non-camshaft bevel carried the weight of the drive-shaft, while the separate cams actuated two-piece rockers that extended out of the cam-box to work the semi-exposed valves. It was a complex design, but it provided that little extra poke!
A close up of the top end of a CS1. Credit: Jochen Schell.
In 1927 the CS1 was ready for trial. Norton fielded a solid and powerful entry in the Senior TT, with Stanley Woods, Alec Bennett and Joe Craig all armed with the brand new overhead-camshaft Norton. Woods was the favourite (he won the Senior in 1926 with Norton); he initially led the race, establishing a new lap record of 70.90 mph, but then slowed with a blown clutch, allowing Bennett to move ahead, overtake Jimmy Guthrie on the New Hudson, and win the race.
The success of the CS1 in the TT set a precedent for Norton moving forwards, and in November the same year, the public were able to purchase a production version which was unveiled at the Earls Court Motor Show. It featured a new cradle frame (instead of the diamond frame used with the previous Norton pushrod engine) and Webb front forks, as featured on the TT race bike; these modifications offered a huge improvement to stability under riding conditions.
A nicely ‘patinated’ CS1 with foot change at the 2024 Brooklands 100.
A three-speed Sturmey Archer gearbox was fitted to the CS1, with the long change lever laid flat so that it could be operated by foot. This was quite an unusual modification, as most bikes of this era featured a tank-mounted hand-change configuration. The bike could be supplied with a touring gearbox, or a close ratio gearbox, solo or sidecar gear ratios, and had the option of a kick start. The generous, oversized drum brakes were reputedly copied from those of the Ford Model T, but very much needed to deal with the pace of the machine.
The CS1 was an impressive bike, and it soon acquired the nickname the Cricket Bat – so called because the vertical shaft and lower timing case resembles the willow of the batsman.
In 1928 Norton added another weapon to their arsenal. It was a mini version of the CS1, a 350cc camshaft, which was entered into the Junior TT, albeit without success. The snappy bike went on sale to the public in 1929 as the Camshaft Junior, but never really caught on – most likely as a result of the Depression, coupled with the fact that there were cheaper 350cc alternatives already on the market.
A 1929 CS1, bursting with character. Credit: Mikey Alcock.
In 1929 there was a clashing of heads, and Norton were at the hands of a bit of a mix-up to personnel. Walter Moore left the company and was replaced by Joe Craig who became famous as the firm’s race director. There was mixed success in competition – nothing to write home about – the CS1 was an impressive machine, however the next couple of race seasons were futile, and Norton needed a rethink.
The rethink was handed over to the combined talents of Craig and Arthur Carroll who pulled apart the CS1 and returned to Norton with something quite special. In fact, very little of the Cricket Bat engine was retained… of note, the cricket bat silhouette that had characterised the machine to date was gone.
It took a year-or-so for the Craig-Carroll engine to bed in, and in 1931 Norton swept all before them at the Isle of Man TT, finishing 1st (Tim Hunt), 2nd (Jimmy Guthrie), & 3rd (Stanley Woods) in the Senior, and 1st (Tim Hunt) and 2nd (Jimmy Guthrie) in the Junior. This was the start of a golden era for the company as they went on to dominate road racing for several years, both at home and on the Continent.
The Carrol engine became the basis for all of their future OHC and DOHC machines, in particular the International, and further down the line, the post-war period Manx Norton’s. The CS1 at this point in its life could be described as a touring version of the International, and it remained in production until the onset of war in 1939.
A 1930 CS1. Credit: Stuart Woods – note the change in engine design.
The CS1 changed the game for Norton and played a pivotal role in the development of their bikes over the years. It is a landmark sports model and is regarded by enthusiasts in the vintage world as one of the most desirable Norton motorcycles.
an article by The Girder Club
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