Cotton, The Motorcycle Masterpiece ®
The triangulated frame
From around 1913, F. W. Cotton took part in motorcycle hill climbs and trials. Through this experience, he became very aware of the weaknesses of the traditional diamond frame, a design originally derived from pedal bicycles.
To overcome these limitations, Cotton developed and patented a triangulated frame. This innovative design became a defining feature of Cotton motorcycles and remained in use until the outbreak of the Second World War.
The frame used straight, narrow triangulated tubes running from both the top and bottom of the steering head to the rear wheel fork-end lugs. An alternative layout, where the tubes met at the seat post, was considered but does not appear to have been used on production motorcycles.
Additional multi-triangulated tubes connected the steering head, engine, seat post, and rear wheel fork ends. This construction provided a strong yet lightweight structure, greatly reduced frame flex, and allowed for a lower centre of gravity, improving stability and handling.
Front suspension was provided by sprung front forks, while rear comfort was achieved through a sprung seat, which effectively acted as rear suspension.
Cotton, The Motorcycle Masterpiece ®
2½ h.p. Blackburne-engined motorcycle
The Cotton motorcycle had already achieved notable success in trials competition and had won the Junior TT the previous year, confirming the practical value of its design.
For 1925, the combined chain-and-belt drive model was discontinued. The smallest Cotton model became a 2½ h.p. Blackburne-engined motorcycle, fitted with a three-speed gearbox, clutch, kickstarter, and chain final drive.
The sports model used a Blackburne sports engine capable of very high engine speeds, allowing a claimed top speed of 70 to 75 mph. On these models, the engine was mounted leaning forward, which lowered the centre of gravity and improved stability when cornering.
All models were displayed on the Cotton stand. Compared with the previous year’s machines, the 1925 models featured heavier mudguards, magneto shields, and silencers on the overhead-valve models. Less visible, but equally important, was the use of thicker material for the fuel tank, improving strength and durability.
Historical Context 1923–1925
During these years Cotton’s identity became firmly established around:
- The patented triangulated frame
- Proprietary engines (Villiers and Blackburne)
- Isle of Man TT competition success
- A focus on sporting road machines rather than mass-market transport
Cotton, The Motorcycle Masterpiece ®
By 1923, Cotton had firmly established its reputation through Isle of Man TT success. The triangulated frame was now fully associated with competitive performance.
Models 1 through 11, with Blackburne and Villiers engines.
Model 1
Lightweight Cotton fitted with a Villiers single-cylinder engine, intended for economical road use while benefiting from the Cotton triangulated frame.
Model 2
Villiers-powered road model with minor specification upgrades, aimed at everyday riders seeking improved reliability and handling.
Model 3
Cotton road model using a side-valve Blackburne engine, offering smoother power delivery and increased refinement.
Model 4
A higher-capacity Blackburne side-valve Cotton, providing stronger performance while retaining the lightweight chassis.
Model 5
Sporting road model, typically fitted with a Blackburne engine, tuned for improved speed and responsiveness.
Model 6
Competition-oriented Cotton, offered with Blackburne engines, reflecting the marque’s growing racing reputation.
Model 7
A well-known sporting Cotton, available with Blackburne overhead-valve (OHV) power, combining higher rev capability with excellent road holding.
Model 8
Enhanced sports model, continuing the use of Blackburne engines, with refinements to frame geometry and riding position.
Model 9
High-performance Cotton aimed at sporting riders and private racers, benefiting from advanced Blackburne engine options.
Model 10
Top-level sporting machine of the numbered series, representing the most developed form of Cotton’s triangulated-frame concept.
Model 11
The final model in the early numbered range, consolidating Cotton’s experience with Villiers and Blackburne engines before the transition to named model designations.
Main Models 1923
247cc Villiers (2-Speed)
Lightweight two-stroke machine fitted with a Villiers engine and belt final drive. Popular for reliability and economy.
249cc Blackburne Side-Valve
Single-cylinder road model offering smooth delivery and improved refinement.
348cc Blackburne Side-Valve
Stronger mid-capacity machine suited to sporting road use.
348cc Blackburne OHV (Sporting)
Competition-oriented model closely linked to Cotton’s TT activities.
Cotton, The Motorcycle Masterpiece ®
Main Models 1924
250cc Villiers Lightweight
Economical road machine maintaining Cotton’s advanced chassis structure.
350cc Blackburne OHV
Core sporting model offering strong performance and racing potential.
350cc TT-Type
High-performance version inspired by TT competition success.
500cc Blackburne
Large-capacity sporting mount for experienced riders and endurance events.
Cotton, The Motorcycle Masterpiece ®
Main Models 1925
250cc Villiers
Reliable lightweight model continuing in the range.
350cc Blackburne OHV
One of Cotton’s most important sporting machines.
350cc Competition Model
Built specifically for racing and high-performance riding.
500cc Blackburne OHV
High-capacity sporting model delivering strong torque and stability.