AJS Motorcycles

Today in Motorcycle History

AJS S3 496cc Transverse V-Twin 1931

A Spectacular Example of British Innovation

Otro lujoso modelo de AJS que debutó en tiempos difíciles...

1931 AJS Model S3

La AJS S3 fue un brillante e intrépido diseño de la firma AJ Stevens de Woverhampton. Por desgracia, su lanzamiento no podía haber llegado en peor momento. Eran los años de la Depresión y en breve Matchless tomaría control de AJS, postergando este modelo para ofrecer su Silver Arrow… al menos por un par de años mas.

Motor: Bicilíndrico transversal en V a 50 grados, válvulas laterales

Cilindrada: 496cc

Diámetro x carrera: 65 x 75mm

Lubricación: alimentación forzada a las bielas. Sistema de pérdida total.

Carburador: Amal

Ignición: batería 6v /bobina con distribuidor Lucas

Caja de velocidades: 3 velocidades de fabricación propia

Transmisión: primaria por eje a la caja de cambios a través de embrague multidisco, transmisión final a cadena

Cuadro: semi-duplex full loop

Suspensión: horquilla paralelogramo deformable tipo Webb de fabricación propia, trasera rígida

Neumáticos: delantero 325 x 19”, trasero 350 x 19in (originalmente ambos 26 x 3.25”)

Frenos: tambores delantero y trasero de 7” Lado Izquierdo

Capacidad del tanque de combustible: 3 galones

Equipamiento: amperimetro de serie, velocímetro y reloj accesorios opcionales

Altura del asiento: 26”

Distancia entre ejes: 56”

Peso: 330 libras

Velocidad máxima: 65 mph (aproximado)

Precio de nueva: £65

The 1931 AJS Model S3 was a brilliant and intrepid design by AJ Stevens of Wolverhampton. Unfortunately, this debut could not have taken place at a worse time. It was the height of the Great Depression and soon Matchless would take control of AJS, postponing this model in favour of the Silver Arrow.

Among the many technical features, the the camshafts were mounted at the front of the engine and were driven by chain from the crankshaft. This part of the design was borrowed from the factory racers. The cams were mounted immediately beneath the valves with which they were in direct contact.

A bevel gear at the rear of the gearbox transferred power to the countershaft, with the drive chain running within a full enclosure.

The machine was finished with a chrome petrol tank upon which was mounted the instrument panel, the remainder of the machine rendered in gloss black offset by tan saddle and leather-fronted pannier bags. Truly a work of art.


Motor: Narrow-angle V-twin of 50 degrees with sidevalves.

Displacement: 496cc

Diameter x stroke: 65 x 75mm

Lubrication: forced feed to the connecting rods. Total loss system.

Carburetor: Amal

Ignition: 6v battery / coil with Lucas distributor

Gearbox: 3 speed box made in-house

Transmission: primary drive to gearbox via shaft and multi-disc clutch, final transmission by chain

Frame: semi-duplex full loop

Suspension: parallelogram Webb fork, rigid rear

Tires: front 325 x 19in, rear 350 x 19in (originally both 26 x 3.25")

Brakes: 7 " diameter drum brakes front and rear

Fuel tank capacity: 3 gallons

Equipment: ammeter, speedometer and timepiece were optional accessories

Seat height: 26 "

Wheelbase: 56 "

Weight: 330 lbs.

Maximum speed: 65 mph (approx.)

New price: £65

Examples of the S3 are displayed at the Sammy Miller Museum and the National Motorcycle Museum, UK. There are believed to be several more in private hands, with one source giving a total of 8 known examples.

Source: Sergio Scalerandi

One of the ten S3 V-Twins was in Romania in the late 1930s. Probably was very expensive. ~ Dan Melinte

The western half of Moldavia is now part of Romania, the eastern side belongs to the Republic of Moldova, while the northern and southeastern parts are territories of Ukraine. ~ Wikipedia

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