AJS Motorcycles

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AJS 990cc OHC V-Twin


AJS 990cc OHC V-Twin, 1930

Verano de 1930: cerca de la época de su primera presentación, el piloto O. M. Baldwin y la AJS de 990cc.
Summer of 1930, near the time of its first presentation, O. M. Baldwin and the AJS 990cc.


AJS 996cc OHC V-Twin, 1933

En 1933, ahora con 996 cc. Se había trabajado mucho en la moto, ahora estaba equipada con un enorme sobrealimentador en la vieja posición del magneto y tenía un gran carburador frontal.
In 1933, now 996cc. Considerable work had been done on the machine which new sported a huge supercharger in the old magneto position and had a large downdraft carburetor.

1929 AJS ohc v-twin, 990cc Una belleza que no logró su objetivo

Si, ya sé, casi todos hemos visto alguna vez esta foto de Baldwin y su AJS en 1930, pero ¿que sabemos realmente de ella? Construida para intentar el record de velocidad de motocicleta, AJS utilizó dos cilindros de sus motos serie 'K' monocilindricas OHC impulsadas por cadena, en un cárter común, con una tercera cadena de transmisión para el magneto en la parte delantera del motor. Mediante la integración de las 3 cadenas por lo tanto, crearon un motor verdaderamente de ensueño; visualmente equilibrado, con el agregado de un toque de finura técnica. El largo tanque cónico que parecía de otra época y ese tren de distribución hacen de esta moto una joya de todos los tiempos. En el verano de 1930 piloteada por O M Baldwin hizo solo 130 mph, no lo bastante rápido, puesto que el record en ese momento era de 150 mph. Fue desarrollada posteriormente en 1933 por Percy Brewster quien le incorporó un compresor, lo que hizo que perdiera la delicada belleza original. Piloteada por Joe Wright otra vez logró solo 130 mph.

La moto tenía unos cuantos problemas y después de un tiempo (en 1939) terminó en Tasmania, donde en 1940 estableció el record nacional al lograr 120 mph y luego permaneció prácticamente abandonada hasta que en los años 80 fue devuelta al Reino Unido y completamente restaurada se exhibe en el Museo Nacional de la Motocicleta en Inglaterra.

Motor: V-twin a 50° de 990 cc. (79 x 101) OHC comandado a cadenas. Relación de compresión: 10.5 a 1. Posteriormente en 1933 se modificó a 996 cc. y se el agregó un compresor.

Alimentación: dos carburadores

Compresor: Power Plus colocado frontalmente en lugar del magneto y luego sobre la caja de cambios.

Caja de cambios: Sturmey Archer de tres velocidades con relaciones de 3.2, 4.3 y 7.8 : 1

A beauty that did not achieve its goal

Many will be familiar with the photograph of Baldwin and his AJS in 1930, but what do we really know about it?

Built to attempt the motorcycle speed record, AJS used two cylinders from its OHC single cylinder chain-driven 'K' motorcycles on a common crankcase, with a third transmission chain for the magneto in the front of the engine. By integrating the three chains they created a true dream engine; visually balanced, with the addition of a touch of technical finesse. The long conical tank which hailed from another era and that distribution train make this bike a jewel. In the summer of 1930 piloted by O. M. Baldwin coaxed it to only 130 mph; not fast enough, as the record at the time was 137 mph (OEC, Arpajon). It was further developed in 1933 by Percy Brewster who incorporated a compressor, enhancing neither its original beauty nor its performance. Ridden by Joe Wright again it achieved only 130 mph.1

The machine had a few problems.

In 1934 it was sold by Colliers for £85 to Charles Mortimer Sr. who sold it the following year to none other than Eric Fernihough. Eric died in 1938 and the machine reappeared in Tasmania, owned by the Jowett brothers of Launceston who had bought it from the estate2. It was then sold to Reg Monro (also of Launceston) and in 1940 it achieved 120 mph, establishing a new Australian speed record with Reg at the helm.

For a time it was fitted with a sidecar, and then remained dormant but not forgotten (it was *very* well known in Australia) until in the 1980s it was returned to the United Kingdom and completely restored.

It is on exhibition at the National Motorcycle Museum in England.


Engine: 50° 990 cc (79 x 101mm) OHC V-twin, camshaft driven by chains.
Compression ratio: 10.5 to 1.
Induction: two carburettors, one at the rear of each cylinder.
In 1933 capacity was increased to 996 cc. and a supercharger was added. A single large-bore downdraft carburettor was fitted.
It appears that at this time the original aluminium heads were changed for aluminium bronze with no valve seat inserts, and the milled steel barrels had been exchanged for conventional cast iron.
Compressor: Power Plus located initially forward of the magneto, and then above the gearbox.
Gearbox: Sturmey-Archer three-speed with ratios of 3.2, 4.3 and 7.8: 1

"Just after clocking more than 130 mph at Arpajon on its first Maximum Speed Record attempt outing ridden by Capt O.M. Baldwin, further runs had to be abandoned because of the tendency of the piston of the rear cylinder to seize. The engine was a 50 degs. V-twin of 990c.c. (79 x 101mm.) with chain-driven overhead-camshafts. There were two carburetters; both inlet ports faced to the rear and the exhaust ports to the front. The cylinder barrels were of steel and the heads of light alloy with cast-iron valve seats inserted. The frame had a very large top tube, 2 1/2-in diameter, the wheel hubs were machined from solid steel, and the handlebars were in two halves.

The Motor Cycle July 24th, 1930 (probably)

1. 130 mph is fast, certainly, but it's worth noting that in 1907 aviation legend Glenn Curtiss achieved an astonishing 136.27 mph.
2. E & W.H. Jowett (Trevor and Wilfred), 238 Charles Street, Launceston, Tasmania. AJS and Triumph Agents.
Reg Monro was a WWII pilot, as was E.J. (Jock) Walkem, another major player in the story. David Dowd (Bluey), who has written an informative first-hand account, was also involved in aviation.
In 2010 the motorcycle world speed record stood at 376.36 mph (605.69 km/h).

Sources: Sergio Scalerandi, archives.jampot.dk, Howard Burrows.

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