1928 AJS 632CC Four

1928 AJS 632 Four
Claimed power: 20hp @ 4,500rpm (rear wheel, est.)
Top speed: 65mph
Engine: 632cc air-cooled OHV longitudinal inline four, 54mm x 69mm bore and stroke, 6.5:1 compression ratio
Weight (dry): 385lb (175kg)
Fuel capacity: 3.9gal (14.7ltr)

By the 1920s, AJS had established a reputation for solid, dependable motorcycles, primarily robust 350cc singles and larger V-twins for pulling sidecars. The idea of AJS building a 4-cylinder seemed unlikely, yet if it hadn’t been for the Great Depression, the firm might have done just that.

Unfortunately, the Depression forced AJS into bankruptcy, and to become part of the AMC two-wheeled conglomerate. But before that happened AJS, in an ill-fated attempt to kickstart falling sales, produced at least two 4-cylinder prototypes in the late 1920s, one of which has recently been uncovered and restored by Sammy Miller. It’s now on display in his museum alongside the sole surviving 500cc AJS V4 and the title-winning AJS E90 Porcupine.

AJS was born out of the Stevens family’s Black Country screw factory at Wednesfield, near Wolverhampton in the British Midlands. The first motorcycle was built in 1897, powered by an American Mitchell engine. Four of the Stevens brothers — Harry, George, Albert John and Joe Junior — started producing their own engines at the turn of the century, selling them to motorcycle manufacturers such as Wolf and Werner under the Stevens name. The AJS marque was founded in 1909 after the brothers began building complete bikes powered by their own engines, so as not to associate them with the Stevens engines sold to rival manufacturers. Since Albert John (known as Jack) was the only one with a middle initial, they named the firm A.J. Stevens & Co. after him, even though all four brothers were equal partners. MC

More information on the AJS and other vintage bikes:

AJS Motorcycle Ice Racing
1956 AJS 18CS
Sammy Miller Museum

Order the July/August 2012 issue of Motorcycle Classics to read more about the 1928 AJS 632cc Four, including riding impressions by Alan Cathcart. Contact Customer Service at (800) 880-7567 or contact us by email.

Published on May 24, 2012

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