AJS were a powerhouse of the motorcycle industry in the 1920s. They were a typical British firm that were mad about single cylinder bikes, however as this decade moved forward, manufacturers in the UK looked at what what was happening across the pond and started to toy with the four cylinder concept. The configuration had many advantages, and one disadvantage – that being the cost of manufacture.
The idea of AJS building a four cylinder motorcycle seemed unlikely, but as the 1920s rolled on, the future seemed solid. Although four cylinder bikes had been around for some time, in particular in America with the likes of Indian and Henderson, the idea was relatively untested in the UK.
It was time for AJS to test the water, and this came in the late 1920s with this wonderful piece of engineering, that had a lot of potential in the ever-evolving industry.
The prototype was powered by a 632cc air-cooled OHV longitudinal in-line four. It featured a three-bearing camshaft, driven by a chain from the front end of the crankshaft. It had a detachable cast iron cylinder head, and a built-in gearbox. The oil from the sump was pressure-fed to the rocker box via an external radiator with four tubes. It was an exquisite looking machine and had some serious potential.
The concept was an ill-fated attempt by AJS to kickstart falling sales in the late 20s, and the bike never came to fruition. It could be seen as an untimely by-product of the Great Depression as manufacturing costs soared, and disposable income took a slap to the face.
It is believed that at least two 4-cylinder prototypes were built in the late 1920s, one of which has survived and which has been resurrected by the Sammy Miller Motorcycle Museum. Check out the video below (The Classic Motorcycle Channel) that shows the bike running at the VMCC Banbury Run.
an article by The Girder Club
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