1935 AJS V4 Replica

Replica of a 4-cylinder bike never sold by AJS

| January/February 2011

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    Dan started with a solitary black-and-white photograph and a cutaway drawing — not an engineering drawing but a line drawing showing the general layout of the engine internals.
    Photo by Aaron Steadman
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    Dan Smith's 1935 AJS V4 replica based on the prototype of a motorcycle AJS never offered for sale.
    Photo by Aaron Steadman
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    The V4 burst into life with a throaty rasp from the four exhausts — not smooth like an inline four, but with a ragged bea
    Photo by Aaron Steadman
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    Photo by Aaron Steadman
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    Magneto plate shows "AJ4."
    Photo by Aaron Steadman
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    It’s hard to believe this isn’t a restored original, but it couldn’t be, as AJS never put its V4 into production. Excepting the hand built engine, the rest of the bike is period-correct, with most parts sourced from a mid-1930s AJS 350cc sidevalve single.
    Photo by Aaron Steadman
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    Dan Smith with the finished bike.
    Photo by Aaron Steadman
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    Trial fitting cylinder heads and cylinder patterns to engine case.
    Photo by Aaron Steadman

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1935 AJS V4 Replica
Engine:
495cc air-cooled SOHC 50-degree V4, 50mm x 63mm bore and stroke, 10:1 compression ratio, 40hp @ 6,000rpm (est.)
Carburetion: Two Amal with dual remote floats
Transmission: 4-speed, chain final drive
Electrics: 6v, DC generator, dual twin-spark magneto ignition
Frame/wheelbase: AJS “Denly” single downtube steel frame/55in (1,397mm)
Suspension: Girder fork front, rigid rear
Brakes: SLS drum front and rear
Tires: 100/90 x 19in front, 100/90 x 18in rear
Weight: 450lb (205kg)
Seat height: 29in (737mm)
Fuel capacity/MPG: 5gal (19ltr)/NA

The word “unique” has a simple meaning: it means there’s only one of a kind. Things can’t be “quite unique” or “almost unique.” Either they are or they aren’t. Take Dan Smith’s AJS V4. It’s unique. There’s only one. And that’s because Dan built it himself.

Many of us can turn a wrench to do basic bike maintenance. Some of us are capable of restoring a rusty barn find to its original state, perhaps even making parts where the originals no longer exist. But very few of us can build a complete motorcycle engine from bare metal.

With the aid of drawings, a capable machinist could probably shape the parts from billet using CAD and a CNC mill. But what if there were no drawings, or even a model to work from? That didn’t stop Dan, who designed, cast, machined and assembled his V4 from a black-and-white period photograph and a cutaway sketch of the 1936 prototype. Oh, and if you didn’t know AJS built an air-cooled V-4, you’re not alone!



A little AJS V4 background

The Wolverhampton firm of A.J. Stevens earned a solid sporting reputation during the 1920s with their racing “Big Port” 350cc singles, while also building sturdy side-valve V-twins for sidecar use.

Unfortunately, the financial collapse of 1929 scuttled AJS, and the rival Collier Brothers of Plumstead, London, makers of Matchless motorcycles, snapped them up. Though they had a sporting reputation of their own (a Matchless won the single-cylinder class in the first Isle of Man TT race in 1907), the Colliers intended to exploit AJS’s racing heritage, hence the motorcycle that was the sensation of the 1935 Earls Court show in London: a Bert Collier designed air-cooled overhead cam V4 dressed in AJS livery. It was displayed with lights and generator as a fast road model, but exposed “hairpin” valve springs and space for a supercharger suggested it might be raced too.






November December Vintage Motorcycle Events

Blue Moon Cycle Euro Bike Swap Meet and Vintage Ride


Make plans for the 28th Annual Blue Moon Cycle Euro Bike Swap Meet on Saturday, Oct. 27, followed by the Blue Moon Cycle Vintage Ride on Sunday, Oct. 28!

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