1953 AJS 18S
Engine: 498cc OHV air-cooled single, 82.3mm x 93mm bore and stroke, 6.26:1 compression ratio, 18-25hp @ 5,400rpm (figure varies by source)
Top speed: 80-85mph (est.)
Carburetion: Single Amal 89B
Transmission: 4-speed, chain final drive
Electrics: 6v, magneto ignition
Frame/wheelbase: Single downtube steel cradle/57.25in (1,454mm)
Suspension: Telescopic forks front, dual shocks rear
Brakes: 7in (178mm) SLS drum front and rear
Tires: 3.25 x 19in front and rear
Seat height: 31in (787mm)
Fuel capacity: 3.6gal U.S. (13.6ltr)
Weight (dry): 386lb (175kg)
Price then/now: $400(est.)/$4,000-$8,000
“Motorcycling is one of the most economical and pleasurable modes of transport. It is our sincere wish that every AJS owner should obtain, from his mount, the service, comfort and innumerable miles of low-cost travel that we have earnestly endeavored to build into it.”
— From the 1953 AJS maintenance manual
Once upon a time, there were people who liked slow motorcycles. People whose sole transportation was a motorcycle, and who expected their motorcycles to get them to work, rain or shine. They wanted a motorcycle that was reliable, sipped gas and could be repaired in the back yard. Speed was optional.
And while this type of motorcycling went out of fashion in the United States around World War I, it persisted in England and Europe until the early 1960s. Indeed, English motorcycle manufacturers prospered by building simple, economical bikes. The annual lineup may have featured a sport bike that grabbed headlines and won races, but the factory made most of its money building small, simple, slow bikes for the economy minded everyday rider.
One of these English manufacturers was Associated Motor Cycles (AMC), a conglomerate that manufactured several different brands including Matchless and, after 1931, AJS motorcycles.
AJS motorcycles beginnings
AJS was started by the Stevens family, who produced their first complete motorcycle in 1909. The company prospered until the 1929 stock market crash, when financial reverses led to its sale to AMC in 1931. As the Thirties progressed, AJS and Matchless street machines began to look more and more alike, although the race departments remained separate. After World War II, the only mechanical difference between AJS and Matchless road bikes was that “Ajays” had the magneto in front of the engine, while Matchless machines had the mag in the rear.
During World War II, AMC built thousands of 347cc Matchless G3L singles for the Allies. Importantly, the G3L was the first English-built bike to feature telescopic forks. Shortly after Germany surrendered, AMC announced a civilian version of the G3L, the AJS Model 16. The sturdy pushrod overhead valve engine featured heavy cast iron flywheels for a lot of inertia and low-end torque. The connecting rod ran on three rows of caged roller bearings. Lubrication was dry sump, and ignition was by Lucas magneto and separate Lucas generator (cue the “Prince of Darkness” jokes). The four-speed gearbox was made by Burman, an independent firm that made gearboxes for several different English motorcycles.
Despite its reputation for reliability, the Model 16 engine had some quirks. The timing side shaft was not keyed to the flywheel but instead used a taper fit and nut; service manuals recommended that bottom-end rebuilders use a special jig to line everything up. The sheet metal primary case cover was determined to leak, despite the best efforts on the part of loyal owners, and the gearbox return spring broke on a regular basis.
Enter the AJS Model 18
In 1946, a big brother to the Model 16 joined the AJS lineup. The 498cc Model 18 had a bore and stroke of 82.3mm x 95mm. It weighed 349 pounds and, like many machines of its era, had a rigid rear end. It was reliable, easy to work on and, with a compression ratio of 5.9:1, would run on low octane “Pool” gasoline, the only gas available in England at the time.
Long-stroke singles like the Model 18 were something of a mainstay for the British motorcycle industry. Nicknamed Thumpers or Bangers and sought out as basic transportation, they were also enjoyed by enthusiasts for what they were; slow, good handling, torquey beasts of burden, excellent for a quiet ride in the country. Following World War II, the English government was anxious to retire its massive war debt, and pushed manufacturers to expand their markets and export as much as possible. As a result, British motorcycles started trickling into the U.S. British bikes started to get a firm foothold in the U.S., and in November 1949 the Indian Motocycle Company, as a condition of a $1.5 million loan from an English firm named Brockhouse, agreed to use its dealer network to sell a variety of English motorcycles, including AJS.
Yet AJS heavyweight singles were not very popular in the U.S. as most American riders were interested in fast road bikes or nimble enduro bikes, an increasingly popular category. The main market for the staid and simple Ajay singles continued to be English and British Commonwealth working people.
In 1949, rear suspension became available for an extra 20 pounds sterling. The next year, an all aluminum alloy engine appeared for offroad competition versions of the single, while the roadsters enjoyed an aluminum head with iron valve seat inserts. Distinctive, fat rear shocks known as “Jampots” appeared in 1951, resulting in the slender rear shocks used on earlier bikes being referred to as “Candlesticks.”
Although England had two weekly motorcycle magazines, there are no contemporary road tests of the Model 18, even though it was very popular in its home market. Why? According to British motorcycle journalist Bob Currie, “Because some dastardly road-tester once wrote a mildly critical remark about an AJS (or maybe it was a Matchless) the top brass of the big AMC factory at Plumstead, south-east London, steadfastly refused to supply the motor cycling press with road test models throughout the 1950s.”
Don Johnson’s 1953 AJS 18S
AMC may have had disdain for the motorcycle press, but it kept excellent records. The bike featured here is a 1953 Model 18S, S standing for optional rear suspension. AMC started building the 1953 models in the autumn of 1952, and this bike was completed at AMC’s Plumstead works in December that year. According to AMC factory records, the test rider was a C. Challis, who passed this Model 18S, engine no. 22721, as roadworthy on Dec. 16, 1952. It was then crated up and shipped to P & R Williams, motorcycle dealers in Sydney, Australia, where it sold to an Aussie rider.
The original purchaser must have liked his thumper, for he kept it in excellent condition, and after he went to his earthly reward, his estate sold it to someone in the U.S. named Geoffrey. One day, Geoffrey forgot to turn on the tap that the first owner had installed in the oil line, and the engine seized up.
The bad luck of this Model 18S was matched by the declining fortunes of the factory that made it. In the late Fifties and early Sixties, the wages paid to English workers improved to the point where a working family could afford the inexpensive automobiles that were increasingly occupying the roads of England. At the same time, Japanese motorcycles that didn’t leak and started with the push of a button instead of the swing of a leg became available. Sales of traditional English get-to-work bikes like the AJS declined dramatically, and in less than a decade AMC’s fortunes turned upside down; AMC filed for bankruptcy in August 1966.
Unlike the AMC company, however, this Ajay survived. Even in years past, there were enough thumper fans in the U.S. and elsewhere to give even a non-runner some value. Second owner Geoffrey sold the poor beast to Jeff, a friend of the present owner, Don Johnson. Jeff had planned to restore the Ajay but, as so often happens, life got in the way of the planned restoration, and Jeff decided that it would be better if Don bought the bike. So it was that this Ajay ended up in Don’s garage.
Once he had the bike, Don tore the engine down, hoping that he’d find something simple, like maybe a stuck piston. He didn’t. “I tore it down piece by piece,” Don says. “Everything I looked at wasn’t it. Finally, I got clear down to the crankshaft. The bushing on the timing side was welded to the crankshaft.”
What had at first seemed like a fun project was becoming less fun by the minute. “It took great effort to even get the cases apart,” Don recalls. “The thing was stuck on too tight.” Eventually all the pieces separated, and Don took them to the late Ed LaCruz at Dyna Reno, who rebuilt the crankshaft and trued it up.
Unlike AMC, who was never known for customer service, the members of the AJS-Matchless club will go far out of their way to help someone with a sick AJS. Through them, Don was put in touch with a fellow who used to work at the Plumstead factory and knew exactly how to put a Model 18’s bottom end together. The club also found a crankpin and bushings for Ed to use in the crank rebuild.
Most of the Ajay was original, but the dyno (British for generator) wasn’t. To get it sorted out, Don turned again to England. “Sean Hawker in England was a joy to work with,” Don says. “Efficient, knew his stuff, very helpful. He helped get the right part and helped with putting the electrical system together. I replaced the regulator with an electronic device. Jampot Spares, also in the U.K., had a lot of parts. You can now buy pre-Monobloc carburetors from Burlen Fuel Systems in Salisbury, U.K. They will ship new carbs with jetting as specified. Even with all the help, it was an effort to find all the bits and pieces.”
One item that had Don puzzled was the missing air cleaner. The bike was otherwise complete when purchased, although many parts needed replacing. Checking parts books, Don found there was nothing missing — stock Model 18s had no air cleaner. “An air cleaner was an accessory in 1953. Think about it. England is pretty wet — you don’t really need air cleaners,” Don says. He installed the air cleaner now on the bike, and aside from giving the cycle parts a good cleaning, he left the chassis alone. Remarkably, the chrome and paint are original. “This bike is a mechanical, not a cosmetic restoration. There are some items that are questionable, like the seat with the red piping. AJS bikes were blue or black, and Matchlesses were red, so the seat might have come off a Matchless,” Don adds.
Made to ride
Don owns and rides a lot of bikes, but enjoys the AJS as a slow-down-and-smell-the roses Sunday rider. “It’s fun to work on. Any reasonably competent mechanic can keep it running. It’s almost impossible to keep it from leaking, but if you use a lot of silicone seal, and get the primary cover on just right, you might luck out. My bike drools when it is on the sidestand,” Don says.
Starting a British one lunger is easy — if you follow the specified starting procedure exactly. Don explains: “You turn the fuel tap on and tickle the carburetor. If it’s cool outside, you drop the air slide. You turn the manual advance on the left handlebar to full retard, use the kick starter to get the piston to full compression, pull the compression release, ease the motor over to just beyond top-dead center and give it a good healthy kick. It should start — if you did everything right in the right sequence.”
The manual advance lets the rider tune the bike from the handlebars. “As you adjust the lever, you can feel the bike pulling more or less hard. It compensates if the magneto isn’t timed exactly right,” Don says. The four-speed Burman box shifts nicely, and the brakes actually work. That said, Don notes that the Ajay “isn’t fast enough to test the handling.” And it runs on today’s regular gas, which is considerably higher octane than the miserable gasoline available to British riders in 1953.
“It’s more of a character bike,” Don explains. “People appreciate its patina. Riding it is fun. I have time to see what I am riding through. I like the chronometric dials, they move a little jump at a time. It’s not fast, it’s not powerful, it’s just pleasant to ride. I own a lot of bikes, and I only keep a few licensed. This is one of them.” Slow it might be, but that doesn’t keep this old AJS from being one of the more enjoyable motorcycles made. MC
- 1 year of Motorcycle Classics magazine both print and digital – six premium issues full of exciting and evocative articles and photographs of the most brilliant, unusual and popular motorcycles ever made!
- Special discounted prices on books, t-shirts, and archive products in the Motorcycle Classics Store
- Online access to Motorcycle Classics content dating back to 2005
- Access to exclusive online content - restoration projects, rides & destinations, and gear reviews.
Hello , your account does not have an active membership.
You'll need an active membership to continue reading. Please contact Customer Care at 1-800-880-7567 or visit Customer Care below.