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AJS Motorcycles – 8 Classic Bikes

AJS Motorcycles is one of the longest surviving British motorcycle companies to date. Founded in Wolverhampton, the Stevens brothers, Harry, Joe Junior, George and the company’s namesake Albert John (or Jack, as he was more popularly known as) created AJS in 1909. It was their dream to manufacture a motorcycle to win at the Isle of Man TT races.

History of AJS Motorcycles

The first motorcycle AJS produced was the 298 cc Model A. They specifically designed it to come within the 300 cc limit in order to enter the Junior class at the Isle of Man TT. It made its first public appearance at the Olympia Motorcycle Show in 1910.

Four years later, the Stevens Brothers finally achieved their goal. Eric Williams won the Junior race of the last Isle of Man TT on a custom-built AJS, just before the outbreak of the First World War in 1914.

After the war, AJS continued their winning spell at the resumed Isle of Man TT for a few years. In 1931, after several unsuccessful models and racing campaigns, AJS fell into financial woes and declared bankruptcy. However the legacy AJS had created for itself was not yet over, with Matchless Motorcycles, owned by Henry and Charles Colliers, buying them out.

In 1938, AJS and Matchless became part of Associated Motor Cycles. AMC was not a manufacturer, but the parent company of a group of motorcycle manufacturers which included AJS, Matchless, Norton, Sunbeam, James, Francis-Barnett and more. Matchless and AJS shared the same models going forward but used different branding, although the AJS name was applied to a handful of exclusive race machines to continue with its strong racing heritage.

Associated Motor Cycles was acquired In 1966 by Manganese Bronze Holdings, which formed Norton-Villiers to oversee operations. With poor sales figures, they decided to re-manufacture the AJS and Matchless models with Norton engines to increase their appeal. This move proved unsuccessful and they discontinued all production in 1969.

In 1974 the former AJS Competition Manager and racer, Fluff Brown, bought AJS from Norton-Villiers and began production of the AJS Stormer in a new factory in Andover, Hampshire. They were also granted the rights to operate under the name FB-AJS. FB-AJS officially became AJS Motorcycles Ltd. in August 1987.

Nick Brown took over AJS from his father in 2013 after Fluff’s death. AJS currently produces small capacity lightweight retro motorcycles that are exported globally.

AJS Model D

This AJS Model D was sold by Bonhams in April 2019 for £17,250
This AJS Model D was sold by Bonhams in April 2019 for £17,250

The 698 cc Model D made its debut at the Olympia Motorcycle Show in 1912. It featured a cast aluminium silencer, a tubular diamond frame, and quick detachable wheels. They also produced a sidecar version which proved to be so popular that AJS could not keep up with demand. Just as AJS were getting a foothold, the First World War broke out, halting all production.

After the war ended in 1918, AJS relaunched the Model D with a larger capacity 748 cc, 6 bhp engine along with a new saddle and fuel tank. 

The next Model D was launched at the Olympia Motorcycle Show in 1920, coming with another capacity increase to 799 cc and boasting a power output of 7 bhp. The Model D1 followed 1923 and its cheaper price tag increased sales tenfold, making 1924 the best year of sales for AJS.

Prices for a secondhand Model D vary from £12,000 to £24,000 with the larger capacity variants fetching the steeper prices.

AJS S3 V-twin

AJS S3 V-twin
This was the last 1931 Model S3 to be put up for sale and it fetched £ 21,850 at auction back in 2008

The 496 cc V-Twin AJS S3 was released in 1931. It was expensive to develop, and at £65 (£4,500 in 2021) cost more than most bikes of that time. The reason for such an expense? AJS had taken their car manufacturing knowledge and applied it to the S3. 

AJS introduced a coil ignition system to the S3. This required a dynamo and battery in order to function correctly. To further utilise these components they installed electric lights, counter to what many motorcycles at the time that used the cheaper and less effective acetylene lights. AJS had also mounted the V-Twin engine sideways, resulting in the two cylinder heads emerging from under the fuel tank, enhancing the look of an already beautiful machine.

Despite the technology, AJS had priced themselves out of the market. Infrequent sales led to the S3 being discontinued when Matchless Motorcycles purchased AJS at the end of the year. A sports version was due to follow but never made it off the drawing board.

With such a short production run, only a few S3s were produced and even less have survived, making it a very rare bike. The last available for sale sold at auction for £22,000 in 2008.


A rare clip of an AJS V4 fired up and running. It was recorded in 2007

In 1935, at the Olympia Show, the air-cooled 495 cc AJS V4 prototype launched. This prototype was a road going bike but never made it into production. 

Rather than consigning the V4 to the history books, AJS changed it into a racing version that produced 51.5 bhp at 6000 rpm. In early 1936, equipped with a supercharger, the V4 conducted its first test at Brooklands. 

Later that year, AJS entered two V4 factor bikes in the Isle of Man Senior TT with both suffering mechanical problems and as a result, failing to finish.

Two years later, a new AJS V4 appeared at the Senior Isle of Man TT. Fate repeated itself, and after just two laps it retired from overheating.

Following a complete redesign in 1939, the V4 returned with a brand new water-cooled engine producing 55 bhp @ 7200 rpm. A new duplex frame, girder forks and front brake also featured. 

At the 1937 Senior race at the Isle of Man TT, the new water-cooled V4s finally broke their run of bad luck and finished 11th and 13th. Both riders reported the bike was quick, however did not handle well.

The Ulster GP followed shortly after and the V4s led the race from the start. Disaster inevitably struck halfway round the first lap, and the first V4 retired due to spark plug issues. The second of the two bikes held out until the third lap when it too had to call it a day due to a broken fork link, but not before breaking the average lap record of 100.03 mph (160.98 km/h). The Ulster GP would be the last race run that year and for many years to come due to the outbreak of the Second World War.

When racing finally returned, the V4 finally got its long-awaited victory at Chimay, Belgium, in 1946.

AJS built the V4 exclusively for the factory racing team, so never made it into the public’s hands. No original examples have appeared on the market for sale.

AJS Porcupine

Join Dave Roper as he takes an AJS Porcupine out for a lap at the Classic TT

The AJS Porcupine was another AJS racing motorcycle built in 1945. Its original E90S engine was an aluminium 500 cc Parallel-Twin, intentionally designed to be horizontal to leave space for a supercharger and keep the centre of gravity low. Ironically, the FICM banned supercharging the following year, leaving AJS to re-engineer the E90S to work without the intended supercharger. 

The AJS Porcupine made its debut at the 1947 Isle of Man TT but mechanical issues plagued the bike and it finished down in a lowly 15th place. In 1949, after undergoing improvement, victory was finally on the cards for the Porcupine and it secured the inaugural title of the FIM 500 cc World Championship. This would be the only World Championship AJS would ever win.

The next evolution of the Porcupine would arrive in 1953. Its new E95 engine had the cylinders adjusted for more efficient cooling and an improved output of 55 bhp at 7600 rpm. 

Only four of the E95 Porcupine models were ever produced, with the last one sold at a private auction in 2011 for $680,000.

AJS Model 16

This 1953 AJS Model 16 sold for £3895

Developed in 1945 from the military Matchless G3/L World War II motorcycle, the Model 16, with its 350 cc single-cylinder engine, needed minimal maintenance and was extremely economical.

The Model 16 was almost identical to the Matchless G3L, with the only difference being the AJS had a magneto at the front of the cylinder barrel, while the Matchless had it at the rear. 

AJS bestowed several updates on the Model 16 from its launch until 1957: a pivoted rear suspension, dampened spring units, a dual seat, a four-speed gearbox, alloy casing and a crankshaft mounted alternator.

The Model 16M (as it was now known) was also a favourite in trials competitions. Noticing this, AJS created a specific “MC” model with an upgraded tubular frame, new exhaust design, reduced weight and improved ground clearance.

Using the new Model 16 MC, the AJS factory team would win the Scottish Six Days Trial sevens year in a row from 1949 onwards.

In 1964 the AJS Model 16C was launched with a completely redesigned 348 cc engine, producing 16 bhp at 5,600 rpm. In order to help increase sales in America, AJS rebranded the export Model 16 with the new name “The Sceptre” with metal tank badges and steel flywheels. All Model 16 production was discontinued in 1966.

Several original Model 16s are available online for sale from £3,500 – £4,500, with fully restored versions priced around £6,500.

AJS Model 18

Have a listen to this 1954 AJS 18CS

The AJS 500 cc Model 18 launched alongside its smaller capacity sibling, the Model 16, in 1945. It represented the last of the big British singles, as the focus had moved onto developing and using the Norton twins after AMC had merged with Norton.

The Model 18 still held onto the same basic design from the AJS V4 from the 1930s with updates applied to it as they became available. The springer frame rear suspension that the Model 16 received in 1949, was also installed on the Model 18 and renamed the Model 18S.

The ”’Candlestick” shocks which were highly praised for their “springy” comfort were unfortunately prone to oil leaks and hence replaced in 1951 by the larger “Jampot” shocks.

A competition variant was developed in 1951, the Model 18CS, followed by an update to the engine in 1956, giving the bike an output of 28 bhp at 5600 rpm.

The Model 18 was also rebranded “The Statesman” for their export model in 1964 for the American market. Production ended shortly after in 1966.

Unrestored secondhand models are available between £4,500 – £5,500. However a fully restored Model 18 is currently priced around £9,000.


Great clip of someone taking the 7R for a lap at Daytona. Not half bad for a 60 year old ride

Built from 1948 to 1963, the 350 cc 7R was another successful racing bike produced by AJS. Commonly known as the “Boy Racer”, it was produced as a reasonably priced customer racing machine.

The 7R lacked power compared to its competitors when it first launched, producing 32 bhp at 7500 rpm. Despite this it proved popular with privateers due to its lower costs and good reliability. 

In 1951, AJS developed a three-valve head version of the 7R called the AJS 7R3. With its new engine generating 36 bhp @ 7500 rpm, the 7RS performed reasonably well in its first year of racing before the Italians fought back the following year with their own improvements. 

For 1954, AJS developed the 7R3 even further, lowering the engine in the frame for a better centre of gravity, and increasing the power output to 40 bhp at 7200 rpm. These improvements produced immediate results with the 7R3 winning the first two rounds of the World Championship and the Junior class at the Isle of Man TT. 

AJS would later withdraw from racing and create a road version of the standard two-valve AJS 7R. A 500 cc version was also produced, although it was badged as the Matchless G50.

A few models are available  for sale at the time of writing, but come with a price tag around £25,000. In 2018 ten fully restored 7R bikes went up for sale for £400,000! Whoever purchased them would certainly have enough spares for a while.

AJS Model 31

The Model 31 was developed in 1958 specifically for the growing American market (It was also badged as a Matchless G12). Keeping in mind America’s love of “bigger is better”, AJS knew they needed to produce a larger capacity machine and decided on 650cc. 

To keep manufacturing costs low, AJS wanted to use as many parts as possible from the outgoing 600cc Model 30. Now at 650cc, the capacity was now as high as the engine would allow, this meant AJS needed to develop a more robust crankshaft and chaincase to support this larger power output. With this in mind they took the opportunity to include their newly developed alternator as well.

The following year, AJS updated the Model 31 with a tubular frame, lighter cylinder head and a more robust crankshaft to reduce vibrations. This variant, christened the Model 31 De Luxe, became popular in its target American market with it exceeding the magical 100 mph. 

The AJS Model 31 CSR followed the De Luxe in 1963. CSR stood for Competition / Springer / Road and was designed to be a high performance road bike. It did however, turn out to be both uncomfortable and unreliable. 

The AJS Chief Engineer, Jack Williams, stepped in to fix the problems and also alter the bike for racing. This proved to be a successful campaign for the CSR, winning the Thruxton 500 endurance race the same year, earning the name “Hurricane”.

Production of the Model 31 range ended in 1966 when AMC hit financial difficulties.

Current secondhand market value for a low mileage early Model 31 is around £6500-£8000

Have a look around this gorgeous AJS Model 31

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Tom Lucas

Tuesday 11th of October 2022

I would like to learn more about the 1958 AJS cs 31. I have one now, with a spare motor. Any idea how many were made, or how many exist today.

All information would be greatly appreciated.


Murray Jones

Tuesday 18th of April 2023

@Tom Lucas, Hi Tom , Where to start? Well I to have a 1958 AJS model 31CS and a Matchless G11CS. I have restored the matchless but have not been able to find the quick disconnect plug for the headlight or the rubber tube to connect the air cleaner to the carburettor. The matchy is in road trim ie bigger tank and 19 inch front wheel. The AJS in scrambles trim ( yet to be restored). This bike was exported to cooper motors USA but the Matchless direct to New Zealand ( the only one to come here by all accounts , 2 were exported to Australia also. The AJS has been verified by the owners club dating serves as being assembled in September 1957 for the 1958 model year ( new models were released after the Earls court show. Not much is known about how many were produced but the best I have worked out over the years is a total around 150 in both 600cc and 650cc with most being in Matchless trim so AJS versions are fewer worldwide. My AJS would have been out of the first few weeks of production. Thes early engines run type 1 pistons ( very hard to get hands on) in 1959 the barrels gain an extra fin and type 2 pistons . My engine came fitted with type 2 pistons and a spacer fitted under the barrel ( basic difference is the Gudgen pin height is different ) I too would like to learn more about this model ! One story goes that it was Cooper motors who went back to AMC wanting more capacity than 600cc as the other manufactures like BSA and Triumph were selling 650 cc bikes in direct completion in desert racing and that is how the 650 came about by stroking the 600CS . Is that fact ? Quite possibly but who knows . Reguards Murray