71-401: The AJS 500 cc Porcupine was a British racing motorcycle built by Associated Motor Cycles (AMC), which débuted in 1945 with a horizontal-engine designated E90S. The later E95 model was developed with an inclined-engine. AMC produced AJS and Matchless brands at the time. The motorcycle was originally designed by AJS to be supercharged , as were a number of pre-war racing bikes, but
142-478: A front-wheel drive (fwd) 2+2 car powered by a turbo version of the water cooled Norton wankel engine known as Project Nora. After negotiations with Norton it became apparent that the engine was not sufficiently developed for use. Development of the water cooled engine continued and a water cooled prototype, the P51, was built in 1984. In a joint venture with German Norton importer Joachim "Joe" Seifert, Norton set up
213-438: A 1954 AJS Porcupine E95, using an ex-Tom Arter MKII motor, which features a unique Jack Williams built up roller bearing crankshaft. They use it for exhibition and historic racing. Tom Arter put a complete 1954 E95 AJS Porcupine up for auction, and it sold for $ 228,620. A 1954 AJS E95 Porcupine was sold post-auction at Bonhams in 2011, for $ 675,000 (plus fees). Associated Motor Cycles Associated Motor Cycles (AMC)
284-474: A 250 cc and in 1960 by a 350 cc for a lightweight series of singles. In 1960 leading light Bert Hopwood resigned and joined Triumph at Meriden . That same year AMC posted a profit of a just over £200,000, not so good compared with BSA's £3.5 million. Then in 1961 they posted a loss of £350,000. With the closure of the Norton plant at Birmingham in 1962 and the merger of Norton and Matchless production,
355-532: A 495 cc AJS V4 was built to compete against the supercharged BMWs then dominating racing. The bike was a water-cooled and supercharged design. In 1939 the dry-sump V4 was the first bike to lap the Ulster Grand Prix course at over 100 mph (161 km/h). It weighed 405 lb (184 kg). Its top speed was 135 mph (217 km/h). Then the Second World War intervened. During
426-685: A Norton 750 motor in a G80CS frame, and asked them to build them some. This was the last Matchless motorcycle, the 748 cc G15 which was also sold as the AJS Model 33' and as the Norton P11. The G15 was produced up until 1969. A Mk2 version was sold in Britain from 1964. Matchless/AJS built predictable handling, comfortable, well-made, reliable and economical motorcycles, for their day. Unfortunately such attributes were not enough to keep them in business. Continuing poor sales led to AMC becoming part of
497-534: A UK businessman, bought the rights to Norton from some US concerns and relaunched Norton in its then-new Midlands home at Donington Park where it was to develop the 961cc Norton Commando and a new range of Norton motorcycles. The company went into administration in January 2020. In April 2020, administrators BDO agreed to sell certain aspects of Garner's business to a new business with links to Indian motorcycle producer TVS Motor Company . The original company
568-503: A book of driving hints which also contained details of their Military and Empire models. In May 1918, Norton stated in one of their adverts that 'The ministry are taking the whole of our present output, but we have a waiting list'; this advert also uses the "Unapproachable Norton" phrase. Few Norton WD models appear in the For Sale column of The Motor Cycle after the war, suggesting they were shipped abroad, apparently one order going to
639-655: A family of three similar smaller-capacity twin cylinder machines: first the Norton Jubilee 250 and then the Navigator 350 and the Electra 400 , which had an electric starter. These models were Norton's first use of unit construction . The engine was an entirely new design by Bert Hopwood and the frame and running gear were from the Francis-Barnett range, also owned by AMC. In 1966 AMC became insolvent and
710-406: A larger factory at Deritend Bridge, Floodgate Street, Birmingham. The first Norton engines were made in 1907, with production models available from 1908. These were the 3.5 hp (490 cc) and the 'Big 4' (633cc), beginning a line of side-valve single-cylinder engines which continued with few changes until the late 1950s. The first Norton logo was a fairly simple, art nouveau design, with
781-486: A long history of racing involvement. During the Second World War Norton produced almost 100,000 of the military Model 16 H and Big 4 sidevalve motorcycles. Associated Motor Cycles bought the company in 1953. It was reformed as Norton-Villiers , part of Manganese Bronze Holdings , in 1966, and merged with BSA to form Norton Villiers Triumph in 1973. In late 2008, Stuart Garner ,
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#1732801731919852-420: A low-cost chassis and an engine with long-term reliability. The chassis, designed by Ron Williams and made by Harris Products, was based on Yamaha's Delta box stamped panels. However, in spite of many innovative solutions from Chris Mehew, the team's was unable to improve the reliability of the engine to a commercially saleable level. They quickly realized that an engine generating 1,100 °C exhaust temperatures
923-419: A mistaken belief that this would strengthen the bottom-end to cope with the higher power-output. Instead the resultant crank-bending caused the rollers to "dig-in" to the races, causing rapid failure. This fragility was particularly obvious when measured against the reliability of contemporary Japanese machines. This problem was solved initially by a special roller bearing of 'superblend' fame later in 1972. This
994-520: A modified Norton 16H beat contenders. From 900 in 1936 to 2000 in 1937, Norton was ahead of the competition as war loomed, and there was good reason in terms of spares and maintenance for the military to keep to the same model. Between 1937 and 1945 nearly a quarter (over 100,000) of all British military motorcycles were Nortons, basically the WD 16H (solo) and WD Big Four outfit with driven sidecar wheel. The Isle of Man Senior TT successes continued after
1065-699: A new company, called Norton-Villiers in 1966. Some of the contents of the Norton factory including motorcycles were later auctioned off after the company went into receivership. Four-stroke scrambler production ceased in 1966. Matchless became overshadowed with focusing on BSA, Triumph and Norton from 1960. The more race-worthy Matchless G85CS replaced the G80CS having a purpose-built frame, alloy fuel tank, ultralight hubs, 12:1 compression ratio and GP Amal (carburettor) . Only 150 of these hand built bikes were made. Vic Eastwood, Chris Horsfield, and Dave Nicoll were signed to race these Matchless Motocross bikes. By
1136-618: A planned production of 500 in 1980. However, Poore announced in December 1979 that the launch of the bike was delayed indefinitely due to the political situation surrounding the Triumph cooperative. The company had some success making the Wankel -engined Interpol 2 motorcycle for civilian and military police forces and the RAC which was launched in 1984. In 1981 Lotus Cars planned to build
1207-407: A second has been reconstructed from spares. In 1953 there was a Clubman range of Matchless/AJS 350 cc and 500 cc singles, and the production model Matchless G45 500 twin became available. In 1952 further extended the empire by taking over Norton. Then 1958 saw the introduction of unit construction 250 cc AJS/Matchless machines. From 1948, competition models of the singles were produced which gave
1278-427: A top speed of 209 km/h (130 mph). In 1960, a new version of the road-going Featherbed frame was developed in which the upper frame rails were bent inwards to reduce the width between the rider's knees for greater comfort. The move was also to accommodate the shorter rider as the wide frame made it difficult to reach the ground. This frame is known as the "slimline" frame; the earlier frames then became known as
1349-530: A visit to Norton Motors. Mr Norton had stated that he expected three post-war models, the 3.5 hp 490 cc TT with belt drive (for the 'speed merchant'), and two utility mounts, one with detuned TT engine, and the other being the Big Four for very heavy solo or sidecar work, both of these with three-speed Sturmey-Archer countershaft gearbox and all chain drive. It was also stated that he had been experimenting with aluminium pistons, and that Norton had produced
1420-552: A workers cooperative alone. Despite mounting losses, 1974 saw the release of the 828 Roadster, Mark 2 Hi Rider, JPN Replica ( John Player Norton) and Mark 2a Interstate. In 1975 the range was down to just two models: the electric start Mark 3 Interstate and the Roadster, but then the UK Government asked for a repayment of its loan and refused export credits, further damaging the company's ability to sell abroad. Production of
1491-423: Is claimed to have produced 55 bhp @ 7600 rpm The gear drive for the camshafts was on the right of the motor, while the gear primary drive was on the left. The geared primary drive meant that the motor ran "backwards". The cam gear drive also drove a jackshaft at the rear of the cylinders, which drove an oil pump, a fuel pump , and (via a chain drive ) a Lucas magneto . The four-speed gearbox output
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#17328017319191562-586: The DOHC engine becoming available to favoured racers in 1949. The Short Stroke model (1953 to 1962) had bore and stroke of 86 mm × 85.6 mm (3.4 in × 3.4 in). It used a dry sump 499 cc single-cylinder motor, with two valves operated by bevel drive, shaft driven twin overhead camshafts. Compression ratio was 11:1. It had an Amal GP carburettor, and a Lucas racing magneto. The 1962 500 cc Manx Nortons produced 50 bhp (37 kW) at 6,780rpm, weighed 142 kg (313 lb), and had
1633-509: The Isle of Man Senior TT was the first win with a race average speed over 60 mph, rider Alec Bennett . Norton won this event ten times until they withdrew from racing in 1938. J.L. Norton died in 1925 aged only 56, but he saw his motorcycles win the Senior and sidecar TTs in 1924, specifically with the 500 cc Model 18, Norton's first overhead valve single. Designed by Walter Moore,
1704-518: The Norton CS1 engine appeared in 1927, based closely on the ES2 pushrod engine and using many of its parts. Moore was hired away to NSU in 1930, after which Arthur Carroll designed an entirely new OHC engine destined to become the basis for all later OHC and DOHC Norton singles. (Moore's move to NSU prompted his former staff to quip NSU stood for "Norton Spares Used") The Norton racing legend began in
1775-528: The "wideline". The last Manx Nortons were sold in 1963. Even though Norton had pulled out of Grand Prix racing in 1954, the race-shop at Bracebridge Street continued until 1962, and the Manx became a mainstay of privateer racing, and even today are highly sought after, commanding high prices. On 7 November 1960 the first new 650 cc Norton Manxman was launched for the American market only. By September 1961
1846-406: The 1930s. Of the nine Isle of Man Senior TTs (500 cc) between 1931 and 1939, Norton won seven. Until 1934 Norton bought Sturmey-Archer gearboxes and clutches. When Sturmey discontinued production Norton bought the design rights and had them made by Burman , a manufacturer of proprietary gearboxes. Norton started making military motorcycles again in 1936 after a tender process in 1935 where
1917-743: The Brown family, now imports and retails small capacity motorcycles manufactured in China under the AJS name, whilst maintaining the spares supply for the Stormer models. Norton Motorcycle Company The Norton Motorcycle Company (formerly Norton Motorcycles. ) is a brand of motorcycles headquartered in Solihull , West Midlands, (originally based in Birmingham ), England . For some years around 1990,
1988-586: The Colliers, in 1931 and Sunbeam was added in 1937 from Imperial Chemical Industries . The name of the Matchless Motor Cycles company was changed to "Amalgamated Motor Cycles Ltd" in 1937 and "Associated Motor Cycles (AMC)" in 1938. AMC was not a manufacturer in its own right, but rather the parent company of a group of motorcycle manufacturers which included Matchless, AJS , Norton , James , Francis-Barnett , Sunbeam and others. In 1939
2059-470: The FICM banned supercharging in 1946. The motor was then worked on to allow it to perform without a supercharger. Jock West first rode the machine at the 1947 Isle of Man TT where he experienced teething problems relegating him to a 15th place, although he recorded the third fastest lap time of the race. Leslie Graham then rode the bike to victory in the inaugural 1949 FIM 500cc world championship . This
2130-566: The German company Norton Motors (Deutschland) GmbH. After Poore's death in 1987, Manganese Bronze sold Norton to a group of investors led by Philippe LeRoux for £1.64 million, who formed Norton Group PLC. A civilian version of the Interpol 2 was introduced named the Classic with only 100 bikes being made. Subsequent Norton Wankels were water-cooled. The Commander was launched in 1988 and
2201-622: The Italian multi-cylinder racers. They did well enough in their first year, not as well the second. For 1954 Jack Williams, the works team manager, developed the bike further, lowering the engine in the frame, and making some tuning changes that gave 40 bhp (30 kW) @ 7800 rpm. It immediately won the first two rounds of the World Championship and took first at the Isle of Man TT. These were factory specials, but one has survived, and
AJS Porcupine - Misplaced Pages Continue
2272-535: The Norton 650SS appeared for the UK market, the 750 cc (Atlas). By 20 April 1962 for the American market as they demanded more power, but the increases to the vertical twin engine's capacity caused a vibration problem at 5500 rpm. A 500 cc vertical twin is smoother than a single-cylinder, but if the vertical twin's capacity is enlarged vibration increases. The 750 Norton Atlas proved too expensive and costs could not be reduced. Financial problems gathered. There
2343-541: The OHV single-cylinder machines. Manx Nortons also played a significant role in the development of post war car racing. At the end of 1950, the English national 500 cc regulations were adopted as the new Formula 3 . The JAP Speedway engine had dominated the category initially but the Manx was capable of producing significantly more power and became the engine of choice. Many complete motorcycles were bought in order to strip
2414-623: The Russian Army [1] . The 1913–1917 Red Book listing UK Motor, Marine and Aircraft production shows Norton dropped from a full range in 1916, to only the Military Big Four in 1917. Norton resumed deliveries of civilian motorcycles in April 1919 with models aimed at motorcyclists who enjoyed the reliability and performance offered by long-stroke single-cylinder engines with separate gearboxes. Norton also resumed racing and in 1924
2485-460: The Wankel engine on two main counts: 1. As the team had realised, there was just too much heat to be confined in a motorcycle chassis. 2. The pollution created by the engine burning lubrication oil and fuel was too great to meet the impending pollution regulations without a large and costly exhaust scrubbing system. In his TV Series on British industry, Sir John Harvey-Jones commented that the company
2556-620: The War, Matchless manufactured 80,000 G3 and G3L models for the armed forces. AMC sold the Sunbeam name to BSA in 1943. Post-war landmarks start with the production of Matchless/AJS 350 cc and 500 cc singles, developed from the legendary war-time Matchless G3 produced for the Army. In 1946 Freddie Clarke joined AMC as Chief Development Engineer after a row with his former employers, Triumph , and in 1947 AMC absorbed Francis-Barnett , followed later by
2627-728: The acquisition of James in 1951. In 1949 the first Matchless/AJS vertical twin (500cc) was produced, later to be joined by 600 cc and 650 cc vertical twins in 1956 and 1959 respectively. On the racing front AMC were fielding the AJS Porcupine (500 cc forward-facing parallel twin), the AJS 7R (32 bhp, 350 cc OHC single), the Matchless G50 (a 500 cc variant of the 7R) and by 1951, the Matchless G45 (500 cc vertical twin). The AJS Porcupine had been designed for supercharging, before
2698-413: The big end bearings and the centre main bearings. The outer main bearings were rollers. One problem cited for the engine is the use of non parallel valves with conventional rockers. The 1947 model engine was mostly made of alloy, but, as an experiment, the head was cast in silver for increased thermal efficiency . Due to the softness of silver, it had to be alloyed to make it hard enough for racing use. By
2769-548: The company some memorable wins. AMC withdrew from the world of works and one-off road racing at the end of the 1954, with the death of H.J.'Ike' Hatch, and in the face of fierce competition from the other European bikes. Instead of works specials, AJS and Norton would make the production versions of the Manx Norton and the standard two valve AJS 7R, for privateers. In 1958 the Matchless/AJS road bikes were joined by
2840-426: The engine for 500 cc car racing, as Norton would not sell separate engines. The racing successes were transferred to the street through cafe racers , some of which would use the featherbed frame with an engine from another manufacturer to make a hybrid machine with the best of both worlds. The most famous of these were Tritons - Triumph twin engines in a Norton featherbed frame. Despite, or perhaps because of,
2911-618: The engine slightly up/down, forward/back, or even right/left, could deliver a "sweet spot" in terms of handling. Motorcycle designers still use this method to fine-tune motorcycle handling. In 1951 the Norton Dominator was made available to export markets as the Model 88 with the Featherbed frame. Later, as production of this frame increased, it became a regular production model, and was made in variants for other models, including
AJS Porcupine - Misplaced Pages Continue
2982-426: The export trade. Norton were involved in exporting and earlier that year had announced a new 'Colonial Model' of their 633cc Big 4. This featured an increase in ground clearance from 4.25" to 6.5", by altering the frame, larger tank, greater clearance on mudguards, and a sturdy rear carrier. The engine was unaltered, and transmission was via a Sturmey-Archer 3-speed gearbox. In February 1918, Motor Cycle reported on
3053-624: The flying 5 mile record at 75.88 mph, and the standing start 10 mile record at 73.29 mph, again on the 490 cc Norton. Norton continued production of their 3.5 hp and Big 4 singles well into the war period, though in November 1916 the Ministry of Munitions issued an order that no further work on motor cycles or cars would be allowed from 15 November 1916 without a permit. By this time most motor cycle companies were already either producing munitions (or aircraft parts), or devoted to
3124-442: The future was beginning to look rather bleak. In the sixties, with sales declining AMC made the commercial decision to focus on the Norton twins and the Matchless/AJS singles but they were not to be successful and the factory ceased production shortly afterwards. Some models were "parts bin specials" put together at the request of the American dealers. The Americans were desert racing, so Berliners sent AMC an example custom bike using
3195-462: The gearbox known as the "lay-down" box. More shapely mudguards and tanks completed the more modern styling to Nortons new premium model twin. Norton struggled to reclaim its pre-WWII racing dominance as the single-cylinder machine faced fierce competition from the multi-cylinder Italian machines and AJS from the UK. In the 1949 Grand Prix motorcycle racing season , the first year of the world championship, Norton made only fifth place and AJS won. That
3266-508: The late 1960s, competition from Japan had driven the British motorcycle industry into a precipitous decline. In 1966 AMC collapsed and was reformed as Norton-Villiers under Manganese Bronze Holdings . This only staved off the problems for a little while and Norton-Villiers eventually went into liquidation in 1974. Norton was reformed with financial assistance from the British government as Norton-Villiers-Triumph (NVT) actually incorporating
3337-508: The majority of BSAs motorcycle concerns but omitting the BSA name for Triumph. In part due to a labour dispute, NVT later went into receivership in 1974. Following the final collapse of NVT, the AJS name was bought by former works rider and competition manager Fluff Brown who continued production of the AJS Stormer in 250 and 360cc capacities. The company, AJS Motorcycles, still owned by
3408-459: The name spelled in capitals. However, a new logo appeared on the front of the catalogue for 1914, which was a joint effort by James Norton and his daughter Ethel. It became known as the "curly N" logo, with only the initial letter as a capital, and was used by the company thereafter, first appearing on actual motorcycles in 1915. In 1913 the business declined, and R. T. Shelley & Co., the main creditors, intervened and saved it. Norton Motors Ltd
3479-483: The new Norton Villiers Triumph (NVT) was formed. The Triumph Motorcycles name came from BSA's Triumph subsidiary. 1973 saw the start of development on a new machine with a monocoque pressed steel frame, that also included a 500 cc twin, stepped piston engine called the 'Wulf'. However, as the Norton Villiers Triumph company was again in serious financial problems, development of the 'Wulf'
3550-484: The racing successes Norton was in financial difficulty. Reynolds could not make many of the highly desired Featherbed frames and customers lost interest in buying machines with the older frames. In 1953 Norton sold out to Associated Motorcycles (AMC), who owned the brands AJS , Matchless , Francis-Barnett and James . In 1962 the Norton factory in Bracebridge Street, Birmingham was closed and production
3621-482: The rights to use the name on motorcycles were owned by North American financiers. Currently it is owned by Indian motorcycle giant TVS Motor Company The business was founded in 1898 as a "fittings and parts for the two-wheel trade" manufacturer. By 1902 the company had begun manufacturing motorcycles with bought-in engines. In 1908 a Norton-built engine was added to the range. This began a long series of production of single and eventually twin-cylinder motorcycles, and
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#17328017319193692-407: The rules changed ending supercharged racing motorcycles, but even so, Les Graham won the 1949 World Championship on an unsupercharged AJS 500 cc Porcupine. In 1951 AJS development engineer Ike Hatch developed a 75.5 mm (3.0 in) bore x 78 mm (3.1 in) stroke, three valve head version of the AJS 7R making 36 bhp (27 kW). It was called the AJS 7R3, and was Ike's response to
3763-512: The stated power does not give a true picture of the engine performance because increased torque seemed to make up for the reduced horsepower. The Commando was offered in several different styles: the standard street model, a pseudo-scrambler with upswept pipes and the Interstate, packaged as a tourer. In 1972 BSA was also in financial trouble. It was given UK Government help on the condition that it merged with Norton-Villiers , and in 1973
3834-443: The time this was achieved the thermal efficiency gains were lost, and the experiment was abandoned. There is dispute as to whether the silver cylinder head went beyond feasibility-study stage. The Porcupine used "Jam-pot" shocks and Teledraulic race forks. The E90 model had an open frame. The E95, introduced in 1953, had a loop type frame with the motor mounted lower. Only four E95 Porcupines were built. Team Obsolete have restored
3905-414: The two models still made was ended and supplies dwindled. After the break-up of NVT, Poore established Norton Motors (1978) Ltd in the former NVT factory at Shenstone, Staffordshire to continue work on the rotary. They purchased all the wankel manufacturing equipment from Hercules/DKW who had stopped manufacturing wankel machines. 25 production prototypes of a dual rotor machine were built in 1979 with
3976-588: The war, with Nortons winning every year from 1947 to 1954. After the Second World War, Norton reverted to civilian motorcycle production, gradually increasing its range. A major addition in 1949 was the twin cylinder Model 7, known as the Norton Dominator , a pushrod 500 cc twin-cylinder machine designed by Bert Hopwood . Its chassis was derived from the ES2 single, with telescopic front and plunger rear suspension, and an updated version of
4047-580: Was a British motorcycle manufacturer founded by the Collier brothers as a parent company for the Matchless and AJS motorcycle companies. It later absorbed Francis-Barnett , James , and Norton before incorporation into Norton-Villiers . Henry Herbert Collier founded Matchless as a cycle company in 1878. His sons Henry (Harry) and Charles (Charlie) joined him and the name was changed to H. Collier & Sons. AJS had been bought by Matchless's owners,
4118-499: Was an export bike primarily for use as a desert racer, sold up until 1969 as the Norton P11, AJS Model 33, Matchless G15 and Norton N15 which used the Norton Atlas engine in a modified Matchless G85CS scrambler frame with AMC wheels and Teledraulic front forks. This bike was reputed to vibrate less than the Featherbed frame model. AMC singles were also sold with Norton badging in this era. Also during this period Norton developed
4189-617: Was before the Featherbed frame appeared, developed for Norton by the McCandless brothers of Belfast in January 1950, used in the legendary Manx Norton and raced by riders including Geoff Duke , John Surtees and Derek Minter . Very quickly the featherbed frame, a design that allowed the construction of a motorcycle with good mass-stiffness distribution, became a benchmark by which all other frames were judged. Norton also experimented with engine placement, and discovered that moving
4260-510: Was dropped in favour of the rotary Wankel type engine inherited from BSA . In 1974 the UK's outgoing Conservative government of Edward Heath withdrew subsidies, but the incoming Labour government of Harold Wilson restored them after the General Election . Rationalisation of the factory sites to Wolverhampton and Birmingham (BSA's Small Heath site) caused industrial disputes at Triumph's Coventry site; Triumph would go on as
4331-703: Was followed by the Spondon-framed F1 . This model was a de-tuned replica of the Norton RCW588 factory racing machine, which won many short-distance races, but had many reliability issues requiring frequent servicing, in particular changing the primary drive chain every 100 miles. In 1988 a new team was brought in to replace Brian Crighton's team, to try to improve the model and reduce some of its reliability issues. The team, headed by ex-Honda-team manager Barry Symmons, Honda engineer Chris Mehew and chassis specialist Ron Williams, were tasked with producing
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#17328017319194402-488: Was formed by James Lansdowne Norton (known as "Pa") at 320, Bradford Street, Birmingham , in 1898. In 1902 Norton began building motorcycles with French and Swiss engines. In 1907 a Norton with Peugot engine, ridden by Rem Fowler, won the twin-cylinder class in the first Isle of Man TT race, beginning a sporting tradition that went on until the 1960s. In April 1907 the Norton Manufacturing Co. moved to
4473-474: Was formed shortly afterwards under joint directorship of James Norton and Bob Shelley. Shelley's brother-in-law was tuner Dan O'Donovan, and he managed to set a significant number of records on the Norton by 1914 when the war broke out - and as competition motorcycling was largely suspended during the hostilities, these records still stood when production restarted after the war. 1914 Dan O'Donovan records set in April 1914 : On 17 July 1914 O'Donovan also took
4544-458: Was moved to AMC's Woolwich factory in south-east London. Under AMC ownership a much improved version of the Norton gearbox was developed, to be used on all the larger models of AJS, Matchless and Norton. Again, the major changes were for improved gear selection. In September 1955 a 600 cc Dominator 99 was launched. The 1946 to 1953 Long Stroke Manx Norton was 79.6 mm × 100 mm (3.1 in × 3.9 in) initially SOHC ,
4615-542: Was not the item to place under a petrol tank. The team's project, renamed NRS 588, did win the 1992 Isle of Man TT , ridden by Steve Hislop , North West 200, and Ulster Grand Prix races ridden by Robert Dunlop . Whilst in Northern Ireland, the team met Gordon Blair, an automotive engineer from Queen's University Belfast . Blair commented that the Japanese had abandoned development of the motorcycle variant of
4686-665: Was on the right. As originally designed, the E90S was to be supercharged, with the blower mounted above the gearbox, and driven by the clutch. The loss of the supercharger meant that the design was compromised, lacking sufficient flywheel effect, which caused problems with magneto failure. The main initial change was to reduce the valve angle to 90 degrees for a more compact combustion chamber. It had rubber mounted twin GP carburettors, inclined at 49 degrees, with an unusual float tank system used rather than float bowls. Plain bearings were used for
4757-662: Was reformed as Norton-Villiers , part of Manganese Bronze Holdings . The 750 Norton Atlas was noted for its vibration. Rather than change engines Norton decided to change the frame, and the isolastic-framed Norton Commando 750 was the result. In 1967 the Commando prototype was shown at the Earls Court Show in November, and introduced as a production model for 1968. Its styling, innovative isolastic frame and powerful engine made it an appealing package. The Commando easily outperformed contemporary Triumph and BSA twins and
4828-468: Was released in January 1972 with a twin roller bearing crank, 10:1 compression and developing 65 bhp (48 kW) at 6,500 rpm. Reliability immediately suffered, with frequent and early crank-shaft main-bearing failures, sometimes leading to broken crankshafts. Older engines had used one ball-bearing main bearing and one roller bearing main bearing but the Combat engine featured two roller bearings in
4899-503: Was superseded by a standard high capacity roller bearing early in 1973. In April 1973 an 8.5:1 compression 828 cc "850" engine was released with German FAG SuperBlend bearings. These, featuring slightly barrel-shaped rollers, had been introduced on late model 750 cc engines to cure the Combat engine's problems of crank-flex and the consequent digging-in to the bearing-surface of the initial cylindrical bearing rollers. This model produced 51 bhp (38 kW) at 6,250 rpm but
4970-519: Was the most powerful and best-handling British motorcycle of its day. The isolastic frame made it much smoother than the Atlas. It used rubber bushings to isolate the engine and swing arm from the frame, forks, and rider. However, as the steel-shims incorporated in the Isolastic bearings wore, often from rusting, the bike became prone to poor handling: fishtailing in high-speed turns. The "Combat" engine
5041-537: Was the only World Championship win for AJS. Despite this victory, the bike is often cited as unreliable, and not living up to its promise. The E90S Porcupine engine was a unit construction , aluminium alloy, 500 cc, DOHC twin, with horizontal cylinders and heads, to give the bike a low centre of gravity . A later version of this motor was named the E95, re-engineered to have its cylinders inclined at 45 degrees for better cooling and easier carburettor installation, and
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