Norton Villiers Triumph

Industry	Motorcycles
Predecessor	BSA-Triumph, Norton-Villiers
Founded	1973
Defunct	1978
Fate	Receivership
Successors	BSA Company FB-AJS Norton Motors (1978) Triumph (Meriden) Wolverhampton Industrial Engines
Key people	Dennis Poore
Brands	AJS Triumph Villiers

In 1971 the BSA Group were in financial trouble. A number of new machines had failed to sell (The BSA Beagle, Dandy and Pixie lightweights, the Triumph Tina and Ariel 3 moped. A trading loss of £3M was announced in July and 850 of the 7,000 workforce were made redundant.^[1]

To counter their falling market share due to foreign imports, BSA introduced for 1971^[2] a new 21 bike BSA/Triumph range called the 'Power Set'.^[3] The 650cc models used a new frame which was designed at Umberslade Hall, BSA's design centre that had been set up in 1968.^[4] The frame design was not completed until 3 months after production should have started.^[5] As production got underway it was found the engine on the Triumph models could not be fitted into the frame with the rocker boxes in place. Engines were hastily modified to allow the rocker boxes to be fitted once the engine was in the frame.^[6] The factories were put on unlimited overtime and night shifts were introduced to try and get production back to targets,^[7] however the delays caused BSA to largely miss the 1971 US selling season. (50% of BSAs and 85% of Triumphs were exported to the US^[3] and 90% of all motorcycle sales in the US occurred during the 3 month season^[2]). 11,000 motorcycles remained unsold in the US and had to be stored until 1972 when they were sold off heavily discounted in a 'fire sale'.^[8]

With the factories concentrating solely on manufacturing motorcycle to counter the frame delays no spares were produced. This led to an acute spares shortage in the lucrative spares market in the US.^[9]

During 1972 a number of cut-backs were made to try and improve the financial situation. Umberslade Hall, which reputedly cost BSA $2.1 million a year to run,^[4] was closed in January with the loss of 300 jobs. The Ariel 3 49 cc automatic tricycle, which had cost an estimated £2 million, was cancelled in March.^[10]

In March 1973 the British Government had approved a merger between the BSA Group and Norton Villiers.^[11]

NVT inherited three manufacturing factories at it's formation:^[a]

• Small Heath, Birmingham. Located in Armoury Road, the BSA factory had been completed in 1863.^[13] It was extensively modernised and re-equipped in 1970.^[14] It was the largest of the three factories.
• Meriden, West Midlands. The Triumph factory was built in 1942 after the original factory in Coventry was bombed during WW2.^[15]
• Wolverhampton. The Villiers factory in Marsden Road was built soon after WW1.^[16] In addition to the manufacture of Villiers engines, the factory started to produce Norton Commando engines and gearboxes in 1969.^[17] By 1973 all Commando production had been transferred to Wolverhampton.^[12]

In addition to the manufacturing plants, NVT inherited a number of other locations:

• Kitts Green, Birmingham. The BSA Group's research centre.^[18]
• Triumph No.2 Factory, Meriden. Located on the opposite side of the road to the main Meriden factory, the No.2 factory held stocks and distributed spares for non-current Triumph motorcycles.^[19]
• Andover, Hampshire. Norton's Plumstead, London factory was compulsory purchased and, with the assistance of a government subsidy, Norton moved to a newly built factory in Bridge Way, Andover in July 1969.^[20] Assembly of the Commando was transferred from Andover to Wolverhampton in May 1973. Andover becoming a final test and distribution centre.^[12]
• Thruxton, Hampshire. The Norton Villiers Performance Centre was located at the Thruxton Circuit.^[21] The AJS Stormer was also assembled here in small numbers.^[22]

Villiers set up a subsidiary company, Villiers Australia Pty Ltd, to manufacture Villiers engines in Ballarat, Australia in 1952 following the Australian Government's introduction of import restrictions on engines the previous year. As well as Villiers engines Wisconsin engines were also manufactured under licence from 1971.^[23]

In 1969 BSA/Triumph's four US distribution subsidiaries, Triumph Corporation (Tricor), Johnson Motors (JoMo), BSA-Western and BSA Inc (East) were merged into a new company BSA Corporation Incorporated (BSACI). The new company, with headquarters in Verona, Wisconsin, was made up by three subsidiary companies: Triumph Motorcycles Inc, BSA Motorcycles Inc and Top Gear (an accessory distributor). Motorcycles were distributed in the west from Duarte, California, and in the east from Tricor's former depot in Baltimore, Maryland. Top Gear's accessories were distributed from Verona.^[24] BSACI became the sole US importer of Rickman 250cc MX and 125cc Enduro and MX motorcycles in August 1971. These two strokes shared floorspace with the larger BSA and Triumph machines in BSACI dealers.^[25] The 125s used Zündapp engines and the 250s used Montesa powerplants.^[26]

Norton Villiers set up overseas subsidiary distribution companies in 1969^[27] in Australia, Canada and the US. These overseas companies were under the control of newly created Norton Villiers International. The Berliner Motor Corporation had exclusive rights to distribute Norton's in the US and after negotiations agreed to allow Norton Villiers to distribute in 7 Western States.^[28] Norton Villiers Corporation was formed and a depot was set up in Long Beach, California.^[27] Norton Villiers Canada Ltd was set up in LaSalle, Quebec and Norton Villiers Australia Pty in Punchbowl, New South Wales.

In December 1974 NVT announced turnover in the last year had increased to $24,484,000 but the company had made a loss of £3,670,000.^[29] The Trident T160 was also launched in that month. It featured forward sloping cylinders, left hand gearchange, electric start and rear disc brake.^[30]

In the financial year ending on 31 March 1975, NVT had a turnover of $85M and made a loss of $12M.^[31]

The 850 Commando MkIII was launched in April 1975 featuring an electric start, left hand gearchange and disc rear brake.^[29] In July NVT held a press reception in London. On show was the new Cosworth engine, a prototype twin rotor wankel powered machine and two new lightweights the company intended to build: a 125 cc trail bike powered by a Taiwanese engine and a 50 cc moped designed by Bob Trigg which was powered by an Italian Morini engine.^[32]

In late 1974 Peter Deverall, NVT’s Director of Overseas Planning, wrote a report assessing the viability of manufacturing motorcycles in countries that would have lower overheads than the UK and therefore better returns on investments. The countries were Iraq (project code D51), USSR (D52), Poland (D53) and Yugoslavia (D53). A bike based on the BSA B50 was proposed to be built in Iraq and one based on the Triumph Quadrant in the USSR.^[33]

In late 1971 Poore had arranged a 3 year sponsorship deal with cigarette manufacturer John Player to compete in Formula 750 races.^[34] By 1973 the team were using a Peter Williams designed semi-monocoque chassis powered by a tuned Commando engine.^[35] Williams, Dave Croxford and Mick Grant campaigned the bikes. The bike won 14 international races^[36] and a 1-2 finish in the Formula 750cc TT in 1973.^[37] Williams finished 2nd in the MCN Superbike Championship and Croxford won the British 750 cc Championship.^[38]

The 1974 bike used a compact space frame and had improved brakes but was no longer competitive against the newly introduced Yamaha TZ750,^[39] although Williams did win one race at Spa.^[40] In late August at Oulton Park, Williams had a major accident when the combined seat and tank unit became detached from the bike. The accident ended Williams racing career.^[41]

Poore had commissioned Keith Duckworth of Cosworth Engineering to design a new engine to replace the aging Commando engine, the P86 Challenge. The engine was essentially two cylinders from Cosworth's world championship winning V8 DFV Formula One engine. The Challenge finally made its debut at Brands Hatch in October 1975 ridden by Croxford. In the Saturday heat Croxford was involved in a ten bike crash at the first corner. Croxford was injured in the crash and Alex George rode the bike in the Sunday race. The bike's cooling system had been damaged in the previous day's crash and the bike was retired.^[42]

In April 1976, Croxford and the Challenge were part of the British Transatlantic Trophy team. After performing poorly in the first round at Brands Hatch, the bike was withdrawn from the rest of the series. In June of that year the bike, again risen by Croxford, retired on the first lap of the Isle of Man Classic TT. Shortly after the project was cancelled.^[42]

The production racing trident Slippery Sam had been sold to racing team manager Les Williams when Triumph withdrew from racing in 1972. Williams continued to campaign the Trident with limited support from the factory.^[43] The bike won the Isle of Man Production TT in 1973, 1974 and 1975. In 1975 it was painted in NVT colours^[44] and co-ridden by works rider Dave Croxford.^[45] NVT used the bike in their advertising material that year.^[44]

In August 1975 American management consulting firm, the Boston Group, published its report on the British motorcycle industry, commissioned by the Department of Industry. The report concluded that millions of pounds would have to be injected into the industry and even it may still fail. In light of the report, Minister of Industry Eric Varley announced there would be no more aid for the industry,^[31] and that £4M of export guarantee credits were withdrawn. The American Market had slumped and NVT had around 12,000 unsold motorcycles in warehouses in the US.^[30]

Soon after Varley's announcement the Andover^[30] and Wolverhampton plants were put into receivership. 1,600 workers were made redundant at Wolverhampton, including 450 making the Villiers industrial engines.^[46] On returning from their summer break the Wolverhampton workers, led by a Senior Shop Stewards Action Committee, occupied the factory. They hoped to create a workers cooperative similar to that at Meriden.^[31] On 9th September they showed the Norton Wulf they intended to produce to the public,^[47] and in February 1976 an updated version of the Commando, the Commando 76. A consortium called the British Norton Partnership and headed by Australian oilman Ronald Titcombe and Lord Hesketh were to raise funds to buy the factory. This failed after Titcombe pulled out. An attempt to raise the required capital from Iran by ex-NVT employee also failed.^[48] The Action Committee approached Bernard Hooper, Norton's Chief Designer and designer of the Wulf to head the co-operative, which was to be funded by the worker's redundancy payments and pensions. Hooper declined as he could see no future for the project.^[49] The co-operative was never set-up,^[20] and after 8 months the sit-in ended.^[50]

NVT's debts has risen to over £5M by November 1975 and the company went into receivership. There were enough components in the Wolverhampton factory to build 1,500 Commandos. Poore negotiated with the receiver for these bikes to be built.^[51] Following discussions between NVT, the DTI, the receiver and Barclays Bank, a new subsidiary company was set up, NVT Motorcycles Ltd, with a loan of £500,000 from the British Government and Barclays Bank. The new company was to market Tridents, Commandos and Meriden made Bonnevilles through the existing dealer networks. They would also continue the development of new models and assemble the new East Rider mopeds, and be based at Shenstone, Staffordshire. A second subsidiary company was also set up, NVT Engineering Ltd, to manufacture spares in Montgomery Street, Birmingham.^[52]

Andover had been closed but was reopened as a spares depot to supply spares for both the Commandos still being built and for previously sold bikes. All the remaining spares were transferred from Wolverhampton to Andover.^[51]

Development of the Cosworth continued at the NV Performance Shop at Thruxton Circuit.^[51]

The final part of NVT, NVT Motorcycles Ltd, was liquidated in May 1978.^[53]

The AJS subsidiary of Norton has produced small numbers of a scrambles motorcycle, the AJS Stormer, at the Andover race shop. In 1974, development engineer David 'Fluff' Brown brought all of the existing components and the rights to build the Stormer. He set up a new company, FB-AJS, to build the machines in a workshop at Goodworth Clatford near Andover.^[22]

Former managing director of Villiers, David Sankey, and financial specialist Mark Scutt brought the Villiers engine concern from the receiver with help from the Department of Industry in 1976. The deal included half of the Wolverhampton factory and the machine tools to produce the engines. As the former Villiers marketing company, Villiers Engines Ltd, was still in existence, the new company was named Wolverhampton Industrial Engines.^[54][b]

In September 1975 the Triumph importer for Denmark, Busder Reinhardt, brought the Triumph No2 factory from the receiver of NVT Manufacturing Ltd complete with it's stock of spares. He formed P S Motors with Jack Shortland, the former Triumph spares manager, and Brenda Price, the company secretary of the Meriden Cooperative, as directors.^[19][55]

A consortium including Poore, Bertie Goodman and Bill Colquhoun brought the BSA name from the NVT liquidators and formed the BSA Company. The company assembled 2 stroke engined mopeds using Franco Morini engines and Italian cycle parts, marketing them under the BSA brand as the Beacer, Brigand and GT50. Updated versions of the Yamaha powered 125/175 cc NVT Rambler were produced as the BSA Tracker.^[56][57][58]

Poore also formed Norton Motors (1978) Ltd which continued development of a rotary engined bike at Shenstone.^[59][60]

Norton Villiers Australia Pty. Ltd was sold to Australian shareholders in 1978. The company continued manufacturing engines for a year and then became the sole Australian distributors of Mitsubishi stationary engines.^[23]

Andover Norton continued to supply spares after the liquidation of NVT.^[61]

The Meriden Cooperative continued to manufacture Triumph twins until it's liquidation in 1983.^[62]

At the time of the formation of NVT Norton Villiers were manufacturing the Commando and AJS Stormer. Triumph had just started production of their 1974 models, which consisted of 500cc Daytona, Adventurer, Avenger, 650cc Bonneville, 750cc Bonneville and Tiger. Production continued until the Meriden sit-in starting September 1973.

Around 50 machines were built.^[63]

Easy Rider was the name given to a number of mopeds produced by NVT between spring 1976 and May 1976, when the company was liquidated.^[53] The frame and geometry were designed by Doug Hele, Bertie Goodman was responsible for sourcing the components and styling was by Bob Trigg. Fuel was carried in the frame.^[64]

A prototype of the Easy Rider was first shown at an NVT press conference held at the RAC Club in Pall Mall, London in July 1975.^[53]

The ER4L was introduced in spring 1976 and had a sports seat and dummy fuel tank to make it look more like a motorcycle and appeal to 16 year olds in the UK.^[c] It shared the frame and many cycle parts with the step through models.^[64]

The 500cc TR5MX Avenger off-road bike was added to the Triumph range for the 1974 model year. It was a rebadged BSA B50MX. In the US it was available with a 580cc big-bore kit developed at Duarte using a ForgedTrue piston.^[66]

In an attempt to prolong the Commando's production life by increasing it's power, Poore commissioned Piper Engineering of Ashford, Kent to produce an eight valve head. An engine with the new head was produced which Piper claimed produced 90 bhp (67 kW). The engine was examined by NVT Research Department at Kitts Green by Doug Hele, Norman Hyde and John Barton. They considered that the forked rockers and rocker posts would need redesigning to avoid breakages. They were also concerned the stiff valve springs fitted could lead to excessive camshaft wear and pushrod breakages. The engine was fitted to a bike and tested at MIRA by Barton.^[67]

The 8 valve engine was tested on a dynamometer against a racing 4 valve engine supplied by Norton's Thruxton Race Shop. Both engines produced 74 bhp (55 kW) although the 8 valve produced slightly more mid-range power.^[67]

It was planned to update the Commando to maintain sales until the road-going version of the Challenge was ready. The main upgrade for the Mark IV was the use of a single 1.75 in (44 mm) SU Carburettor. Road testing of Commandos fitted with the SU showed the engine ran more cleanly and had better fuel consumption compared to the usual Amal carbs.^[68]

Mike Oldfield carried out the styling of the bike, with a new tank, seat and side panels. The riding position was the same as the Roadster Commandos but a larger tank was fitted. A mock-up of the updated bike was made. The collapse of NVT in 1975 meant the Mark IV never reached production.^[68]

With the Norton twin engine nearing the end of it's life in 1975, fitting a Triumph triple into the Commando frame was considered.^[69] A 870 cc (53 cu in) T180 engine was fitted into a Commando Roadster at Kitts Green. Although the prototype had good speed and handling,^[69] the isolastic mounting failed to isolate the rider from vibrations.^[70]

“	The Trisolastic was never as smooth as we would have liked. Apparently the vibrations of the three cylinder were different from those of the Norton twin. We tried numerous motor insulating assemblies, without ever finding the solution	”
— Doug Hele[70]

Trisolastic is derived from tri referring to both Triumph and the 3 cylinder engine, and isolastic from the Commando's rubber mounting system.^[71] The prototype is on display at the British National Motorcycle Museum.^[69]

500 SPX

Also called	Wulf
Engine	497 cc (30.3 cu in) 180° parallel twin stepped piston 2 stroke
Bore / stroke	74.5/105 x 57 mm
Top speed	103 mph (166 km/h)
Power	40 bhp (30 kW) @ 6,500 rpm
Transmission	5 speed gearbox, chain drive
Frame type	Pressed steel
Suspension	Front: telescopic Norton Roadholders Rear: Swinging arm
Brakes	Front: Single disc Rear: Drum

The 500 SPX (stepped piston cross charge),^[72] also know as the Wulf after the local Wolverhampton Wanderers football team,^[47] was a 500 cc two-stroke with stepped pistons. Instead of the usual two-stroke use of the crankcases to compress the fuel/air mix into the cylinder, the lower portion of the piston pumps the mix into the cylinder. This arrangement allows the crankshaft to be pressure lubricated, the same as a four-stroke, rather than the petrol/oil mix normally used by two-strokes. Exhaust smoke is eliminated and emissions are reduced. This also eliminates the need for needle roller bearings and a built-up crank so reducing production costs.^[72] The engine was designed to be increased to 750 cc without major modifications.^[73] A prototype was built with a pressed steel frame designed by Alec Issigonis, creator of the Mini.^[74][d]

A prototype was tested at MIRA, clocking reaching 103 mph (166 km/h).^[73] It was also tested with an SU carburettor to reduce emissions and improve fuel economy.^[76]

Design of the SPX started in 1971^[74] at Norton Villiers under chief designer Bernard Hooper, assisted by John Favill.^[72] It was part of the National Research Development Corporation (NRDC) £100,000 scheme to develop an advanced motorcycle. In 1973 NVT estimated it would cost £5 million to get the motorcycle into production.^[76] Poore shelved the project in November 1974 in favour of the wankel which would require less investment to put into production.^[77] After the closure of the Wolverhampton factory, the Stewards Action Committee unveiled the Wulf to the public as a model they would produce once a cooperative was set up.^[47]

The prototype is on display at the British National Motorcycle Museum.^[78]

BSA had started development of a Wankel motorcycle in 1968 using a 294 cc (17.9 cu in) Fitchtel and Sachs motor. In 1969 they recruited David Garside to lead the project. Garside had previously worked for Rolls-Royce developing a rotary engine and would remain in charge of the project after the formation of NVT.^[79]

Development work began on a twin rotor engine. Fitchtel and Sachs' wankel licence only covered small engines so in 1972 BSA obtained a licence to produce larger engines from NSU.^[80] The licence was had an annual fee of around £100,000 which was inherited by NVT.^[76]

In August 1974 a 588 cc (35.9 cu in) twin rotor prototype fitted in a modified P39 Bonneville frame was shown to invited members of the press at Kitts Green. The prototype was tested by The Motor Cycle and by Cook Neilson for Cycle. Both gave positive reviews and The Motor Cycle recorded a mean top speed of 119 mph (192 km/h) while testing at MIRA.^[60][81]

With Small Heath closed and with it the Trident production line, NVT Motorcycles Ltd explored the possibility of the Trident being produced at Meriden and marketed by NVT alongside the Bonneville and Tiger 750. A T160 engine was supplied to Meriden and a team led by Jim Barclay fitted the engine to a modified P39 Bonneville frame and cycle parts.^[82] The hybrid Bonneville/Trident was later displayed at the British National Motorcycle Museum.^[83]

Meriden were interested in producing the larger 871 cc (53.2 cu in) T180 engine in a Bonneville frame and cycle parts as a superbike to add to their range.^[84] A T180 engine was fitted into a Bonneville frame^[85] but the cooperative were unable to raise the funding to buy the tooling for the engine from NVT.^[86]

The P92 was a prototype motorcycle using a BSA B50 engine in a P30 (BSA Fury/Triumph Bandit) frame using Norton isolastic mountings. The engine was inclined 15° forward allowing a gear linkage mechanism to run under the gearbox changing the gear change from the right side to the left. A left side gear change was required by US regulations. Tank and seat were from a Norton Commando Roadster.^[87]

With a need for new models but little money for development, NVT looked at using existing parts to create the new models. Small Heath development engineer Brian Jones produced a paper in February 1974 entitled Feasibility study on the installation of BSA B25 and/or B50 engines in a P30 type motorcycle with an isolastic mounting frame. Poore sanctioned the R&D department at Kitts Green to produce 2 prototypes. He also asked Alan Sargent at the Wolverhampton experimental workshop to produced an isolastic prototype using the B50 frame. Neither team knew of the others work until a head to head test of the prototypes was undertaken at MIRA by test rider Bob Manns.^[87]

The Kitts Green prototype was chosen and production of 15,000 units was planned for 1976, however as NVT collapsed in 1975 the model was never produced. Whilst the model was intended to be marketed as a Norton, the prototypes were badged NT (Norton Triumph).^[87]

The Quadrant, sometimes spelt Quadrent, was a 987 cc (60.2 cu in) four cylinder prototype built at Kitts Green in 1974.^[e] Poore had suggested to R&D chief Doug Hele that NVT needed a 4 cylinder machine to compete Japanese.^[90] With no funding to design a new engine Hele and his team looked at adding another cylinder to the Trident. In spare moments^[33] they effectively combined two Trident engines, each with an outer cylinder removed, into a four.^[89]

When Poore saw the prototype engine on his next visit he was surprised to see a complete engine and sanctioned fitting it into a frame.^[90] An existing factory machine, which had previously been used for an OHC Trident project,^[89] was modified to allow the engine to be fitted. To keep the drive chain inline the engine was not fitted centrally in the frame, giving an overhang on the right side.^[90] The machine was re-registered as a 1,000 machine in January 1975 and road testing undertaken. At MIRA tester Neil Coombes achieved a one-way top speed of 127.8 mph (205.7 km/h) and a mean of 122.2 mph (196.7 km/h). The handing of the machine was found to be good.^[30] MotorCycle’s Bob Currie also tested the machine.^[90]

A feasibility study found that the engine would be complicated to build and estimated the engine would cost £50 more than the Trident engine. The Quadrant was never put into production but there was a plan to build a detuned version in the Soviet Union.^[30]

The prototype is on display at the British National Motorcycle Museum.^[30]

There had previously been attempts in 1972 to increase the capacity of the Trident for the P76 Thunderbird III (which was to form the basis for the T160 Trident). Bore was increased to 70 mm (2.8 in) which gave a capacity of 831 cc (50.7 cu in). Unresolved problems with head gaskets prevented the larger capacity engine entering production.^[91]

In 1974 a team of engineers at Kitts Green led by Norman Hyde looked again at increasing the Trident's capacity. A slightly larger bore of 68 mm (2.7 in) was combined with a longer stroke of 80 mm (3.1 in) gave a capacity of 871 cc (53.2 cu in). Stud positions were altered slightly and new, longer barrels and pushrods made. The engine used line contact rockers as used on the works racers, where valve clearances were adjusted over the pushrods not the valves. This required different rocker covers. The new engine was given the designation T180 and 3 prototype engines were made.^[30]

Prototype engine serial number T180 001 was fitted to a hybrid isolastic frame consisting of a Commando front loop and Rocket 3 rear part.^[92] It was later fitted to a modified P39 Bonneville frame by the Meriden cooperative.^[85] After the demise of NVT this engine/frame combination was displayed at the London Motorcycle Museum. When the museum closed, the engine was purchased by the Trident and Rocket 3 Owners Club (TR3OC) and built into a complete bike, replicating the porotype T180 NVT intended to build.^[93]

T180 002 was built into a standard frame by Les Williams and Steve Brown. This machine was tested in 1979 by Dave Calderwood for Bike Magazine.^[30][93][f]

The third engine which was unnumbered but commonly referred to as 003 was tuned for racing in 1975. It used a billet crankshaft, works cams and other works parts that were used on the 750 racers and produced 91.1 bhp (67.9 kW) @ 8,500 rpm. Williams and Brown built this engine into an ex-Ray Pickrell lowboy chassis. Dave Croxford rode the bike to 6th in the 1,000 cc race at the 1975 British Grand Prix at Silverstone and described it as one of the fastest bikes he had ever ridden. Development on the engine continued until Kitts Green was closed in October 1975. The engine was later purchased by Brown who had worked on it's development.^[30]

A T180 engine was fitted in a Commando to make the Commando 900 Trisolastic prototype.^[69]

After the closure of Small Heath, NVT considered building the T180 at Shenstone but as the Wankel could be hand built it would require less investment than the T180, production of the wankel was preferred.^[30] Meriden were interested in producing the T180 in a Bonneville frame to add a superbike to their range.^[84] NVT offered to sell them the tooling for the engine but the cooperative didn't have the funds. Poore applied to Eric Varley and the DTI for assistance to transfer the tooling to Meriden but the DTI weren't prepared to give any further funding.^[86]

After the liquidation of NVT Manufacturing Ltd, the Commando was no longer in production. To raise money, NVT tried to sell Yamaha Norton's isolastic system for use on their XS 650 twin which was known to have vibration problems. Yamaha Europe were positive to the idea and supplied an XS 500 as a donor bike for a prototype to be built. Paul Butler suggested that the bike be styled as an American flat tracker.^[94]

Under the guidance of Bob Trigg, co-inventor of the isolastic system, NVT stylist Mike Ofield and JPN craftsman John McLaren put together a prototype with a new, lighter frame using the isolastics. As many of the standard XS 650 as possible were retained but a new tank, seat and exhausts were fitted. The Ascot name was derived from Ascot Park racetrack in Los Angeles.^[94] (Yamaha had previously used the Ascot name in the early 1960s for a 250cc scrambler).^[95]

Yamaha in Japan declined using the isolastics on the XS 650 as the model was near the end of it's production life.^[94]

• https://www.moto-collection.org/blog/norton-du-cafe-racer-au-50-cm3/
• https://cybermotorcycle.com/gallery/norton-1975/NVT-Brochure-2.htm
• https://hansard.parliament.uk/commons/1973-06-11/debates/de8fb8b7-7b18-433b-a532-f246672a83db/NortonVilliersTriumphLimited
• https://books.google.es/books?id=ujGoDwAAQBAJ&dq=norton+Wolverhampton+closure&pg=PA149&redir_esc=y#v=onepage&q=Quadrent&f=false
• https://books.google.es/books?id=H85EDwAAQBAJ&pg=PA183&dq=tr5mx+avenger&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwjzk7zOgtCCAxWYTKQEHbOmDhUQ6AF6BAgNEAI#v=onepage&q&f=false
• https://web.archive.org/web/20170710210030/http://www.cmmilanese.it/site/1975-norton-thruxton-club-racer-750/?lang=en
• https://motorcyclerestorations.blogspot.com/2011/12/nvt125-which-bike-road-test-jun-1978.html
• https://davestestsandarticles.weebly.com/uploads/4/8/4/5/4845046/yamaha_circuit_mag_1978_1_norton_yamaha.pdf
• https://www.oldbikemart.co.uk/death-throes-once-great-industry/
• https://books.google.es/books?id=UONJDQAAQBAJ&pg=PT290&dq=ajs+stormer&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwj26v3E0O6DAxVBwQIHHS9NB_QQ6AF6BAgNEAI#v=onepage&q&f=false
• https://www.google.com/search?q=Nvt+shenstone&oq=nvt&gs_lcrp=EgZjaHJvbWUqCAgCEEUYJxg7MgkIABBFGDkYgAQyBggBEEUYOzIICAIQRRgnGDsyBggDEEUYOzIMCAQQIxgnGIAEGIoFMgcIBRAAGIAEMgcIBhAAGIAEMgcIBxAAGIAEMg8ICBAuGAoYxwEY0QMYgAQyDwgJEC4YChjHARjRAxiABNIBCTQ4NjRqMGoxNagCALACAA&sourceid=chrome&ie=UTF-8
• https://www.motorcycleclassics.com/classic-british-motorcycles/blacksidedown-last-norton-commando-sold/
• https://web.archive.org/web/20090129201414/https://www.telegraph.co.uk/motoring/motorbikes/2745293/Norton-that-lost-its-pull.html
• https://www.google.com/search?q=norton+commando+shenstone&oq=norton+commando+shenstone&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIGCAEQRRhAMggIAhAAGBYYHtIBCjE3OTYyajBqMTWoAgCwAgA&sourceid=chrome&ie=UTF-8
• https://andover-norton.co.uk/en/our-bikes/detail/291
• https://web.archive.org/web/20150209184614/http://www.gulfnortonstreamliner.com/history.html
• https://motorbikemad.com/blogs/press/1974-1700cc-gulf-norton-271mph-at-bonneville
• http://workingatamc.london/images/design_tony_denniss/article_norton_rotary.pdf

Project Numbers

Project	BSA	Norton	Triumph
P1			750 cc triple[1]
P2			Updated P1 750 cc triple, later developed into the BSA Rocket 3/Triumph Trident as P40[1]
P10		800 cc DOHC twin[2]
P11		Norton P11/Ranger - Atlas engine in Matchless frame.[3]
P22	Ariel 3 moped[4]
P25	Updated 175 cc BSA Bantam designated D18[4]
P30	350 cc DOHC twin BSA Fury[4]		350 cc DOHC Triumph Bandit[4]
P31			650 cc DOHC twin based on the existing pushrod engine[1]
P34	250/500 cc oil in frame B25/B500 singles[4]		250 cc oil in frame T25 single[4]
P36			Updated 500 cc Daytona/Trophy[4]
P39	Oil in frame 650 cc twins[4]		Oil in frame 650 cc twins[4]
P40	A75 Rocket 3 750 cc triple[4]		T150 Trident 750 cc triple[4]
P40/13	Vetter designed Rocket 3 chopper[4]		Vetter designed X-75 Hurricane[4]
P55	350 cc 4 valve single[5]
P76			Thunderbird III 831 cc overbored Trident.[1]
P92		BSA B50 500 cc engine in modified P30 Fury/Bandit frame using isolastic mounts[6]
Z26		Updated P10[2]