The MK1 Norton Commando

The Norton Commando was the last twin piston-engined motorcycle produced by the Norton Motorcycle company.
During the 10 years it was in production it was popular all over the world. In the UK it won the MCN "Machine of the Year" competition for five successive years from 1968-1972
Some regard it as the British Motorcycle Industry's swansong, selling well from its introduction in 1967 through the end of the British bike industry as a commercial concern in the mid 1970s
The origins of the Norton Commando can be traced back from the late 1940s 497cc Norton Model 7 Twin,which was designed by Bert Hopwood.The twin cylinder design evolved into the 650 cc Norton Dominator and 750 cc Norton Atlas before being launched as the 750 cc Commando in 1967.
Mk1 750cc
The Norton Commando was introduced in 1967 at the Earls Court Show. The first production machines completed in April 1968 had bending frame problems, removed with the introduction of a new frame in January 1969. The original model, called the 'Fastback' was joined by the production racer 'S Type' which had a high level left-side exhaust and a 2.5 gallon petrol tank.
The machine was produced with parts from all over England,with the engines from Wolverhampton, frames from Manchester, while the components and final assembly was at Burrage Grove, Plumstead. In late 1968 Plumstead works was subject to a Greater London Council compulsory purchase order, and closed in July 1969. With assistance of a Government subsidy, the assembly line was moved to North Way, Andover; with the Test Department in an aircraft hangar on Thruxton Airfield. Frame manufacturing was transferred to Wolverhampton, where a second production line produced about 80 complete machines each week.
The production racer, featuring an OHV tuned engine, front disk brake and was finished in bright yellow - known as the 'Yellow Peril'. In March to June 1970 the updated S called the 'Roadster' had the 750cc OHV engine, low-level exhaust, upward angled silencers with reverse cones. September 1970 saw the introduction of the classic 'Fastback Mk2', which had alloy levers with modified stands and chain guards. The ‘Street Scrambler’ and the ‘Hi Rider’ were launched in May 1971, with the ‘Fastback Long Range’ with increased petrol tank capacity from July 1971.
The ‘Combat’ engine was introduced in January 1972 saw the appearance of the ‘Mk4 Fastback’, updated ‘Roadster’ and the ‘750 Interstate’. The ‘Combat’ delivered 65b.h.p. at 6500r.p.m. with a 10 to 1 compression ratio, but the stressed 750cc twin proved extremely unreliable, with main bearing failures and broken pistons common.
The 'Combat' engine combined with quality control problems gave the company a bad reputation, which was highly covered in the press. By the middle of 1972 BSA Triumph group were in serious financial trouble. The UK Government decided to bail the company out with a financial rescue package, providing it would agree to merge with Norton Villiers. Norton Villiers Triumph was duly formed and the new company got off to a shaky start.
Dave Burton
www.bargain-motors.com

The Sunbeam S7

The Sunbeam S7 was a British motorcycle designed by Erling Poppe.Built in Redditch, the engine layout was an unusual in-line 500 cc twin which drove a shaft drive to the rear wheel. The inline engine made this technologically feasible - horizontally-opposed ("flat") twin engine. The early S7 was expensive and over engineered, which is why it is now the most sought after and commands a premium over the S7 Deluxe and the S8, which were produced with less features to reduce costs while retaining many of the innovative parts of the early Sunbeam and updating some ideas.
Three models were produced, the S7, S7 'Deluxe' and the S8. The original S7 (the 'Tourer') (2,104 produced from 1946 to 1948) was expensive and did not sell well. In 1949 the S7 was updated to become the S7 deluxe (5,554 produced) and the S8 (8,530 produced). Both had new cylinder linings, redesigned frames and increased oil capacity.S9 and S10 models were planned but never made as BSA decided to concentrate on the more traditional twins.
Some early models of the original S7 were produced in black but most in the now familiar 'Mist Green'. The S7 Deluxe came in either 'Mist Green' or black and for export abroad BSA supplied Sunbeams in any colour.
Erling Poppe’s design was originally based on a captured BMW R75 but Sunbeam didn’t want the S series to look too ‘German’ so an in-line OHC, parallel twin was designed instead of a flat twin ‘across the frame’. Serious problems with vibration made the new Sunbeams bikes uncomfortable to ride and all production originally sent to South Africa was recalled. The excessive vibration was cured by mounting the engine on two bonded rubber engine mounts.Another problem area was the shaft drive, which had a 'worm drive' in place of the BMW bevels and tended to strip under power. Sunbeam's solution to this was to reduce the power to 24 bhp which did nothing to help post war sales.
The Sunbeam Motor Cycle Club is one of the longest established in the UK and was founded in July 1924 at the London showrooms of John Marston Ltd in Holborn Viaduct who made the Sunbeam motorcycles in their factory at Wolverhampton.The Sunbeam Motor Cycle Club is, however, a sporting motorcycle club that organises trials and vintage bike rallies and runs and the 'owners section' was just a small part of it. When Sunbeam production ended BSA sold the remaining stock of parts to Stewart Engineering. Bob and Chines Stewart were long time fans of the Sunbeam and for a time members of the Sunbeam Motorcycle Club. In 1963 they, along with other enthusiasts, broke away from the Sunbeam Motorcycle Club and formed the Sunbeam Owners Fellowship (SOF) to support owners of an S7 or S8 with any problems. A good number of Sunbeams motorcycles survive in perfect working order and many owners have been fellows of the SOF since its inception, having owned their Sunbeam since bought new or second hand in the 1960’s.

Dave Burton
www.bargain-motors.com

THE VINCENT "BLACK SHADOW"

The demand for a Sports oriented model Vincent introduced the Black Shadow . The model became so popular that the production of the Black Shadow exceeded the production numbers of the previous Rapide model. The Black Shadow was a "Stressed Frame" design. The engine, instead of being cradled in a set of frame rails, was suspended from above becoming an integral part of the structure. The Black Shadow as well as the other post Second World War Vincents featured several new technological innovations such as a unique and original alternative to the primitive telescopic front forks of the day, a sprung rear sub-frame, the extensive use of aluminium alloy and a unit construction stressed engine. It weighed in at a relatively light 458 lb which was about the weight of a pre-war 500 cc bike.
The reason for its name "Black" Shadow was due to the entire bike (including the engine) being coated with black paint. The reason for the black paint on the cylinder block is still disputed to this day. Some claim that the black paint was for looks, others claim that it had something to do with heat transfer and dissipation. Whatever the original reason behind the painting of the engine, it was very different from anything else at a time when everything was polished and chromed.

Fewer than 1,700 [2] Vincent Black Shadows were made, all hand-assembled . It is now highly prized by classic motorcycle collectors from around the world, and is valued in excess of £30,000 in today's market. In the 1960s Vincents were being sold for £100 to 3500 at then prices.

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