The BSA Bantam D1

The BSA Bantam was a two-stroke motorcycle that was produced by BSA from 1948 to 1971,which was made in Birmingham England.In which overr 250,000 were sold.
The design of the Bantam was a near copy of the DKW RT 125 a German made motorbike.This original Bantam, the D1's were available only in all-over "mist green", and sold for £60 plus tax. Later models changed distinctly from the original; over the years it gained improved suspension including a rear swinging arm, electrics and the engine size increased from 125 cc to 175 cc.
The engine is a unit construction (engine and gearbox of one piece) single cylinder 2 stroke. The barrel is cast iron while the head is alloy. The gearbox was initially three speeds,. The electrics run by a magneto was on a composite assembly sitting within the flywheel with its magnet inserts; windings gave power either directly to the lights (with a dry cell for when the engine was stopped) or through a rectifier into a lead acid battery. The early D1s had a flattened fish tail style exhaust.

Dave Burton
www.bargain-motors.com

Rudge-Whitworth History

From its foundation in 1894 the Rudge Whitworth company built a reputation for quality, reliability, sporting prowess and innovation with many patented ideas reaching the production machines.
The famous 'Multi' introduced in 1912 with its variable gear ratios quickly became a sought after machine breaking many records and providing the company with their first TT win in 1914.It also saw the introduction of an in-house manufactured 4 speed gear box and the first four valve cylinder head on a 350cc which produced more power than the 500cc it replaced!
Coupled brakes using a linking cable appeared in 1925 and remained a feature until production ceased. They were also noted for their massive 8" diameter brakes which appeared for the first time in 1928.
The famous 'Ulster', which quickly became synonmous with the Rudge name, was introduced in 1929 following the Ulster Grand Prix win by Graham Walker at over 80 mph.
The Golden year of 1930 saw the junior TT 1, 2, 3 win using the newly untried fully radial 350cc 4 valve engines and the following year saw the first road machine with the fully radial valve layout.
The 'semi-radial' aluminium bronze cylinder head appeared on a road machine in 1934 and development in this engine area continued resulting in full enclosure of the valve gear from 1937 onwards.
In the final year of manufacture in 1939, the cylinder head was cast from RR50 light alloy with iron valve seat inserts. Although production ceased in December 1939.

Dave Burton
www.bargain-motors.com

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