Royal Enfield Bullet

Royal Enfield Bullet

Manufacturer	Royal Enfield (1931-1966) Royal Enfield Motors (1955–present)
Production	since 1931
Class	Standard
Engine	346 cc & 500 cc single cylinder cast-iron, lean-burn, or UCE, OHV
Transmission	4-speed Albion gearbox / 5-speed left-shift gearbox / 5-speed integrated gearbox
Wheelbase	1,370 mm (54 in)
Dimensions	L 2,120 mm (83 in) W 750 mm (30 in) H 1,080 mm (43 in)
Fuel capacity	3.5 imp gal (16 l; 4.2 US gal)

The Royal Enfield Bullet was originally a British overhead valve single cylinder four-stroke motorcycle made by Royal Enfield in Redditch, West Midlands, but now produced by Royal Enfield Motors, the successor to the British company, at Chennai, Tamil Nadu in India. The Royal Enfield Bullet has the longest production run of any motorcycle having remained continuously in production since 1948.^[1] The Bullet marque is even older, and has passed 75 years of continuous production. The Royal Enfield and Bullet names derive from the company's links with the Royal Small Arms Factory in Enfield, London.

Evolution

The Bullet has evolved from a four-valve engine with exposed valve-gear to the latest all-alloy unit construction engine with electronic fuel-injection.

1931–1939

Introduced in 1931 as a four-stroke single cylinder motorcycle, this model was the first to feature the Bullet name. It differed in a number of ways from its successors (which are now familiar): it had an inclined engine with exposed valve gear featuring four valves per cylinder with 350 cc and 500 cc options. In 1933, a 250 cc option was also added to the range.^[2] Its frame was also considerably different, having centre-spring girder front forks, being among a new range of models from Royal Enfield that featured them, along with a saddle-type fuel tank. However, common to motorcycles of this period, it had a rigid rear-end, necessitating a 'sprung' seat for the rider, which resulted in the iconic look of the motorcycle that is much replicated today, even though the sprung seat is unnecessary in modern models.

After competition success the 350 cc Royal Enfield Bullet was bought by the British Army for dispatch riders and 3,000 were also supplied to the RAF during the Second World War.

1939–1949

This model refreshed Royal Enfield's model line-up for 1939. It differed in cosmetic details, as well as in having two rocker boxes, which resulted in higher volumetric efficiency for the engine. The basic design with front girder forks was retained.

1949–1956

A number of changes were implemented in order to bring the bike up-to-date. This model featured a vertical engine with alloy head and higher compression. The frame was changed to a fully sprung design using a swing-arm with non-adjustable hydraulic shockers at the rear, while the front used a brand-new telescopic fork of Royal Enfield's own design. This enabled the introduction of a bench seat made of simple foam and with no large springs. Power transmission was via the same four-speed Albion gearbox as the previous model, with a unique 'neutral-finder' lever the rider could press from any gear other than first to shift to neutral. The crankshaft continued to have a fully floating big-end bearing. The headlight assembly was enclosed with the speedometer and ammeter into a nacelle, which also served as the attachment of the front suspension as well as the handlebars. An otherwise similar model, but with engine displacement of 499 cc, made its debut in 1953.

The prototype had done well in a performance trial and went on to win the trophy^[3] at the 1948 International Six Days Trial and two Bullet riders won gold medals.^[4] In 1952 Johnny Brittain won the Scottish Six Days Trial on a Royal Enfield Bullet and in 1953 he also won the International Six Days Trial without losing a single point.^[1]

In 1949, the Indian Army ordered Royal Enfield Bullets for border patrol use and the company decided to open a factory in Madras. In 1955, the 350 cc Bullets were sent from the Redditch factory in kit form for assembly in India, but Enfield India Ltd. soon developed the factory and produced complete motorcycles independently under licence. The 1955 model remained almost unchanged for years and Madras produced over 20,000 Bullets annually.^[2]

1956–1964

In 1955, Royal Enfield carried out some retooling and redesign at their Redditch plant, in the UK, to modernise the Bullet, and in 1959 some changes were made to the gear ratios. These changes, however, were not incorporated by the Indian arm due to its commitment to supply the Indian Army. Thus the British and Indian lines diverged, never to meet again.

Between 1956 and 1960, the British Bullet was released in several models, including a 350 cc Trials "works replica" version, a 350 cc "Clipper" model and in 1958 the Airflow version. This model had full weather protection from a large fibreglass fairing and included panniers for touring. The design was developed in partnership with British Plastics and featured as a series in The Motor Cycle magazine.^[5] The engines were the same and the only differences were in exhaust, seating, instrumentation, handlebars and fuel tank. Numerous technical improvements were also made, including moving to alternator charging (1956) and coil ignition (1960). The 350 cc model continued in production, but the 500 cc model was discontinued in 1961. In 1962, the UK company was sold and the Bullet discontinued and in 1967, the Redditch factory closed. Finally, in 1970, Royal Enfield closed down completely.^[6]

1955–1995

Enfield Bullet

Manufacturer	Enfield Ltd., India
Production	1955–1995
Successor	Royal Enfield Bullet 350/Electra/Machismo
Engine	346 cc single cylinder OHV

1995–1997

Under the newly appointed CEO of Enfield India, Siddhartha Lal, Eicher undertook major investment in the ailing firm. This was started with the purchase of trademark and intellectual property rights of the defunct British Royal Enfield firm, changing the name of the company to Royal Enfield Motors. Many management and production changes were made, with the production process being streamlined and excess capacity redistributed. Without the large-scale Army/Law Enforcement orders to bail the company out, there was only the individual sales route in which the company had to perform if it were to survive at all. The company also faced the difficult task of catering to a very diverse market. To preserve the Bullet's nature and reputation as a classic British bike, as the Raja Gaadi, and to attract youngsters away from the newly appeared performance motorcycle market, the Bullet marque was split up into two. The Bullet Standard 350 featured all the increased manufacturing quality and reliability but was maintained in the traditional 'Bullet' look, available only in black. A new model, available in more colours and chrome accents, CDI electronic ignition, and gas-charged shock absorbers - but with the same engine and gearbox as the Standard - was launched. This model was called the 'Bullet Electra'. The Electra 350 went on to become the best-selling Royal Enfield model, accounting for around half the company's sales.^{[citation needed]}

Alongside these developments, Austrian engine firm AVL was contracted to produce an all-alloy engine suitable as a drop-in replacement for the cast-iron block original engine (with design dating from 1955). The first bike with this engine was launched as the Bullet Machismo 350. This engine did not sell well in the Indian market; many prospective buyers were surveyd as saying that it didn't sound the same as the old engine, lacking the 'thump' noise of its predecessor. The engine did succeed in the Thunderbird model, a chopper style cruiser from Royal Enfield Motors. Also seen was the introduction of a disc-brake on the front wheel as a factory option domestically, and standard on exported models.

1997–2007

Ever tighter European emission norms forced the Bullet Standard 350 to end 2007 as its last model year in the EU, so when on-hand stocks were all sold the British-design engined Bullet became no longer available new. All new models exclusively featured the AVL 'lean-burn' engine. The introduction of a five-speed gearbox meant that Royal Enfield could 'fix' one of the long-standing quirks of the Bullet design—the foot-brake is on the left side while the gearshift is on the right. Accordingly, the Bullet Machismo 350 was equipped with this gearbox. However, the 'left-shift' gearchange provoked a backlash from Indian Bullet customers, forcing the company to not only continue the Bullet Standard with the traditional system, but even on the Electra it was offered only as an option, leading to the Electra four-speed (traditional) and Electra five-speed (left-shift) variants. Sales figures indicated that Indian Bullet customers had shunned the new gearbox, foregoing even the attraction of five-speed transmission to keep the gearshift traditional. However, it became standard fitment on all exported models. New developments included the addition of electric start as an option on some models, while standard on others. In 2007 and 2008, a limited edition, heavily accessorised 500 cc lean-burn Machismo 500 was produced. The Machismo 350 was discontinued.

Since 2007

Royal Enfield Bullet 350/Electra 4s/Electra 5s/Machismo 500/Classic

Manufacturer	Royal Enfield Motors, India
Production	2007–present
Engine	346 cc, 499 cc & 500 cc single cylinder cast-iron, lean-burn, or UCE, OHV

As a result of work spanning several years, a new set of engines was introduced. These were the Unit Construction Engines (UCE). The 350 cc UCE found use in the domestic model Thunderbird TwinSpark in a configuration with two sparkplugs per cylinder, with integrated 5-speed left-shift gearbox. It has not been featured on any of the Bullet models, domestic or otherwise. By 2011, the old cast-iron engine had been completely phased out, including in the Standard 350 model. Now all Royal Enfield bikes are only available with the all-aluminium UCE engine.

The 500 cc UCE features fuel injection, and has greater power than any Royal Enfield 500 cc motor. The 500 cc UCE, with an integrated five-speed gearbox, powers the current Bullet Classic model. Starting in 2009, this engine was available only in the EU to satisfy emissions regulations,^[1] but as of 2010 it is available in the United States under two frame models, the Bullet Classic C5,^[7] or the Bullet G5, which looks similar and shares paneling with the earlier AVL Electra models. In 2011 a third export model, the B5, was introduced combining the newer 500 cc UCE engine with the traditional Indian domestic tank and frame.

Custom models

Swiss motorcycle tuner Fritz W. Egli, a distributor of Royal Enfield motorcycles, was approached by a customer to create the ultimate Egli Super Bullet. The basis for this bike was Egli’s central tube frame constructed from nickel-plated chromium-molybdenum steel and the engine was completely redesigned with a longer stroke crankshaft (105 mm), special main bearings, dry clutch, timing belt primary drive. 36 mm Keihin flat-slide carburettors were added to provide an output of 40 hp (30 kW) from a 624 cc engine fed via an electric pump.^[8]

References

External links

Wikimedia Commons has media related to Royal Enfield motorcycles.

• Royal Enfield models
• Bullet 500 EFI
• Royal Enfield on the Open Directory Project