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The Laverda 650GT is an
air cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. In all combustion engines, a great percentage of the heat ge ...
SOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
4 stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directi ...
parallel twin A straight-twin engine, also known as an inline-twin, vertical-twin, or parallel-twin, is a two-cylinder piston engine whose cylinders are arranged in a line along a common crankshaft. Straight-twin engines are primarily used in motorcycles; ot ...
motorcycle produced by the Italian manufacturer
Laverda Laverda (''Moto Laverda S.A.S. – Dottore Francesco Laverda e fratelli'') was an Italian manufacturer of high performance motorcycles. The motorcycles in their day gained a reputation for being robust and innovative. The Laverda brand was abso ...
in 1968. Only around 50 machines were produced before it was superseded by an enlarged 750 cc version. The engine design drew heavily from the
Honda CB77 The Honda CB77, or Super Hawk, is a straight-twin motorcycle produced from 1961 until 1967. It is remembered today as Honda's first sport bike. It is a landmark model in Honda's advances in Western motorcycle markets of the 1960s, noted for its ...
.


History

Laverda's production was of small capacity
singles Singles are people not in a committed relationship. Singles may also refer to: Film and television * ''Singles'' (miniseries), a 1984 Australian television series * ''Singles'' (1992 film), written and directed by Cameron Crowe * ''Singles'' ...
and twins. General manager, Massimo Laverda, visited the US in 1964 to study the market there. On his return he persuaded his father, Laverda motorcycles founder Francesco Laverda, that to succeed in the US they needed to produce a larger capacity twin. Massimo Laverda brought three motorcycles, a Honda CB77,
Norton 650SS The Norton 650SS is a vertical twin motorcycle made by Norton Motorcycle Company from 1962 to 1967. The 650SS was based on the Norton Manxman. The machine was capable of . SS stood for Sports Special. Norton discontinued its 600 cc mod ...
and a
BMW R69S The R69S, R69US, and R69 are motorcycles, fitted with 594 cc boxer twin engines, that were manufactured by BMW in Munich, Germany. Production history From 1955 to 1969, 15,347 of these 594 cc shaft-drive, opposed twin motorcycle ...
which were stripped and examined. Although the Laverda took elements from all three, the Luciano Zen designed engine was heavily based on the
Honda is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
. Bosch electrics were chosen for reliability. A prototype was shown at the November 1966 Earls Court Show in London. The engine's Honda origins being noticeable. Soon after the show the show the crankshaft phasing was changed from the original 180° to 360° to improve torque delivery. In 1967, American Jack McCormack visited the factory and rode the prototype. McCormack, who had previously worked in marketing for
Triumph The Roman triumph (Latin triumphus) was a celebration for a victorious military commander in ancient Rome. For later imitations, in life or in art, see Trionfo. Numerous later uses of the term, up to the present, are derived directly or indirectl ...
, Honda and
Suzuki is a Japan, Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, All-terrain vehicle, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs ...
in the US, intended to market Laverdas in the US under the brand. Feeling US buyers would prefer a 750 cc machine, he persuaded the factory to enlarge the twin. Laverda entered a 650 and 3 750s into the Giro d’Italia endurance race in May 1968. The 650 won its class and the 750s all finished in the top 10. Production began in May 1968 but only about 50 machines were made as the factory concentrated on the 750 cc requested by the US importer. The model was known for its quality, using quality components such as Pankl con-rods,
Ceriani Ceriani, formerly Arces, was an Italian company that designed and fabricated motorcycle frames and suspensions. The company was founded by Arturo Ceriani in 1951. Arces is an acronym derived from Arturo Ceriani S.r.l. In the European motorcycl ...
suspension, Bosch electrics and a Nippon Denso electric starter. The spine frame and Ceriani suspension gave the bike superior handling.


Technical details


Engine and transmission

The SOHC all-alloy twin engine was of
unit construction : ''For the vehicle design where the vehicle's skin is used as a load-bearing element, see Monocoque.'' Unit construction is the design of larger motorcycles where the engine and gearbox components share a single casing. This sometimes includes ...
with horizontally split
crankcase In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block. Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...
s which helped keeping the engine oil-tight. 4
main bearing Main may refer to: Geography * Main River (disambiguation) **Most commonly the Main (river) in Germany * Main, Iran, a village in Fars Province *"Spanish Main", the Caribbean coasts of mainland Spanish territories in the 16th and 17th centuries ...
s supported the
crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...
and the
big end Big or BIG may refer to: * Big, of great size or degree Film and television * ''Big'' (film), a 1988 fantasy-comedy film starring Tom Hanks * '' Big!'', a Discovery Channel television show * ''Richard Hammond's Big'', a television show present ...
s were double-row
roller bearing In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two concentric, grooved rings called races. The relative m ...
s. A duplex
chain A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A c ...
drove the camshaft and the electric starter used a single chain. A
dynamo file:DynamoElectricMachinesEndViewPartlySection USP284110.png, "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator (electric), commutator. Dynamos were the f ...
was mounted on the right end of the crank and the oil pump and points were on the left, which made a wide engine for a twin. The engine has been described as 'over-engineered' and 'unburstable'. Ignition was by points and coil with power supplied by a belt driven Bosch 150 watt
dynamo file:DynamoElectricMachinesEndViewPartlySection USP284110.png, "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator (electric), commutator. Dynamos were the f ...
. A triplex chain took power to the 7 plate
wet clutch A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
. A 5 speed
gearbox Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...
was fitted and final drive was by chain.


Cycle parts

A spine frame was used which didn't have downpipes but used the engine as a
stressed member A motorcycle frame is a motorcycle's core structure. It supports the engine, provides a location for the steering and rear suspension, and supports the rider and any passenger or luggage. Also attached to the frame are the fuel tank and battery. A ...
. Front suspension was by Ceriani
telescopic fork A telescopic fork is a form of motorcycle front suspension whose use is so common that it is virtually universal. The telescopic fork uses fork tubes and sliders which contain the springs and dampers. The main advantages of the telescopic fork ...
s and rear by
swinging arm A swingarm, or "swinging arm" (UK), originally known as a swing fork or pivoted fork, is a single or double sided mechanical device which attaches the rear wheel of a motorcycle to its body, allowing it to pivot vertically. The main component of ...
with twin
shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...
s.
Drum brake A drum brake is a brake that uses friction caused by a set of shoes or pads that press outward against a rotating cylinder-shaped part called a brake drum. The term ''drum brake'' usually means a brake in which shoes press on the inner surfac ...
s were used, the front being a 230 mm Grimeca twin leading shoe item.


References


Bibliography

* * * * * * * * {{cite magazine , last1=Saunders , first1=Andy , title=The Short Flight of the American Eagle , journal=
American Motorcyclist ''American Motorcyclist'' is an American magazine published monthly by the American Motorcyclist Association, covering issues of importance to its members, including legislation and regulations, touring, trail riding, motocross, enduros, road rac ...
, date=August 1991 , pages=16–18 , url=https://books.google.com/books?id=HvkDAAAAMBAJ&dq=laverda+750&pg=PA17 , language=en 650GT Motorcycles introduced in 1968 Standard motorcycles Motorcycles powered by straight-twin engines