Motorcycle engine - AbsoluteAstronomy.com

A motorcycle engine is an engine that powers a motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

.

Motorcycle engines may be two-stroke or four-stroke, reciprocating or Wankel

Wankel engine

The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into a rotating motion instead of using reciprocating pistons. Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that...

, single-cylinder or multicylinder (if reciprocating), or single-rotor

Suzuki RE5

The Suzuki RE5 is a motorcycle with a Wankel rotary engine that was manufactured by Suzuki from 1974 to 1976.-Notes:Suzuki's RE5 was one example of the very few Wankel engine motorcycles that were produced. Some of the others were by DKW and Norton Motorcycle Company, e.g. the Norton Interpol 2,...

or twin-rotor

Norton Classic

The Classic is a motorcycle built in 1987 by Norton as a special edition of just 100 machines.The Classic used an air-cooled twin-rotor Wankel engine that had been developed by David Garside at BSA...

(if Wankel). The engine typically drives the rear wheel, but some small bikes such as the Velosolex

VéloSoleX

VéloSoleX is a moped, or motorised bicycle, which was originally produced by the French manufacturer Solex, based in Paris, France. The company manufactured centrifugal radiators, carburetors, and micrometers, before branching into assist motors and bicycles...

have a friction drive to the front wheel. Most engines have a gearbox of between two and six ratios, and the Honda Gold Wing touring motorcycle

Touring motorcycle

A touring motorcycle is a type of motorcycle designed for touring. Although any motorcycle can be used to tour with, manufacturers have brought specific models designed to address the particular needs of these riders...

has a reverse gear. Power is sent to the driven wheel by belt, chain or shaft. In Europe, up till the 1970 Honda CB750

Honda CB750

The Honda CB750 is a motorcycle built in several model series between 1969 and 2003 and 2007 that is recognized as a milestone for Honda's successful introduction of a transverse, overhead camshaft inline four-cylinder engine that has ever since been the dominant sport bike configuration...

, engine capacities

Engine displacement

Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...

typically ranged from about 50 cc to 750 cc; but since then machines with capacities up to 2300 cc Triumph Rocket 3 have become common. In the USA, motorcycles with large capacities have been common for much longer.

Even today, most motorcycles still bear some resemblance to early motorised bicycles, so the engine is normally found where the crank-wheel would be on a pedal bicycle. However, some early examples like the 1921 Megola

Megola

The Megola was a German motorcycle produced between 1921 and 1925 in Munich. Like Bimota, the name is a portmanteau derived loosely from the names of its designers Meixner, Cockerell, and Landgraf.-An Unusual Design:...

and 1935 Killinger and Freund

Killinger and Freund Motorcycle

The Killinger and Freund Motorcycle was an attempt in 1935 by a group of five German engineers from Munich to design a more streamlined and modified version of the German Megola front-wheel drive motorcycle. The work took three years to complete but the result was impressive...

had the engine within the driven wheel, and the Velosolex has its engine ahead of the handlebars, just above the front wheel.

History

The first motorcycles were powered by steam engine

Steam engine

A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

s. The earliest example is the French Michaux-Perreaux steam velocipede

Michaux-Perreaux steam velocipede

The Michaux-Perreaux steam velocipede was a steam powered velocipede made in France sometime from 1867 to 1871, when a small Louis-Guillaume Perreaux commercial steam engine was attached to a Pierre Michaux manufactured iron framed pedal bicycle...

of 1868. This was followed by the American Roper steam velocipede

Roper steam velocipede

The Roper steam velocipede was a steam-powered velocipede built by inventor Sylvester H. Roper of Roxbury, Boston, Massachusetts, United States sometime from 1867–1869. It is one of three machines which have been called the first motorcycle, along with the Michaux-Perreaux steam velocipede,...

of 1869, and a number of other steam powered two and three wheelers, manufactured and sold to the public on through the early 20th century.

Using frames

Motorcycle frame

A motorcycle frame includes the head tube that holds the front fork and allows it to pivot. Some motorcycles include the engine as a load-bearing, stressed member. The rear suspension is an integral component in the design. Traditionally frames have been steel, but titanium, aluminium, magnesium,...

based both on the earlier boneshaker and the later—and in many ways completely modern—safety bicycle

Safety bicycle

A safety bicycle is a type of bicycle that became very popular beginning in the late 1880s as an alternative to the penny-farthing or ordinary and is now the most common type of bicycle. Early bicycles of this style were known as safety bicycles because they were noted for, and marketed as, being...

design, these early steam motorcycles experimented with a variety of engine placement strategies, as well as transmission

Motorcycle transmission

A motorcycle transmission is a transmission created specifically for motorcycle applications.-Manual:All manual transmission two-wheelers use a sequential gearbox. Most modern motorcycles change gears by foot lever...

and options. While today nearly every motorcycle has its engine in the center of the frame, this became standard only around 1900-1910 after nearly every possible engine location was tried. The modern scooter engine arrangement arrived in the 1940s and remains the same today.

The Otto cycle

Otto cycle

An Otto cycle is an idealized thermodynamic cycle which describes the functioning of a typical reciprocating piston engine, the thermodynamic cycle most commonly found in automobile engines....

gasoline internal combustion engine was first used on an experimental two-wheeler created by Gottlieb Daimler

Gottlieb Daimler

Gottlieb Daimler was an engineer, industrial designer and industrialist born in Schorndorf , in what is now Germany. He was a pioneer of internal-combustion engines and automobile development...

to test the practicality of such an engine in a vehicle. This motorcycle, the Daimler Reitwagen

Daimler Reitwagen

The Daimler Reitwagen or Einspur was a motor vehicle made by Gottlieb Daimler and Wilhelm Maybach in 1885, and is widely recognized as the first motorcycle. Daimler is often called "the father of the motorcycle" for this invention...

, is credited as the world's first motorcycle by many authorities, partially on the assumption that a motorcycle is defined not as any two-wheel motor vehicle, but a two-wheel internal combustion engine motor vehicle.
The Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

, for example, defines the word motorcycle this way.
The steam cycles were also simply neglected and forgotten by many historians, even as the Michaux-Perreaux waited forty years on display in the National Motor Museum, Beaulieu.

In recent years, a surge in interest in clean energy has put many new electric powered two wheelers on the market, and they are registered as motorcycles or scooters, without the type of powerplant being an issue. Diesel motorcycles were also been experimented with briefly throughout the 20th century, and are again the subject of interest due to fuel economy and the needs of military logistics. The USMC has ordered a new diesel motorcycle, the M1030 M1, that can use the same fuel, JP-8

JP-8

JP-8, or JP8 is a jet fuel, specified and used widely by the US military. It is specified by MIL-DTL-83133 and British Defence Standard 91-87, and similar to commercial aviation's Jet-A....

, as the rest of their armored vehicles, aircraft, cars and trucks.

The overwhelming majority of the motorcycles produced and used in the world today have small displacement air-cooled single-cylinder engines, both two- and four-strokes. In the wealthier parts of the world, Europe and Japan, larger displacements and multiple cylinders are common alongside small-displacement bikes required by various licensing and rider experience requirements, and so a very diverse range of sizes, cylinder numbers, configurations, and cooling systems are seen on the road. Many developed countries have graduated licensing, where a rider is licensed for a period of time to ride only smaller-displacement motorcycles before being allowed to ride larger ones. In the United States, there are no such mandates, and so the mix is skewed even further to the largest displacements, consumer demand drives manufacturers to offer their largest motorcycles to that country, and to export far fewer sub-600 cc models to the American market.

Types

Almost all production motorcycles have gasoline (UK petrol) internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s. Both four-stroke and two-stroke engines are used, but strict emission laws have led to far fewer two-strokes. A few have used Wankel rotary engines

Wankel engine

, but no Wankel bikes are currently in production. Small motorcycles are air-cooled, but oil cooling

Oil cooling

Oil cooling refers to a process whereby heat is displaced from a 'hotter' object, into a cooler oil and is the principle behind oil cooler devices. The oil carrying the displaced heat usually passes through a cooling unit such as a radiator or less commonly a gas decompresser...

or water cooling is more usual with larger machines. Some scooters use batteries and an electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

. (The 2009 TT races introduced a new category 'TTX' for electric bikes using fuel-cells or batteries).

Most motorcycle engines are mounted transversely

Transverse engine

A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the long axis of the vehicle. Many modern front wheel drive vehicles use this engine mounting configuration...

, with the crankshaft

Crankshaft

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

across the frame, but others have the crankshaft longitudinal

Longitudinal engine

In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back....

, along the frame. Transverse engines usually have chain or belt final-drive, while longitudinal mounting is more suitable for shaft final-drive.

Motor scooters

Scooter (motorcycle)

A scooter is a motorcycle with step-through frame and a platform for the operator's feet. Elements of scooter design have been present in some of the earliest motorcycles, and motorcycles identifiable as scooters have been made from 1914 or earlier...

have the engine

Swingarm

A swingarm, or "swinging arm" is the main component of the rear suspension of most modern motorcycles and ATVs...

as part of the rear suspension, so the engine not fixed rigidly to the main frame. Instead, the combined engine-transmission-swingarm assembly is pivoted to follow the road surface and is part of the "unsprung weight

Unsprung weight

In a ground vehicle with a suspension, the unsprung weight is the mass of the suspension, wheels or tracks , and other components directly connected to them, rather than supported by the suspension...

". The chain final-drive of scooters runs in an oil-bath within the engine casings. "Step-throughs"

Underbone

An underbone is a small motorcycle built on a frame consisting mostly of one large diameter tubular component.The stylistic difference between a motorcycle and an underbone is considerable and they are sometimes known as "step-throughs" or even marketed as scooters in the West.The fuel tank...

motorcycles may have a rigidly fixed engine, or may have a scooter-type arrangement.

Two-stroke and four-stroke

Two-stroke engines have fewer moving parts than four-stroke engines, and produce twice the number of power strokes; consequently, two-stroke engines are more powerful for their mass. Two-strokes offer stronger acceleration, but similar top speed compared to a four-stroke engine. They are also easier to start. Two-stroke engines have shorter life due to poorer piston lubrication, since lubrication comes from the fuel-oil mix.

Four-stroke engines are generally associated with a wider power band

Power band

The power band of an engine or electric motor refers to the range of operating speeds under which an the engine or motor is able to operate efficiently...

making for somewhat gentler power delivery, but technology such as reed valve

Reed valve

Reed valves are a type of check valve which restrict the flow of fluids to a single direction, opening and closing under changing pressure on each face...

s and exhaust power-valve systems has improved ride-ability on two-strokes. Fuel economy is also better in four-strokes due to more complete combustion of the intake charge in four-stroke engines.

Nevertheless, two-strokes have been largely replaced on motorcycles in developed nations due to their environmental disadvantages. Cylinder lubrication is necessarily total-loss and this inevitably leads to a smokey exhaust, particularly on wide throttle openings. Two-stroke-engined motorcycles continue to be made in large numbers, but mostly low-power moped

Moped

Mopeds are a type of low-powered motorcycle designed to provide economical and relatively safe transport with minimal licensing requirements.Mopeds were once all equipped with bicycle-like pedals , but moped has been increasingly applied by governments to vehicles without pedals, based on their...

s, small scooters

Scooter (motorcycle)

and step-through underbone

Underbone

s where they still compete strongly with four-strokes (including the highest-selling motorcycle of all time, the 50 cc Honda Super Cub). The major markets of two-stroke motorcycles are in developing nations

Developing country

A developing country, also known as a less-developed country, is a nation with a low level of material well-being. Since no single definition of the term developing country is recognized internationally, the levels of development may vary widely within so-called developing countries...

Cylinder heads (four-stroke)

Cylinder head design has a significant effect on the efficiency of combustion, and thence the power output of the engine. The head may be flat, in which case the combustion chamber resides within the cylinder and/or a depression in the piston crown, but usually a "dome" within the cylinder head provides most of the combustion volume. In motorcycles, valve

Poppet valve

A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...

gear tends to be side valve, overhead valve

Overhead valve

An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...

(ohv) with pushrod operation, (single) overhead cam, (s)ohc, and double overhead cam, dohc. An ohc (or dohc) cylinder head will have at least two valves per cylinder (1 inlet and 1 exhaust), but some have three (2 inlet and 1 exhaust), or four (2 inlet and 2 exhaust), or even five (3 inlet and 2 exhaust). Cylinder heads are the hottest part of the engine and require adequate cooling, typically air cooling, oil cooling

Oil cooling

or liquid cooling

Liquid cooling

Liquid cooling may refer to:* The cooling of a liquid.* The cooling of machinery or devices by convection or circulation of coolants* Liquid Cooling and Ventilation Garment, a garment worn by astronauts.* Liquid metal cooled reactor...

.

Some motorcycles such as Harley-Davidsons, Moto Guzzis and BMWs become identifiable by their cylinder-head types, namely airhead

Airhead (motorcycle)

Airheads are the traditional BMW motorcycles with a flat-twin air-cooled engine that were built from 1923 to 1995...

, panhead, oilhead

Oilhead

An oilhead is the name used for BMW motorcycle engines that advertise the use of oil cooling to transfer some of the heat from the engine to the atmosphere....

, and even knucklehead . The Ducati desmos

Desmodromic valve

A desmodromic valve is a reciprocating engine valve that is positively closed by a cam and leverage system, rather than by a more conventional spring...

head enables higher rpm to be achieved without the danger of "valve bounce".

Valve control (four-stroke)

In a side-valve engine, the valves are operated from the "underhead" cam without special valve gear. OHV engines have valves operated by pushrods. OHC and DOHC engines have overhead camshafts typically operated by chain, belt, gear train or bevel gear drive.

Honda equipped the CBR400F with REV ( described as "revolution responding type valve pausing mechanism") in 1983, This system enabled to switch over the number of valve operations per cylinder between low and medium speed revolution range and high speed revolution range. In 2002, Honda introduced HYPER VTEC

VTEC

VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...

in the VFR800 Interceptor

Honda VFR800

The Honda VFR800, also known as the Interceptor, is a motorcycle introduced by Honda in 1998. It is a successor to the VFR750F , which was preceded by the VF750.From its first sales in 1986, the VFR750F scored highly on many press reviews...

. In 2006, Kawasaki introduced VVT in the Concours 14..

Unit construction

Engines and gearboxes were originally separate items, the gearbox being driven by a "primary chain". Later designs combined the two elements into a single "unit construction". Some manufacturers, such as Norton and Enfield continued with "pre-unit" construction until recently, and Harley-Davidson still makes pre-unit engines today.

In the early 1960s, BSA and Triumph, modified their pre-unit parallel twins into unit-construction engines. The decision by Lucas to discontinue making dynamos and magnetos, and to produce only alternators and coil ignition systems, was a significant factor in forcing the redesign.

Traditionally, engines and gearboxes had separate lubrication systems with different grades of oil; but modern practice is to use the same oil for both.

Cylinders and configuration

The majority of motorcycle engines are configured as singles, parallel twins, triples, fours and sixes; and all these may be inline or transverse. Vee engines include V-twins and V-fours, and horizontally opposed engines include flat-twins, flat-fours and flat-sixes. Wankel engines are either single-rotor or twin-rotor. Bigger bikes tend to have more cylinders for smoothness and increased power. Modern singles range in capacity from 50 cc to 660 cc, twins from 175 cc to 1800 cc, triples from 380 cc to 2,300 cc, and so on.

Single

Single-cylinder engines (aka "singles" or "thumpers") have the cylinder vertical, inclined or horizontal, the last type most common in step-through

Underbone

motorcycles. Single-cylinder engines require both a larger flywheel

Flywheel

A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...

and a heavier-duty gearbox than multicylinder engines. Small singles are cheap to build and maintain and are suitable as cheap utility motorcycles.

Until the mid-1960s, road-racing machines (such as Matchless, AJS and Norton) tended to be large singles, but since then multicylinder racers have become the norm. Off-road bikes still use single-cylinder engines; but the new category of dual-sport bikes tend to use twins or triples.

Twin

Parallel-twin
Starting with Edward Turner

Edward Turner

Edward Turner was a British motorcycle designer. He was born in Camberwell in the London Borough of Southwark, on the day King Edward VII was proclaimed King....

's 1937 Triumph Speed Twin

Triumph Speed Twin

The Speed Twin 5T is a motorcycle that was made by Triumph at their Coventry factory. Edward Turner, Triumph’s Chief Designer and Managing Director, launched the Triumph Speed Twin at the 1937 National Motorcycle Show. It was a 500 cc OHV vertical twin in a lightweight frame and the first...

design, and until the mid 1970s, the parallel twin was the most common British motorcycle type. Parallel twins are usually mounted transversely, with the cylinders side by side above the crankshaft, and with exhaust pipes at the front, in the cool airstream. Longitudinal twins (aka "inline twins") include the 500 cc Sunbeam S7 and S8

Sunbeam S7 and S8

The Sunbeam S7 and S8 are British motorcycles designed by Erling Poppe based on the BMW R75 designs that were acquired by BSA at the end of World War II....

. There are three crankshaft configurations for this engine: 360°, 180°, and the newer 270°. Parallel twins usually have only two main bearings.
V-twin

In a V-twin engine the cylinders form a "V" around the crankshaft. A Vee-angle of 90°, as used by Ducati and Moto Guzzi, can give perfect primary and secondary balance, with a pleasingly irregular firing order. A lesser angle gives a more compact motor, but one which is prone to vibration, such as 42° (Indian), 45° (Harley-Davidson), 52° Honda

Honda Transalp

The Honda Transalp is the name given to the XL600V, XL650V, and XL700V series of dual-sport motorcycles manufactured in Japan by Honda since 1987. The Transalp bikes all feature a liquid-cooled, four-stroke 52° V-twin engine.- History :...

, and 60° (Aprilia). Most V-twins have a single crankpin shared by side-by-side connecting rods (so that the cylinders are slightly offset), but a variation is to have a single crankpin with "fork & blade" con-rods, to keep the cylinders in line. Non-90° V-twins may have offset crankpins to try to reduce vibration.

V-twins may be mounted either longitudinally with the cylinders protruding either side (e.g. Honda CX500 and Moto Guzzi

Moto Guzzi

Moto Guzzi is an Italian motorcycle manufacturer. It is one of seven brands owned by Piaggio.Established in 1921 in Mandello del Lario, Italy, the company is noted for its central historic role in Italy's motorcycling manufacture, its prominence worldwide in motorcycle racing, and a series of...

), or transversely,(e.g. Harley Davidson, Ducati, Hesketh, Vincent, Moto Morini and Aprilia). Transverse V-twins can raise difficulties in cooling the aft cylinder, and in siting the airbox, battery, aft carburetter, and aft exhaust pipe.
Flat twin

In a flat-twin (boxer) engine, the cylinders are horizontally opposed. The boxer has perfect primary balance, balance

Engine balance

Engine balance is the design, construction and tuning of an engine to run smoothly. Improving engine balance reduces vibration and other stresses and can improve the overall performance, efficiency, cost of ownership and reliability of the engine, as well as reducing the stress on other machinery...

only a small rocking couple, and (unlike a V-twin), regular firing intervals, producing very low vibration levels (without the use of counterbalance shafts). Such engines are usually mounted longitudinally with the cylinders protrude into the airstream, so that a flat twin can satisfactorily be air-cooled. Flats twins are made by BMW

BMW Motorrad

BMW Motorrad is the motorcycle brand of the German company BMW, part of its Corporate and Brand Development division. The current General Director of the unit is Hendrik von Kuenheim....

, Ural

IMZ-Ural

IMZ-Ural is a Russian maker of heavy sidecar motorcycles. Recently the company has developed a solo motorcycle with no sidecar.In 1940, the Soviet Union acquired the design and production techniques for BMW R 71 motorcycles and sidecars. The first M-72 model was finished in 1941...

, Harley-Davidson's WW2 "XA" model, Marusho, and historically by Douglas

Douglas (motorcycles)

Douglas was a British motorcycle manufacturer from 1907–1957 based in Kingswood, Bristol, owned by the Douglas family, and especially known for its horizontally opposed twin cylinder engined bikes and as manufacturers of speedway machines...

. The longitudinal mounting makes the flat twin highly suitable for shaft final drive, but (arguably, perversely) the Douglas Dragonfly had chain-drive.

Some early motorcycles used transversely mounted flat twin engines.
Tandem twin
The Tandem Twin where the cylinders are longitudinal, and have two cranks geared together such as Kawasaki

Kawasaki Motorcycle Corporation

Kawasaki motorycles are manufactured by the Motorcycle & Engine division of Kawasaki Heavy Industries at plants in Japan, USA, Philippines, Indonesia and Thailand. The motorcycles have been produced since 1954.-History:...

's KR250 road bike and KR250 and KR350 GP Bikes. A tandem twin is effectively a pair of geared singles, and is to be distinguished from an inline twin such as the Sunbeam S7. Tandem twins are suitable primarily for two-stroke racers.

Triple

Inline 3
Three-cylinder (aka triples) are normally mounted transversely. The British Hinckley

Hinckley

Hinckley is a town in southwest Leicestershire, England. It has a population of 43,246 . It is administered by Hinckley and Bosworth Borough Council...

Triumph factory has specialised in transverse triples, although their 2,300 cc longitudinal Rocket III

Triumph Rocket III

The Triumph Rocket III is a British three cylinder motorcycle made by the Hinckley Triumph factory and has the largest displacement engine of any mass production motorcycle , at ....

has an inline engine. Other examples are the Benelli'

Benelli (motorcycles)

Benelli is an Italian Motorcycle manufacturer owned by Chinese company Qianjiang Group. It once manufactured shotguns, although this part of the business is now a separate company.-Early history:...

"Tre"and the Yamaha XS750. The Italian firm Laverda

Laverda

Laverda was an Italian manufacturer of high performance motorcycles. The motorcycles in their day gained a reputation for being robust and innovative....

made a few 1,000 cc and 1,200 cc triples. Curiously, some Laverda Triples had 120° cranks, while some had 180° cranks (essentially three-quarters of a four). BMW

BMW Motorrad

BMW Motorrad is the motorcycle brand of the German company BMW, part of its Corporate and Brand Development division. The current General Director of the unit is Hendrik von Kuenheim....

made the K75

BMW K75

The BMW K75 was a standard motorcycle produced by BMW Motorrad from 1985 to 1995. At the time of its introduction, the K75 was BMW's cheapest motorcycle...

longitudinal 750 cc triple with the cylinders parallel to the ground. Meriden Triumph developed the 750 cc Trident, from which BSA "badge-engineered the Rocket-3.

Some triples were two-strokes. The Kawasaki triple

Kawasaki triple

The Kawasaki Triples were a range of 250 cc to 750 cc motorcycles Kawasaki exported from 1969 to 1980. The engines were air-cooled, three cylinder, two-stroke with two exhaust pipes exiting on the right side of the bike, and one on the left....

s were produced with capacities of 250, 350, 400, 500, and 750 cc in the 1970s, while Suzuki produced 380, 550, and 750 triples (the last being water-cooled). Motobecane made 350 cc and fuel-injected 500 cc triples with 3 into 4 pipes in the early seventies. Honda produced the water-cooled V-3 two-strokes MVX250 and NS400. There have been various race bike triples such as Kawasaki KR750, Suzuki TR750 transverse 3's, and Proton/Modenas KR3, Honda NS500 V-3s.

Four

Four-cylinder engines are most commonly found in a transverse-mounted inline four

Straight-4

The inline-four engine or straight-four engine is an internal combustion engine with all four cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft....

layout, although some are longitudinal (as in the earlier BMW K100

BMW K100

The BMW K100 is a family of four-cylinder 987 cc motorcycles that were manufactured by BMW from 1983 to 1992.-Background:As the 1970s came to an end, BMW faced three problems from developing its flat-twin boxer engine further:...

). V-4

V4 engine

A V4 engine is a V form engine with four cylinders and three main bearings.-Automobile use:Lancia produced several narrow-angle V4 engines from the 1920s through 1960s for cars like the Lambda, Augusta, Artena, Aprilia, Ardea, Appia, and Fulvia....

and boxer designs (as in the earlier Honda Gold Wing) have been produced. One of the more unusual designs was the Ariel Square Four

Ariel Square Four

The Square Four was an Ariel motorcycle designed by Edward Turner, who devised the Square Four engine in 1928. At this time he was looking for work, showing drawings of his engine design to motorcycle manufacturers. The engine was essentially a pair of 'across frame' OHC parallel twins joined by...

, effectively two parallel-twin engines one in front of the other in a common crankcase – it had remarkably little vibration due to the contra-rotating crankshafts.

Inline 4

Since the advent of the Honda CB750

Honda CB750

straight-four engine, straight-fours have dominated the non-cruiser street motorcycle segments. The German manufacturer Münch

Münch (motorcycles)

The Münch was a German motorcycle manufacturer.They produced between 1966 and 1980. Using a URS engine, they won the 1971 World Sidecar Championship.-Literature:...

based their motorcycles on four-cylinder car engines (e.g. Mammut 2000 has a 2.0l with a turbo and cylinder heads by Cosworth

Cosworth

Cosworth is a high performance engineering company founded in London in 1958, specialising in engines and electronics for automobile racing , mainstream automotive and defence industries...

).
Flat 4

A flat-4 or horizontally opposed-4 is a flat engine with four cylinders arranged horizontally in two banks of two cylinders on each side of a central crankcase. The pistons are usually mounted on the crankshaft such that opposing pistons move back and forth in opposite directions at the same time, somewhat like a boxing competitor punching their gloves together before a fight, which has led to it being referred to as a boxer engine.
The configuration results in inherently good balance of the reciprocating parts, a low centre of gravity, and a very short engine length.
V4
Honda uses V4 engine

V4 engine

s in the ST series

Honda ST series

The Honda ST series, also known as the Pan-European in some markets, fills the gap between touring-oriented sport motorcycles such as the CBR1000F and full-dress tourers such as the Honda Goldwing....

and VFR series

Honda VF and VFR

The VF and VFR series was a motorcycle made by Honda and had a V4 engine. The bike was also the first to utilize a Sprag clutch.-V4 engine:...

. As for two-stroke engines, there were four cylinders in the smaller classes such as Kawasaki's 125 cc KR3 square 4 and Yamaha

Yamaha Motor Company

, is a Japanese motorized vehicle-producing company. Yamaha Motor is part of Yamaha Corporation and its headquarter is located in Iwata, Shizuoka. Along with expanding Yamaha Corporation into the world's biggest piano maker, then Yamaha CEO Genichi Kawakami took Yamaha into the field of motorized...

's 250 cc RD500 V4 (RZ 500 in the US). Yamaha later raced transverse four TZ500/700/750's and virtually all the bikes in the last decade of the two-stroke GP500 era were fours (first squares then Vees) i.e. Honda, Kawasaki, Cagiva, Suzuki, Yamaha - Kawasaki also experimented with a trapezoidal four the 602S. Yamaha made the V4 RD500LC, and Suzuki the RG400 and RG500 square four road bikes.
Square 4

A square four is a U engine with two cylinders on each side. This configuration was used on the Ariel Square Four

Ariel Square Four

motorcycle from 1931 to 1959. This design was revived as a two-stroke version on some racing Suzuki

Suzuki

is a Japanese multinational corporation headquartered in Hamamatsu, Japan that specializes in manufacturing compact automobiles and 4x4 vehicles, a full range of motorcycles, all-terrain vehicles , outboard marine engines, wheelchairs and a variety of other small internal combustion engines...

models, and their subsequent road-going version the RG500

Suzuki RG500

The Suzuki RG500 "Gamma" was a motorcycle built by Suzuki between 1985 and 1987 and inspired by the 1984 Suzuki RG500 "Gamma" Grand Prix motorcycle, capitalizing on Suzuki's seven consecutive constructors title wins in the 500 cc-class. The Gamma was powered by a two stroke, rotary valve, twin...

. Although some racing success was achieved, the road bikes didn't sell in great numbers, and the design was phased out in favour of in-line, four-stroke designs, as at the time two-stroke engines were quickly being superseded by more economical, reliable, and emissions-friendly four-strokes.

Five

V5
Honda has produced five-cylinder engines for racing, the RC211V 990 cc V5. No V5 engines are currently available in commercial production motorcycles.

Just prior to their collapse, BSA planned a modular family of bike engines based around a 200 cc single. The range was to include the single, a 400 cc twin, a 600 cc triple and a 1000 cc V5. None of these motorcycles reached production.

Six

Inline 6
The 1,047 cc Honda CBX

Honda CBX

The Honda CBX1000 was introduced in 1978 as the first production motorcycle Honda had produced with an inline six-cylinder engine . The twin-cam 24-valve engine produced...

was produced from 1978 to 1982. The 1,300 cc Kawasaki KZ1300 was produced from 1979 to 1989. Benelli made the 750 cc and 900 cc the Sei from 1972 to 1978. Honda made a 250 cc straight-six GP bike. The BMW K1600GT and K1600GTL

BMW K1600

The BMW K1600GTL and K1600GT are motorcycles announced by BMW Motorrad in July 2010,and unveiled at the Intermot motorcycle show in Cologne in October 2010.The bikes went on sale in March 2011....

, which were launched in 2011, have a transverse-mounted 1,649 cc engine.

Flat 6

The six-cylinder engine is currently used by Honda

Honda

is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...

in the Rune, Valkyrie

Honda Valkyrie

The Honda Valkyrie is a motorcycle that was manufactured by Honda, from model years 1997 to 2003. It was designated GL1500C in the US market and F6C in other markets....

and Gold Wing.

V8

Galbusera

Galbusera is a vintage brand of Italian motorcycles made by Moto Galbusera & Co., in Brescia from 1934 to 1955.-History:...

built a V8 in 1938, and Moto Guzzi experimented over a period of two years with its dual-overhead-cam 500 cc V8

Moto Guzzi Grand Prix 500 cc V8

The Moto Guzzi V8, or the Otto motorcycle was designed by Giulio Cesare Carcano specifically for the Moto Guzzi Grand Prix racing team for the 1955 to 1957 seasons...

(the Otto Cylindri) in the 1950s. Some custom and one-off motorcycles use more than six cylinders. For example, the Boss Hoss

Boss Hoss

Boss Hoss is a motorcycle company, founded by Monte Warne in 1990 and based in Dyersburg, Tennessee. The company manufactures motorcycles and trikes equipped with V8 engines, produced by General Motors, and semi-automatic transmissions. By the mid-1990s, Boss Hoss was selling 300 vehicles per year...

motorcycle uses (5,700 cc, 6,000 cc and 8,200 cc) Chevy V-8 crate motors. In the 1990s Daimler-Chrysler manufactured a limited number of Tomahawk

Dodge Tomahawk

The Tomahawk was a Dodge non-street legal concept vehicle introduced at the 2003 North American International Auto Show in Detroit, Michigan. It had futuristic and unusual design, featuring the V10 SRT10 engine from the Dodge Viper. The vehicle has two front wheels and two rear wheels, making it...

concept bikes featuring a Dodge Viper's V-10 engine. Australian company Drysdale have built short runs of 750 cc V8 superbikes and 1L V8 roadgoing motorcycles, both with engines specifically developed for the purpose. No major motorcycle manufacturer has used eight or more cylinders, although Honda made the 'almost' V8 oval-piston NR750 road bike and NR500 GP bike (having eight connecting rods, for example) and Morbidelli has shown two V8 prototype road bikes, but has yet to get off the ground

Other types

Wankel rotary

Hercules (motorcycle)

Hercules (motorcycle)

Hercules was a brand of motorcycle manufactured in Germany until 1992.The Hercules Company was founded in 1886 and began producing motorcycles in 1904. It was merged with Zweirad Union after being purchased by ZF Sachs in 1963....

, Norton Commando

Norton Commando

The Norton Commando is a British motorcycle with an ohv pre-unit parallel twin engine, launched by the Norton Motorcycle company in 1967. Initially a nominal 750 cc displacement, actually , in 1973 it became an 850 cc, actually ....

, ZF Sachs

ZF Sachs

ZF Sachs AG is a German manufacturer of automotive parts, producing powertrain and suspension components. It was formerly known as Fichtel & Sachs, Mannesmann Sachs and Sachs...

, Suzuki RE5

Suzuki RE5

Oval pistons
Honda NR

Honda NR

Honda's NR V-four motorcycle engine series started in 1979 with the 500cc NR500 Grand Prix racer that used oval pistons. This was followed during the 1980s by a 750cc endurance racer version known as the NR750. The oval piston concept allowed for eight valves per cylinder which generated more...

Rotary engines

Megola

Megola

, Killinger and Freund Motorcycle

Killinger and Freund Motorcycle

Jet engines
MTT Turbine Superbike

MTT Turbine SUPERBIKE

The MTT Turbine Superbike The MTT Turbine Superbike The MTT Turbine Superbike (often styled SUPERBIKE, also known as the Y2K Turbine SUPERBIKE, is the world's second wheel-driven motorcycle powered by a turbine engine, created by Ted McIntyre of Marine Turbine Technologies Inc....

Diesel

Only very small numbers of diesel engined motorcycles have ever been built. The improved fuel efficiency is offset by the increased weight, reduced acceleration and potential difficulty of starting, at least in colder climates. Enfield India built a few from 1965 onwards but is no longer doing so. In November 2006, the Dutch

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

company E.V.A. Products BV Holland announced their first diesel-powered motorcycle, its Track T-800CDI, using an 800 cc three-cylinder Daimler Chrysler diesel engine.

Several armies are moving to an all-diesel engine fleet to reduce the fire risks of petrol and the need to provide two different fuels. This includes their despatch riders as well, encouraging the market for diesel motorcycles. Interest in biofuels is also likely to encourage future developments for small Diesels.

Diesels are also available in both two- and four-stroke versions.

Liquid

Liquid-cooled motorcycles have a radiator

Radiator (engine cooling)

Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....

(similar to the radiator on a car) which is the primary way their heat is dispersed. Coolant is constantly circulated between this radiator and the cylinders when the engine is running. While most off-road motorcycles have no radiator fan and rely on air flowing over the radiators from the forward motion of the motorcycle, many road motorcycles have a small fan attached to the radiator which is controlled by a thermostat. Some off-road motorcycles are liquid-cooled, and anti-dirt protection is attached to the radiator. The cooling effect of this fan is enough to prevent the engine overheating in most conditions, so liquid-cooled bikes are safe to use in a city, where traffic may frequently be at a standstill.

Emissions regulations and the market demand for maximum power are driving the motorcycle industry to liquid-cooling for most motorcycles. Even Harley-Davidson, a strong advocate of air-cooled motors, has begun producing a Revolution liquid-cooled engine.

Air

Most air-cooled motorcycles take advantage of air blowing past the cylinder and cylinder head while in motion to disperse heat. Frequent, sustained stationary periods may cause overheating. Some models (mostly scooters) are equipped with fans that force the air to go past the cylinder block, which solves the problem of city driving. The cylinders on air-cooled bikes are designed with fins (heat sinks) to aid in this process. Air-cooled bikes are cheaper, simpler and lighter than their water-cooled counterparts.

Oil

Some manufacturers use a hybrid cooling method where engine oil is circulated between the engine case and a small radiator. Here the oil doubles as cooling liquid, prompting the name "oil-cooling." Suzuki has produced many "oil-cooled" motorcycles. Modern BMW R-series flat-twin motorcycles, such as the R1150GS, use air and oil cooling. Polaris's Victory motorcycles use oil/air cooling exclusively.

Other components

Fuel injection

Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....

and computer engine management systems are now normal on middle range and larger motorcycles and are increasingly being incorporated onto the smaller machines, partly driven by better emission control and lower maintenance but mostly by manufacturing cost considerations. Ignition systems moved from magneto

Magneto

A magneto is a type of electrical generator.Magneto may also refer to:* Magneto , permanent magnetic alternating current rotary generator* ignition magneto, magnetos on internal combustion engines...

in the 1950s to battery-coil-contact breaker (points), and these were increasingly superseded by Capacitor Discharge Ignition

Capacitor discharge ignition

Capacitor discharge ignition or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars...

(CDI) from the 1980s. Small, single-cylinder motorcycles abandoned the flywheel magneto system with contact breakers to similar flywheel driven solid-state systems at about the same time.

Turbo and Superchargers. Superchargers (blowers) were common in the GP's, until they were banned (which didn't help the two-strokes, as pre Ernest Degners new technology, they needed the help against the four-strokes). The big four also made a turbo-ed bike, Honda made two......, mainly as an exercise in technical expertise and later discontinued for more conventional methods. Bolt on (well nearly) blowers are available to put on street bikes - and they are essential for drag bikes and land speed record streamliners etc. Most sports bikes now use some sort of 'ram-air' system where, as road speed increases, more and more air is forced through ducts in the fairing to pressurize the airbox — not to be confused with the original Ram-Air system where an air scoop/cowl was fitted to the top of the cylinder heads of Suzukis two-strokes to aid cooling.

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