Motorcycle components

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Motorcycle components and systems for a motorcycle are engineered, manufactured, and assembled in order to produce motorcycle models with the desired performance, aesthetics, and cost. The key components of modern motorcycles are presented below.

The chassis of a motorcycle includes the frame and suspension, along with the front forks, of the vehicle.^[1]

The frame is typically made from welded

Buell motorcycles employed a similar design with the oil held in the swingarm and fuel held in the frame.

Modern designs have the two wheels of a motorcycle connected to the chassis by a suspension arrangement, however 'chopper' style motorcycles often elect to forgo rear suspension, using a rigid frame.

The front suspension is usually built into the

The rear suspension supports the swingarm, which is attached via the swingarm pivot bolt to the frame and holds the axle of the rear wheel. The rear suspension can consist of several shock arrangements:

• Dual shocks, which are placed at the far ends of the swingarm
• Traditional monoshock, which is placed at the front of the swingarm, above the swingarm pivot bolt
• Softail style suspension, where the shock absorbers are mounted horizontally in front of the swingarm, below the swingarm pivot bolt and operate in extension.

A fuel tank (also called a petrol tank or gas tank) is a safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled (fuel pump) or released (pressurized gas) into an engine.

A motorcycle fork is the portion of a motorcycle that holds the front wheel and allows one to steer. For handling, the front fork is the most critical part of a motorcycle. The combination of rake and trail determines how stable the motorcycle is.

The 'fork' on a motorcycle consists of multiple components. The triple trees (also known as yokes) hold the fork tubes (which contain the fork springs), and are fastened to the neck of the frame by the steering stem. At the bottom of the fork tubes are the lower legs, often referred to as sliders. The sliders house the dampening assemblies, which vary based on the brand and type of fork. The front axle is located perpendicular and engages the sliders.^[4] The handlebars are clamped to the top triple tree and allow the rider to steer the motorcycle.

Almost all commercially available motorcycles are driven by conventional gasoline internal combustion engines, but some small scooter-type models use an electric motor, and a very small number of diesel models exist (e.g., the USMC M1030 M1 version of the Kawasaki KLR650 and the Dutch-produced Track T-800CDI).

Motorcycle engines range from less than 50 cc (cubic centimetres), commonly found in many small scooters, to 5735 cc, a Chevrolet V8 engine, currently used by Boss Hoss in its cruiser style motorcycle.

Motorcycles have mostly, but not exclusively, been produced with one to four

Engines with more cylinders for the same displacement feel smoother to ride. Engines with fewer cylinders are cheaper, lighter, and easier to maintain. Liquid-cooled motorcycles have a radiator which is the primary way their heat is dispersed. Coolant or oil is constantly circulated between this radiator and the cylinder when the engine is running. Air-cooled motorcycles rely on air blowing past fins on the piston cylinder head and/or engine case to disperse heat. Liquid-cooled motorcycles have the potential for greater power at a given displacement, tighter tolerances, and longer operating life, whereas air-cooled motorcycles are potentially cheaper to purchase, less mechanically complex and are lighter.

An air-cooled engine contracts and expands with its wider temperature range, requiring looser tolerances, and giving shorter engine life. The temperature range of an air-cooled two-stroke is even more extreme and component life even shorter than in an air-cooled four-stroke.

As applied to motorcycles, two-stroke engines have some advantages over equivalent four-stroke engines: they are lighter, mechanically much simpler, and produce more power when operating at the high rpm power-band. But four-stroke engines are cleaner, more reliable, and deliver power over a much broader range of engine speeds. In developed countries, two-stroke road-bikes are rare, because—in addition to the reasons above—modifying them to meet contemporary emissions standards is prohibitively expensive. Almost all modern two-strokes are single-cylinder, liquid-cooled, and under 600 cc.

In November 2006, the Dutch company E.V.A. Products BV Holland announced that its diesel motorcycle, the Track T-800CDI, achieved production status.^[5] The Track T-800CDI uses an 800 cc three-cylinder Daimler Chrysler diesel engine. Other manufacturers, including Royal Enfield, had been producing diesel-powered bikes since at least the 1980s.^[6] Also, Intelligent Energy, an English alternative-fuel company, is developing a motorcycle powered by a detachable hydrogen-powered fuel cell, which it calls an Emissions Neutral Vehicle (ENV).^[7] According to reports, the vehicle can sustain speeds of 80 km/h while making virtually no noise, and can run for up to four hours without refuelling.

Most motorcycles have a

Engine power can be engaged or interrupted through the clutch, typically an arrangement of plates stacked in alternating fashion, one geared on the inside to the engine and the next geared on the outside to the transmission input shaft.

Power transfer from the gearbox to the rear wheel is accomplished by different methods.

Chain-drive uses sprockets and a roller chain, which requires both lubrication and adjustment for elongation (stretch) that occurs through wear. The lubricant is subject to being thrown off the fast-moving chain and results in grime and dirt build-up. Chains do deteriorate, and excessive wear on the front and rear sprockets can be dangerous. In a chain-drive, the power is transmitted into the rear wheel via a cush drive. Conventional roller chain-drives suffer the potential for vibration, as the effective radius of action in a chain and sprocket combination constantly changes during the revolution ("chordal action"). If a drive sprocket rotates at constant RPM, then the chain (and the driven sprocket) must accelerate and decelerate constantly. Most chain-driven motorcycles are fitted with a rubber bushed rear wheel hub to eliminate this vibration issue. Belt-drive and shaft-drive are also used.

Small budget motorcycles may have a totally enclosed drive chain, but this is rare on larger motorcycles, an exception being the Norton rotary bikes. To prevent rapid wear of the chain and sprockets, it is customary to apply an adhesive petroleum, graphite or silicon based composite chain-lube via an aerosol. Many riders also fit aftermarket chain-oilers to feed a regular supply of oil to the chain at the rear sprocket.^[8] These chain oilers vary in sophistication, but all add significantly to the life of the chain. The custom of lubing by immersing the chain in a tin of hot grease ceased in the early 1970s, once most chains had rubber "O'-rings. The original Suzuki RE5 of 1975 came with a rear chain oiler, but the 1976 model had a sealed chain, and its oiler was deleted as "unnecessary".

A

A shaft-drive is usually completely enclosed; the visual cue is a tube extending from the rear of the transmission to a bell housing on the rear wheel. Inside the bell housing a bevel gear on the shaft mates with another on the wheel mount. This arrangement is superior in terms of noise and cleanliness and is virtually maintenance-free, with the exception of occasional fluid changes. They are the most durable and usually last the life of the motorcycle. However, the additional gear sets are a source of power loss and added weight. A shaft-equipped motorcycle may also be susceptible to shaft effect.

Virtually all high-performance racing motorcycles use chain-drive because they are the most mechanically efficient transmitting power to the rear wheel.

The

At one time, motorcycles used

Motorcycles mainly use

Touring tires are usually made of a harder rubber compound for greater durability, these may last longer but tend to provide less outright grip compared to sports tires at optimal operating temperatures. Touring tires typically offer more grip at lower temperatures and can be more suited to riding in cold or winter conditions where a sport tire may never reach its optimal operating temperature.

Cruiser and sport touring tires are designed to compromise between grip and durability. These tend to have stronger sidewalls as they are typically fitted to heavier machines.

Motorsport or racing tires offer the highest of levels of grip. Due to the high temperatures at which these tires typically operate, use outside a racing environment is unsafe, typically these tires do not reach their optimum temperature which provides less than optimal grip. In racing situations, tires are normally brought up to temperature in advance based on application and conditions through the use of tire warmers.

There are generally two independent brakes on a motorcycle, one set on the front wheel and one on the rear. However, some models have "linked brakes" whereby both can be applied at the same time using only one control.

Front brakes are generally much more effective than rear brakes: roughly two thirds of stopping power comes from the front brake—mainly as a result of weight transfer being much more pronounced compared to longer or lower vehicles, because of the motorcycle's short

Brakes can either be drum or disc based, with disc brakes being more common on large, modern or more expensive motorcycles for their far superior stopping power, particularly in wet conditions. There are many brake-performance-enhancing aftermarket parts available for most motorcycles, including brake pads of varying compounds and steel-braided brake lines.

Harley-Davidson replaced drum brakes with disc brakes on Big Twin models starting in 1972, and on Sportster models starting in 1973.

In 1981, BMW introduced an

Most road motorcycles have an instrument panel, usually consisting of speedometer, odometer and tachometer.

Fuel gauges are becoming more common, but traditionally a reserve tank arrangement is used with a petcock (petrol tap) on the side of the motorcycle allowing the rider to switch to a reserve fuel supply when the main fuel supply is exhausted. There is not actually a separate reserve tank: The intake for the petcock has two pipes, one extending higher into the fuel tank than the other. When fuel no longer covers the longer pipe the engine will lose power/splutter and the rider switches the petcock to the "reserve" setting, which accesses the shorter pipe. Riders whose bikes lack a fuel gauge (most machines prior to the past few years) usually learn how far they can go with a full tank of fuel, and then use a trip meter if available to judge when they must refill the tank.

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There should be no lights and indicators for a race bike or race machine because the bike should be less in weight.

Because of safety and vehicle laws, any motorcycle that's not for racing will have some degree of a lighting system that consists of low and high beam head lamps, brake indication and running lights and turn indicators. Lighting can vary from incandescent filament lamps, gas charged lamps with halogen or argon gas filled bulbs, and in recent years, LED's. The lighting system will always function if the ignition is turned to the ON position. The low and high beam controller and the turn signal controls are usually placed on an easily operated and accessible cluster next to the hand grips. The brake light is engaged when either the front or rear brakes are applied by the use of spring loaded contacts near the front brake lever or the rear brake peddle. The lighting system uses a simple fuse box to separate the systems components and is connected to a battery. Some large touring bikes also incorporate the use of running lights or decorative accessory lights to make them more visible to other drivers at night. Some manufacturers have added a strobe effect to the headlamps to make other drivers more aware of the oncoming motorcycle. A large percentage of motorcycle accidents occur because other drivers don't see motorcycles in traffic.

An ignition switch, starter switch or start switch is a Key switch in the control system of a motor vehicle that activates the main electrical systems for the vehicle.In vehicles powered by internal combustion engines, the switch provides power to the starter solenoid and the ignition system components (including the engine control unit and ignition coil), and is frequently combined with the starter switch which activates the starter motor.

• Bicycle and motorcycle dynamics
• Shaft effect

• How Motorcycles Work by Bill Harris
• Motorcycle Glossary - definitions of motorcycle terms