Difference between revisions of "Motorcycle"

The chassis (or frame) of a motorcycle is typically made from welded aluminium or steel (or an alloy) struts, with the rear suspension being an integral component in the design. Carbon-fiber is used in a few very expensive custom frames.

A plastic or fiberglass shell, known as a ''fairing'', is placed over the frame on some models to shield the rider from the wind. Drag is the major factor that limits motorcycle speed, as it increases at the square of the velocity, with the resultant required power increasing with the ''cube'' of velocity. As can be seen from the streamlined appearance of new performance motorcycles, there is much aerodynamic technology included in the design. Unfortunately, no one has been able to overcome the effect of the turbulence caused by the spinning front wheel, which prevents the motorcycle from cutting a clean path through the air. Another problem is the fact that no designs have been discovered that can improve aerodynamic performance without unacceptably compromising the rider's ability to control the machine. In the absence of a [[fairing]] or windshield, a phenomenon known as the ''windsock effect'' occurs at speeds above 100 km/h, where the rider becomes a major source of drag and is pushed back from the handlebars, tiring the rider. However, these motorcycles still effectively push their way through the atmosphere with brute force.

[[Cabin cycle]] solved the problem of aerodynamics by isolating driver from outside air.

The wheel rims are usually steel or aluminum (generally with steel spokes and an aluminium hub) or 'mag' type cast or machined aluminum. At one time, motorcycles all used spoke wheels built up from separate components (see [[wheelbuilding]]), but, except for [[Dirtbikes]], one-piece wheels are more common now. Performance racing motorcycles often use carbon-fiber wheels, but the expense of these wheels is prohibitively high for general usage.

The [[Engine displacement|Displacement]] is defined as the total volume of air/fuel mixture an engine can draw in during one complete engine cycle. In a piston engine, this is the volume that is swept as the pistons are moved from top dead center to bottom dead center. To the layperson this is the "size" of the engine. Motorcycle engines range from 50 cc ([[cubic centimetre]]s), commonly found in many small scooters, to 2294 cc, the largest production engine currently made by Triumph for its '''[[Triumph Rocket III|Rocket III]]''' cruiser-style motorcycle.

Final drive from the gearbox to the rear wheel is typically accomplished with a chain, which requires both lubrication and adjustment for elongation (stretch) through wear. The lubricant is subject to being thrown off the fast-moving chain and results in grime and dirt buildup. Chains do deteriorate, and excessive wear on the front and rear sprockets can be dangerous. Many manufacturers offer cruiser models with final drive options of a belt or a shaft. A belt drive is still subject to stretch, but operates very quietly, cleanly, and efficiently. However, belt drives are limited in the amount of power they can transmit. The belt is frequently toothed. A shaft drive is 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 bevelled gear on the shaft mates with another on the wheel mount. This arrangement is superior in terms of noise, cleanliness, and is virtually maintenance free. However, the additional gearsets are a source of power loss and add to bike weight.

Motorcycles mainly use [[pneumatic tire]]s ('tyres' in the UK) however, in some cases with off road motorcycles, the tires are filled with a type of mousse which helps prevent punctures. Both types of tires come in many configurations, the most important characteristic of any tire being the contact patch. That is the small area that is in contact with the road surface while riding.