A motorcycle, often called a motorbike, bike, cycle, or (if three-wheeled) trike, is a two- or three-wheeled motor vehicle. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising, sport (including racing), and off-road riding. Motorcycling is riding a motorcycle and being involved in other related social activity such as joining a motorcycle club and attending motorcycle rallies. There are three major types of motorcycle: street, off-road, and dual purpose. Within these types, there are many sub-types of motorcycles for different purposes. There is often a racing counterpart to each type, such as road racing and street bikes, or motocross including dirt bikes. Street bikes include cruisers, sportbikes, scooters and mopeds, and many other types. Off-road motorcycles include many types designed for dirt-oriented racing, including many series, such as B series, K series, G series and H series, which are not legal on the street in most areas. Dual purpose machines like the dual-sport style are made to go off-road but include features to make them legal and comfortable on the street as well. Each configuration offers either specialised advantage or broad capability, and each design creates a different riding posture. In some countries the use of pillions (rear seats) is restricted.
Motorcycle construction is the engineering, manufacturing, and assembly of components and systems for a motorcycle which results in the performance, cost, and aesthetics desired by the designer. With some exceptions, construction of modern mass-produced motorcycles has standardised on a steel or aluminium frame, telescopic forks holding the front wheel, and disc brakes. Some other body parts, designed for either aesthetic or performance reasons may be added. A petrol-powered engine typically consisting of between one and four cylinders (and less commonly, up to eight cylinders) coupled to a manual five- or six-speed sequential transmission drives the swingarm-mounted rear wheel by a chain, driveshaft, or belt. The repair can be done using a Motorcycle lift. Motorcycle fuel economy varies greatly with engine displacement and riding style. A streamlined, fully faired Matzu Matsuzawa Honda XL125 achieved 470 mpgUS (0.50 L/100 km; 560 mpgimp) in the Craig Vetter Fuel Economy Challenge "on real highways in real conditions". Due to low engine displacements (100200 cc (6.112.2 cu in)), and high power-to-mass ratios, motorcycles offer good fuel economy. Under conditions of fuel scarcity like 1950s Britain and modern developing nations, motorcycles claim large shares of the vehicle market. In the United States, the average motorcycle fuel economy is 44 miles per US gallon (19 km per liter).