motorcycle(redirected from Dirtbikes)
Also found in: Dictionary, Thesaurus, Medical.
motorcycle,motor vehicle whose design is based on the bicycle. The German inventor Gottlieb DaimlerDaimler, Gottlieb
, 1834–1900, German engineer, inventor, and pioneer automobile manufacturer. His improvements in the internal-combustion engine, made in the 1880s, contributed largely to the development of the automobile industry.
..... Click the link for more information. is generally credited with building the first practical motorcycle in 1885. The motorcycle did not become dependable and popular, however, until after 1900. The typical motorcycle has an air-cooled engine supported in a metal frame between two wheels. Sometimes a third wheel is added to support an open carriage, called a sidecar, which is attached to the motorcycle. The motor is a two- or four-cycle gasoline engine with one to four cylinders. Its piston displacement generally ranges from 50 to 1,500 cc. Although the motorcycle is not as safe a vehicle as the automobile, its convenience and economy have made it very popular; it is widely used for pleasure riding, racing, and commercial transportation of light goods. Modern touring motorcycles provide automatic transmission, stereo sound, and luggage space. Motorcycles are widely used by the police for traffic patrols. Use of the motorcycle has increased greatly in recent years as a result of the development of the inexpensive, lightweight motorcycle, manufactured chiefly in Asia. Dirt bikes, motorcycles specially designed and outfitted for off-road use, are also now common. The motor scooter, a variation on the motorcycle, has smaller wheels and has most of its working parts enclosed by a shield. The driver sits on a seat with his or her feet on a wide metal platform behind the front shield. Another variation on the motorcycle is the moped, a bicycle to which a small (under 50 cc) auxiliary engine has been attached. Motorcycle racing is done both on paved and unpaved surfaces, over closed and cross-country courses, for a variety of vehicle classes. Particularly popular is motocross, in which dirt bikes are raced over an off-road closed course with numerous turns, jumps, hills, and other irregular terrain.
a two-wheeled or three-wheeled (tricycle) vehicle with an internal-combustion engine having a displacement of more than 49.8 cu cm. The first motorcycles appeared in Western Europe in the late 19th century. Between 1924 and 1932 experimental models were developed and tested in Moscow, Izhevsk, and Leningrad (the Soiuz, IZh-1, IZh-2, IZh-3, IZh-4, IZh-5, and NATI-750). Serial production was begun in Leningrad in 1933 (model L-300: piston displacement, 300 cu cm; power, 4.7 kilowatts [kW]) and Izhevsk (model IZh-7, which is similar to the L-300).
Motorcycles are classified according to purpose as touring (transportation), sports, and special-purpose types. Touring motorcycles (Tables 1 and 2), which are small and light, have good maneuverability and excellent rough-road performance, and are simple to maintain, are used for personal transportation. The special-purpose types include patrol, escort, and commercial motorcycles.
A motorcycle consists of several groups of mechanisms: the engine, the power train (transmission), the running gear (undercarriage), and the electrical system. The engine is a two- or
|Table 1. Specifications of touring motorcycles produced in the USSR|
|M-106||Voskhod-2||Planeta-3||IZh lupiter-3||Ural-31 M-66||Dnepr1 MT-9|
|1Manufactured only with sidecar 2For motorcycles with sidecars 3One speed in reverse|
|Engine displacement (cu cm)..........||123.5||173.7||346||347||649||649|
|Number of cylinders (number of cycles)..........||1 (2)||1 (2)||1 (2)||2 (2)||2 (4)||2 (4)|
|Cylinder bore (mm)..........||52||61.75||72||61.75||78||78|
|Piston stroke (mm)..........||58||58||85||58||68||68|
|Maximum power, kW (hp)..........||6.62 (9)||8.1 (11)||13.2 (18)||18.4 (25)||23.6 (32)||23.6 (32)|
|Engine speed at maximum power (rpm)..........||5,200||5,400||5,000||5,400||5,000||5,200|
|Maximum speed (km/hr)..........||85||95||110||120 (90)2||105||100|
|Number of speeds..........||4||4||4||4||4||43|
|Empty weight (kg)..........||100||112||156||158 (253)2||320||320|
|Standard fuel consumption (1/100 km; speed in km/hr shown in parentheses)..........||2.75 (50)||2.8 (50)||3.55 (55)||3.75 (55)2 (5.8) 2||5.8 (55)||5.8 (55)|
|Table 2. Specifications of some foreign-made touring motorcycles|
|JAWA 50 (ČSSR)||Motobecan D125 (France)||ČZ 175 (ČSSR)||MZ250 (GDR)||Pannonia P20 (Hungary)||Kawasaki 305S2 (Japan)||BMW P60/5 (FRG)||Honda SV750 (Japan)||Munch TTS (FRG)|
|Engine displacement (cu cm)..........||48||124||172||249||246||346||599||736||1,200|
|Number of cylinders..........||1||2||1||1||2||2||2||4||4|
|Number of cycles..........||2||2||2||2||2||2||4||4||4|
|Cylinder bore (mm)..........||58||43||58||70||56||53||7.35||61||75|
|Piston stroke (mm)..........||65||43||65||65||50||5.23||7.09||63||66.6|
|Maximum power, kW (hp)..........||2.9(4)||11.04(15)||11.04(15)||13.9(19)||16.9(23)||33.2(45)||29.4(40)||49.2(67)||64.8(88)|
|Engine speed at maximum power (rpm)..........||6,500||7,000||5,600||5,500||7,500||8,000||6,400||8,500||6,500|
|Maximum speed (km/hr)...........||60||120||115||130||130||170||165||200||215|
|Number of speeds.............||3||5||4||4||5||5||4||5||4|
four-cycle carbureter type, which is cooled by the airstream (some sports and high-performance touring motorcycles are water-cooled). The power per liter of displacement for two-cycle engines of touring motorcycles is 51.5–98.2 kW/I (70–130 hp/l ); for four-cycle engines, 37–66 kW/l (50–90 hp/l ); and for sports motorcycles, 146–220 kW/l (200–300 hp/l ). The power train consists of a clutch, a gearbox, a front (motor) transmission, and a rear (main) transmission. The clutch is of the single-disk or multidisk type (the latter type is used on most motorcycles). The gearbox has two to six speeds, with four in most touring motorcycles. The front transmission (from the engine to the gearbox) is of the chain type or, less frequently, of the pinion type. The rear transmission (from the gearbox to the rear wheel) is of the chain type (sometimes a propeller shaft). The electrical equipment includes a power source (AC or DC generators and storage batteries), an ignition system, a light system (headlights and taillights), and a signal system (turn, brake, and horn signals).
In the USSR, motorcycles are produced in Minsk (displacement, 125 cu cm), Kovrov (displacement, 175 cu cm), Izhevsk (one- and two-cylinder types with a piston displacement of 350 cu cm), and Kiev and Irbit (displacement, 650 cu cm). The output of motorcycles and motor scooters in the USSR was 533,000 in 1960,711,000 in 1965, 833,000 in 1970, and 1,022,000 in 1973. In terms of combined production of motorcycles, motor scooters, and motor bicycles, the USSR is second in the world (more than 1.5 million per year); production in Japan is about 3.5 million (1973).
REFERENCESAbrosimov, A. A., and A. A. Tarbov. Mototsikly K-750, M-61, M-62. Moscow, 1962.
Zabelin, V. A., and M. P. Isaev. Izhevskie dorozhnye mototsikly, 2nd ed. Izhevsk, 1964.
Mototsikly K-125, K-175 i ikh modifikatsii. 2nd ed. Moscow, 1966. Mototsikl. Moscow, 1971.
Gintsburg, M. G. Ustroistvo i obsluzhivanie mototsiklov, 4th ed. Moscow, 1972.
S. Iu. IVANITSKII and B. V. SINEL’NIKOV
What does it mean when you dream about a motorcycle?
Unless we regularly ride one, motorcycles in dreams often represent youthful energy and/or adolescent rebelliousness. A sense of freedom and/or a sense of danger.