page_title: Motorcycle speedway
section_title: Motorcycles
hierarchical_section_title: Motorcycle speedway / Motorcycles
caption_attribution_description: Deutsch: Jawa Speedway Maschine, 500ccm, 2 Ventiler, 4-Takt-Motor mir Dell'Orto Vergaser, ca. 60 PS.
context_page_description: Motorcycle speedway, usually referred to as speedway, is a motorcycle sport involving four and sometimes up to six riders competing over four anti-clockwise laps of an oval circuit. The motorcycles are specialist machines which use only one gear and have no brakes; racing takes place on a flat oval track usually consisting of dirt, loosely packed shale, or crushed rock. Competitors use this surface to slide their machines sideways, powersliding or broadsiding into the bends. On the straight sections of the track the motorcycles reach speeds of up to 70 miles per hour.
  There are now both domestic and international competitions in a number of countries including the Speedway World Cup whilst the highest overall scoring individual in the Speedway Grand Prix events is pronounced the world champion. Speedway is popular in Central and Northern Europe and to a lesser extent in Australia and North America. A variant of track racing, speedway is administered internationally by the Fédération Internationale de Motocyclisme. Domestic speedway events are regulated by FIM affiliated national motor sport federations.
context_section_description: Speedway uses a unique type of motorcycle, governed by the FIM's "Track Racing Technical Rules". In the past, bikes with upright engines were used (the name taken from the way the engine sits in the frame), but today most professional riders use laydown bikes as it is argued that they are easier to handle. As speedway bikes do not use brakes, the clutch is used as a release mechanism at the start of races. FIM regulations state that the motorcycles must have no brakes, are fueled by pure methanol, use only one gear and weigh a minimum of 77 kilograms (170 lb). By using engine and rear wheel sprockets the gear ratio can be adjusted as required for track conditions. The use of methanol allows for an increased compression ratio to the engine producing more power than other fuels and resulting in higher speeds (approximately 130 kilometres per hour (81 mph) when cornering).
  Machines used must:
  Weigh no less than 77 kg (unfuelled)
  Use a four-stroke, single-cylinder engine with one carburettor and one spark plug and a maximum displacement capacity of 500cc
  Have guards fitted over moving engine parts where reasonable
  Use an additional chain guard to prevent a hand or fingers being cut at the nip point where the chain meets the sprocket by a chain
  Have a peg (Dutch Peg) fitted to prevent a broken primary chain flailing and injuring a rider or a fellow competitor
  Use shatter resistant plastics where reasonable
  Be fitted with a dirt deflector
  Be fuelled by methanol with no additives
  Be fitted with an approved silencer
  Have a handlebar width greater than 650 mm and less than 850 mm.
  Machines used cannot:
  Be constructed in any part from Titanium
  Use uncoated ceramic parts
  Use telemetry during a race except for timing purposes
  Use any electronic components to control the engine
  Use brakes of any form
  Use supercharger or a turbocharger of any kind.
  In addition all motorcycles must have a safety cut out device fitted; this is defined as a switch that "must cut off the circuit of the electrical supply by the simple action of pulling a lanyard or a non-elastic string (with a maximum length of 30 centimetres (12 in)) attached to the rider's right wrist." The high compression ratio of the engine can also assist in slowing down a machine; if the throttle is closed the engine may stop. Riders can stop the bike by deliberately laying down the bike on the track and this technique is used to avoid riders who fall in front of a pursuing colleague. Before cut outs were fitted an engine was stopped in an emergency situation by removing the plug lead from the spark plug or shutting off the fuel supply.
caption: 1983 World Champion Egon Müller's Jawa Speedway Machine with 500 cc engine
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