Motorcycle Speedway - Motorcycles

Motorcycles

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 powered 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 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.