Two Wheeler Components
Motorcycles are produced with both two-stroke- and
four-stroke-cycle engines and have up to four cylinders. Most of them are
air-cooled, though a few are water-cooled. Their engines are generally
limited to 1,200-cubic-centimetre (73-cubic-inch) displacements.
Mopeds The smallest designs are termed mopeds (from motor
pedal), and have very small (50 cubic centimeters) engines offering
100-miles-per-gallon fuel economy. Such units are not permitted on
limited-access public roads because of their low speed capability.
Types of motorcycles Motorcycles are classified into four
types in order of increasing power capacity and engine displacements.
They are - trail bikes, road bikes, touring bikes, and racing bikes. The
highest performance levels in racing are attained by "superbikes"
with up to 160 horsepower produced for vehicles weighing approximately
Frame The motorcycle frame is often of steel, which is usually
a combination of tubes and sheets. The wheels are generally aluminum or
steel rims with spokes, although some cast wheels are used. Graphite and
magnesium parts are increasingly in use because of high
Tyres The tyres that are used are similar to those used on
automobiles but are smaller and rounded to permit leaning to lower the
center of gravity in a turn without losing traction. Front-wheel
suspension is provided by coil springs on a telescopic fork; rear-wheel
springs are often mounted on shock absorbers similar to those used in
Transmissions Transmissions on motorcycles typically have four
to six speeds, although small bikes may have as few as two. Power is
normally transmitted to the rear-wheel sprockets by a chain, though
occasionally belts or shafts are used.