Motorcycle Glossary

Cam An eccentrically shaped rotor that converts rotational movement into linear movement. Cams are used in the operation of valves, contact breaker points, and drum brakes.

Camshaft A shaft with two or more cams used in the four stroke engine to operate inlet and/or exhaust valves.

Carburettor Device that mixes fuel and air into a combustible vapour.

Chair Sidecar.

Chaps Chaps are a great clothing accessory designed for protection. They're usually made of leather and are fastened around the waist, with an open back. They snap at the ankles and zip down the legs.

Clincher Rims Type of wheel rim used with early beaded-edge tyres.

Clip-On Engine An engine that attaches to a conventional bicycle frame.

Clip-Ons Low racing handlebars that clamp directly onto the fork legs.

Compression Ratio A measurement of the difference between cylinder volume at t.d.c. and b.d.c.

Contact Breaker The spring switch in the low-tension ignition circuit that controls the timing of the spark in the high-tension circuit. Operated by a cam, contact brakers are sometimes called points.

Contracting-Band Brake A brake in which a band is tightened around a rotation drum.

Co-rider Co-rider is the name given to the passenger on the back of the motorcycle, or in a sidecar. A rider and co-rider can clearly communicate with an intercom system while in the process of riding.

Cradle Frame Frame with two tubes passing under the engine (see also open cradle frame).

Crankshaft The cranked shaft in an engine that changes the pistons linear motion into rotational motion.

Cush Drive A transmission shock absorber, usually a rubber cushion in the rear hub.

Cylinder Head A casting that caps the cylinder and contains the valves and combustion chamber.