Revision as of 20:06, 19 September 2006 by Deanhatesyou (talk | contribs)

In general, a piston is a sliding plug that fits closely inside the bore of a cylinder .

Its purpose is to change the volume enclosed by the cylinder.

Most pistons fitted in a cylinder have piston rings. Usually there are two spring-compression rings that act as a seal between the piston and the cylinder wall. The head of the piston can be flat, bulged or otherwise shaped. Pistons can be forged or cast. The shape of the piston is normally rounded. The piston is an important component of a moped engine.