Engines: Motive Power Types: 2-stroke spark-ignition engines

Basic 2-stroke principles	In most 2-stroke gasoline engines the inlet and exhaust ports are opened and closed by the movement of the piston, not valves.
2-stroke engine power stroke	In a 2-stroke cycle there is only one revolution and one power stroke.
2-stroke engine cycle	In a 2-stroke gasoline engine, the air-fuel mixture first enters the crankcase. It then passes through the transfer port into the combustion chamber.
2-stroke intake system	In some 2-stroke gasoline engines, intake is controlled by a rotary valve in the crankshaft. Others systems use a reed valve attached to the crankcase.
2-stroke cycle	In a 2-stroke gasoline engine the events occurring below the piston are: intake of the mixture into the crankcase and its pre-compression. The events occurring above the piston are: compression of the mixture, combustion, and scavenging of exhaust gases.

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