| 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 use a reed valve attached to the crankcase. |
| 2-stroke cycle |
Events occurring below the piston: intake of the mixture into the crankcase and its pre-compression. Events occurring above the piston: Compression of the mixture, combustion, and scavenging of exhaust gases. |
