15
THE 2-STROKE ENGINE CYCLE
The 2-stroke engine differs slightly from the 4-stroke, in that it combines its phases, or strokes.
Upon initial inspection, the most noticeable difference in overall 2-stroke architecture is the
location of the INTAKE PORT.
It provides a direct feed into the CRANKCASE, and then moves into the CYLINDER via the
TRANSFER PORT. The following better describes the process.
At the beginning of the engine’s first
revolution, the piston begins an upward
motion in the cylinder, which generates
pressure in the combustion chamber, and
creates a vacuum into the CRANKCASE.
NOTE: The piston skirt is blocking the
transfer and exhaust ports, but is allowing
the air/fuel mix to enter the crankcase via
the intake port.
