Engine Type ( motor )

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Two stroke 

The two stroke cycle in which the sequence takes place during one revolutions of the crankshaft.The ‘strokes’ are those of the piston moving in either direction in the cylinder.There are thus one piston strokes to each revolution of the crankshaft

or

The two stroke cycle is completed in two strokes of the piston or one revolution of the crankshaft.

Four stroke

The four stroke cycle in which the sequence takes place during two revolutions of the crankshaft.The ‘strokes’ are those of the piston moving in either direction in the cylinder.There are thus two piston strokes to each revolution of the crankshaft