Differences Between Four-Stroke and Two-Stroke Engines

Four-Stroke Engine
Four-Stroke Engine
Two-Stroke Engine
Two-Stroke Engine
Feature Four-Stroke Engine Two-Stroke Engine
Power Stroke One power stroke per two crankshaft revolutions One power stroke per crankshaft revolution
Flywheel and Balance Requires heavier flywheel; less balanced Requires lighter flywheel; more balanced
Engine Weight Heavier engine Lighter engine
Design Complexity More complex due to valves Simpler, no valves (uses ports)
Cost Higher cost Lower cost
Efficiency Less mechanical efficiency due to more friction Higher mechanical efficiency, fewer moving parts
Lubrication System Complicated system; consumes less oil Simple system; consumes more oil
Usage Used in cars, buses, and trucks Used in mopeds, scooters, and motorcycles