Two-stroke engines offer many advantages over four-stroke engines.

• Higher power-to-weight ratio
• Higher power-to-volume ration
• Use of a variety of fuels
• Fewer working parts (no valves or camshafts)

The major disadvantage has always been emissions. Two-stroke engines are dirty. However, newer engine designs are now able to better manage emissions and offer two-stroke engines as a practical and responsible power source.

(see 2-Stroke Combustion Engine Simulation and 4-Stroke Combustion Engine Simulation)