1. Cycle of Operation:

• 2-Stroke Engine: Completes a power cycle with one up and one down movement of the piston (one revolution of the crankshaft).
• 4-Stroke Engine: Completes a power cycle with two up and two down movements of the piston (two revolutions of the crankshaft).

2. Mechanical Simplicity:

• 2-Stroke Engine: Generally simpler in design, with fewer moving parts (no valves or complex valve train).
• 4-Stroke Engine: More complex, with valves, camshafts, and a more intricate valve train system.

3. Power Output:

• 2-Stroke Engine: Theoretically, for a given size, a 2-stroke engine can produce twice the power of a 4-stroke engine because it fires once every revolution instead of every other revolution. However, in practice, the difference is less pronounced due to other factors.
• 4-Stroke Engine: Generally produces more usable torque and power over a broader RPM range.

4. Fuel Efficiency:

• 2-Stroke Engine: Typically less fuel-efficient because some of the fuel-air mixture is lost during the scavenging process.
• 4-Stroke Engine: More fuel-efficient due to better control of the intake and exhaust processes.

5. Lubrication:

• 2-Stroke Engine: Lubrication is typically mixed with the fuel or injected directly into the engine. This results in the oil being burned along with the fuel.
• 4-Stroke Engine: Has a separate lubrication system with an oil sump and pump to circulate oil throughout the engine.

6. Emissions:

• 2-Stroke Engine: Generally produces higher emissions because of the loss of fuel during scavenging and the burning of oil.
• 4-Stroke Engine: Produces lower emissions due to more complete combustion and separate lubrication.

7. Maintenance:

• 2-Stroke Engine: Can be easier to maintain due to its simpler design, but may require more frequent servicing.
• 4-Stroke Engine: Generally requires less frequent servicing, but maintenance can be more complex due to the intricate valve train.