It is normal for the exhaust pipe to make a rattling sound after the engine is shut down. The exhaust pipe is very hot when the engine is working and will expand when heated. This noise will be caused when the temperature decreases after the engine is shut down. If there is less carbon deposit in the exhaust pipe of a new car, the sound will be clearer and more obvious, which is normal.

Motorcycle, a two or three wheeled vehicle driven by a gasoline engine and steered by the handle, is light, flexible and fast. It is widely used for patrolling, passenger and freight transportation, and also for sports equipment.

Take the working principle of four stroke engine and two-stroke engine as an example: four stroke engine is widely used. The four stroke engine means that the cylinder ignites once every four reciprocating movements of the piston. The specific working principle is as follows:


Intake: At this time, the intake valve opens, the piston moves downward, and the mixture of gasoline and air is sucked into the cylinder.

Compression: at this time, the inlet valve and exhaust valve are closed at the same time, the piston moves upward, and the mixture is compressed.

Combustion: when the mixer is compressed to the minimum, the spark plug will jump and ignite the mixed gas, and the pressure generated by combustion will push the piston down and drive the crankshaft to rotate.

Exhaust: When the piston goes down to the lowest point, the exhaust valve opens, and exhaust gas is discharged. The piston continues to go up to discharge excess exhaust gas.


The working principle of the two-stroke engine is that the piston moves up and down for two strokes and the spark plug ignites once. The intake process of the second stroke engine is completely different from that of the fourth stroke engine. The two-stroke engine needs to be compressed twice. On the second stroke engine, the mixture flows into the crankcase first and then into the cylinder. Specifically, it flows into the combustion chamber, while the mixture of the fourth stroke engine flows directly into the cylinder. The crankcase of the fourth stroke engine is used to store oil, As the crankcase of two-stroke engine is used to store mixed gas and cannot store oil, the oil used for two-stroke engine is non recyclable combustion oil.

The working process of the second stroke engine is as follows:


The piston moves upward and the mixed air flows into the crankcase.

The piston descends to deliver the mixed air pressure to the combustion chamber, completing the first compression.

After the mixture reaches the cylinder, the piston goes up and closes the inlet and outlet. When the piston compresses the gas to the minimum volume (this is the second compression), the spark plug ignites.

The combustion pressure pushes the piston down. When the piston moves down to a certain position, the exhaust port is opened first, and the exhaust gas is discharged and then the air inlet is opened. New mixed gas enters the cylinder to extrude the remaining exhaust gas.

Post time: Nov-30-2022