Why do motorcycle exhaust pipes emit black and white smoke

Fault analysis:

(1) when the engine works, if the exhaust pipe will have blue smoke discharge, the possible phenomenon is that the oil consumption is too fast, the failure may be due to the excessive oil quantity, the compression pressure of the cylinder is lower than the specified value, the gap between the piston and the cylinder wall is too large, the piston ring wear and seal is poor, first check the oil quantity, because too much oil is easy to cause the oil to run up.

When the oil level is checked, and the engine can not be checked after the engine has just turned off, the inspection shall be carried out after 10 minutes of fire-out. If the oil level is high, the excess oil shall be drawn or discharged, and if the oil level of the oil is normal, the cylinder pressure and the wear of the piston, the piston ring and the wall of the cylinder shall be checked and the possibility of increasing the clearance shall be checked if the oil level of the oil is normal and the oil level of the piston and the piston ring and the cylinder wall is increased, so that the oil can flow upwards.

If the pressure of the cylinder is lower than the specified value, check whether the piston ring has the product of stuck, worn or even elastic loss. If the above-mentioned situation occurs, the piston ring shall be cleaned or replaced.

In case of serious wear of the cylinder wall, when the clearance between the piston and the cylinder exceeds the fixed value, make the cylinder, replace the piston and other methods. For engines that have just undergone a major overhaul or a change over the piston ring, it is often caused by the inner and outer cut (chamfers) of the piston ring. If this occurs, re-install the piston ring.

(II) the breakdown of black smoke is:

When the engine is in operation, the exhaust pipe takes black smoke and can smell the slight gasoline smell, and the oil filling door is more obvious. The cause of the failure may be that the mixed gas is too rich, the spark plug is not working properly.

This should check the concentration of the mixed gas and, after this symptom, first check the throttle.

In the normal operation of the engine, the operation mechanism is stuck, and the failure is not normally open and closed, and if it is to be repaired or replaced. Second, check whether the filter of gasoline and air is blocked seriously, etc. Check the spark plug for fire.

If the spark plug is weak or the fire is not normal, the mixed gas will not be fully combusted, and the black smoke will appear.

Pull off the spark plug. If the spark is normal and the spark is strong, it will be indicated that there is no fault in the spark plug. If the spark of the spark plug is not running along the electrode, but the surrounding is jumping, it is indicated that the spark plug is not working normally, and a new spark plug should be replaced. If the carbon of the spark plug is serious, it is recommended to replace it.

Engine exhaust pipe in the process of black smoke, if there is a "sudden" sound and "fire" sound, it means that the ignition is too late. If the above situation occurs, correct it in time.

(III) the breakdown of white smoke is:

Fuel and cylinder or muffler contain moisture, if there is always white smoke phenomenon, indicating that the fuel is not up to standard, the fuel should be replaced with good quality fuel. If only white smoke is emitted at startup and disappears after normal operation, this problem is a normal phenomenon.

However, there is a kind of engine that must have smoke, which is called a two-stroke engine, because the design is different from a four-stroke engine, there is no valve in the reciprocating motion of the piston, and additional oil is needed to lubricate the engine, so the engine must have blue smoke in normal operation.