How is there a black stain on the motorcycle exhaust pipe?

The blackening of motorcycle exhaust pipe can be judged as the incomplete combustion of combustible gas leading to black smoke.

1. When the motorcycle is in use, because the inhaled air contains fine dust, it can't be completely filtered out at the air filter, and the back of the valve will be washed by oil and gas, which will leave tiny scratches on the back of the valve for a long time. Fine particles and lubricating oil in the crankcase will stick to scratches, form paint at high temperature, accumulate for a long time, and mix with wax and other components in fuel to form carbon deposit.

2. Gasoline is easy to react with air during transportation to generate colloidal substances, or the colloid content of gasoline itself is high (poor quality of gasoline). These colloids enter the combustion chamber with gasoline through the fuel supply system of vehicles, and then burn with gasoline, which will cause a lot of carbon deposition in the fuel supply system, such as fuel injectors, engine combustion chambers, piston ring grooves, spark plugs, the back of intake valves, intake air, etc.

Methods of removing carbon deposits:

1, the traditional disassembly method cleans up the carbon deposit. The engine intake system (throttle valve, intake port, valve, nozzle and air sensor), combustion system (combustion chamber, piston, piston ring, spark plug and nozzle) and exhaust system (exhaust valve, oxygen sensor, exhaust port and three-way catalytic cracking) are disassembled, and only a part of them can be cleaned, while others cannot be cleaned manually.

Because some spare parts need to be replaced after disintegration, such as cylinder gasket, inlet and outlet interface gasket, bolt and nut, three-way catalytic cracking, sensor and so on.

2. Chemical reagents are classified to remove carbon deposits. There are many methods for throttle, air inlet, combustion chamber, oil nozzle and three-way catalytic cracking. For example, the spray for cleaning the throttle, the bottle for cleaning the combustion chamber and the cleaning liquid for cleaning the fuel nozzle must be added to the fuel supply system.

Most chemicals not only corrode engine metal materials, but also block and corrode three-way catalytic cracking. The most terrible chemicals contain lipids, ethers, strong acids and alkalis, sodium salts and other chemical components.