What symptom is motorcycle carburetor broken?

1, carburetor backfire sound

Tempering sounds appear in two situations. One is that the air filter makes a "click" when starting, and white smoke comes out, making it difficult for the engine to start; The other is that the engine suddenly pops out of the air filter while working.

2. Knocking sound of carburetor throttle

The throttle keeps moving up and down in the mixing chamber, and excessive wear leads to excessive clearance. In the intake stroke of the engine, due to the impact of airflow, the throttle swings radially and hits the mixing chamber, which will make a "giggle" sound. This noise is almost inaudible when idling, and the noise is the largest when the throttle is turned to 1/4. When the throttle is turned on again, the noise gradually decreases, and when the throttle is turned to the bottom, the noise disappears.

When checking, you can press the carburetor with a screwdriver to listen. When the accelerator is increased to 1/4, there is obvious knocking sound. You can also take off the air filter, put your finger against the throttle, the knocking disappears, and the relaxed finger knocking starts again, so you can conclude that it is the knocking of the throttle.

3. Foreign matter adheres to the contact surface between the needle valve and the valve seat.

Reason: The needle valve and valve seat control the oil intake, and their sealing requirements are strict and the contact surface is smooth. If foreign matter is attached to the contact surface, the needle valve and valve seat are not tightly sealed, resulting in oil leakage. Foreign matter mainly refers to impurities and condensed colloid in gasoline. Therefore, in order to avoid such failures, users should pay attention to cleaning the gasoline filter regularly and use good quality gasoline.

4, carburetor acceleration transition is not smooth.

The fuel supply of carburetor idle oil system decreases gradually, while the fuel supply of main oil system increases. The phenomenon of poor transition is that the engine speed fluctuates greatly when starting to accelerate or flameout with the expansion of throttle.

5. Is the carburetor idling?

After the engine is warmed up for a few minutes, the engine idle speed fluctuates more than 100 rpm, indicating that the idle speed is unstable.

Extended data:

Normal maintenance method of carburetor

If the gasoline enters the carburetor from the fuel tank and then passes through the gasoline filter, the gasoline filter can filter out impurities mixed in the gasoline and scale in the fuel tank. If the filter is defective, some impurities will still enter the carburetor through the filter. In addition, gasoline contains components that can form colloid, which will condense after a long period of deposition and attach to carburetor parts (such as metering holes), oil circuits and the surface of float chamber.

Air enters the carburetor through the air filter. Considering the intake resistance and other factors, the filter device should not be too dense, so that some tiny impurities in the air will still enter the carburetor through the air filter. If the quality of the filter element is defective, it will have a more serious impact.

Many parts in carburetor oil circuit and gas circuit, such as main metering hole, idle metering hole, main air metering hole, idle metering hole, main foam pipe, etc. , all have holes with very small inner diameter (the inner diameter is between 0.3 and 1.5 mm). Gasoline impurities, colloid and impurities in the air entering the carburetor often change or block these small holes, resulting in poor gas and oil circuits of the carburetor.

The normal maintenance of carburetor is actually to keep the cleanliness of carburetor when it leaves the factory. In our company and other professional carburetor manufacturers, it is controlled as a key index of carburetor quality evaluation. In order to meet the control standards of Keihin Company in Japan, all kinds of advanced equipment and technology are adopted to strictly control every link of production.

Therefore, in order to ensure the normal use of the motorcycle, we must pay attention to the normal maintenance of the carburetor: clean the carburetor regularly, keep the oil circuit and air passage of the carburetor clean, and keep the small aperture unobstructed. This is also very important to prolong the service life of carburetor. From experience, many carburetor performance failures can be solved by cleaning the carburetor regularly.