Carburetor structure of large row motorcycle

The working principle of vacuum carburetor is simple:

When the throttle pipe is pulled to open the throttle, a vacuum is formed in the throat, and the vacuum film is sucked away, so that the needle valve of the main metering hole (what you call "vacuum needle") is upward, and the main metering hole supplies oil to the engine. The needle valve of the main metering hole is conical, and the higher the upward lift, the greater the oil supply.

When you say auxiliary metering hole, it is actually called cannon metering hole. When the main metering hole is short of oil, the metering hole is used to assist in supplying oil to the engine. When you accelerate sharply, the cannon metering hole will work.

There is also an idle metering hole, which is responsible for providing fuel to the engine when the engine is idling. Some carburetors also have cold cars and electronic concentration valves. Navajo will start when the car is cold, and it will shut down after 1~2 minutes.

The vacuum carburetor has a float chamber with a float in it. The function of the float is to control the oil level in the float chamber. If it goes up, the oil level will be high, if it goes down, the opposite will happen.

There is no picture. If you really want to know about it, you can look at what I said while unpacking. All carburetors work on the same principle.