How is this carburetor 1 2 3 adjusted?

In the picture, the three screws on the carburetor of motorcycle, screw 1, are used to adjust the concentration of mixed gas, so you can turn them clockwise to the end, then turn them counterclockwise for one and a half turns and then exit. This screw has been adjusted when it leaves the factory. There is no need to adjust it again under special circumstances. If there is any problem, it should be carried out by a mechanic with professional maintenance experience in combination with the actual car condition. Screw 2 is used to adjust the idle speed. Clockwise rotation can improve idle speed, and counterclockwise rotation can reduce idle speed. Idle speed is subject to the state when the car is hot. Screw 3 is the oil drain screw of the carburetor. Loosen or remove it to release the gasoline in the carburetor and fuel tank.