When maintaining the air filter, carefully check the color and contrast of the filter paper on the inner and outer surfaces of the paper filter element. The color of the used filter element is gray-black due to the deposit of dust on the outer surface of the side in contact with the atmosphere; The inner surface of the filter paper facing the air inlet should still show its natural color. If the dust on the outer surface of the filter element is removed and the original color of the filter paper can be revealed, the filter element can continue to be used. 

1. Loosen the filter lock, remove the nut that fixes the filter element, remove the protective cover and pull out the filter element. Take out the filter element and take care to prevent impurities from falling into the carburetor. Wipe the inside and outside of the air filter housing with a rag and gasoline;

2. Starting from the inside of the filter element, blow off the dust on the inner and outer surfaces of the filter element evenly along an oblique angle. If there is no compressed air, tap the filter element with a screwdriver handle, and then use a brush to clean the external dirt;
3. Check the filter element after cleaning and drying. Turn on the illuminator and put it inside the filter element to observe from the outside for damage, small holes or thinned parts, and check the rubber gasket for damage. If there is any abnormality, replace the filter element and gasket;
4. Replace the element of the air cleaner. Replace according to the regulations of each model. When replacing the filter element, pay attention to check whether the new filter element is damaged, whether the gasket is defective, and if any defect is found, it should be equipped;
5. Install the air filter. After the filter element is cleaned, install the components in the reverse order of disassembly. The filter element must be installed reliably, and it is not advisable to touch the paper part of the filter element with hands or utensils, especially not to allow oil to contaminate the filter element.