The throttle valve without air filter whines.

This situation should be due to air leakage due to replacement of air filter, improper installation of air filter or improper installation of manifold, resulting in inhalation of a large amount of air, vibration of manifold and oil not being turned off. The engine oil with the label 10W indicates that the low-temperature flow value of the engine oil is relatively low and its frost resistance is relatively poor. Of course, this will also make the price of oil cheaper, and it doesn't mean anything. The most important thing is that the latter value represents the high temperature viscosity of the oil. The higher the viscosity value at high temperature, the protective oil film will adhere to the surface of the parts when working at high temperature, but it will also produce certain resistance to the engine operation and affect the performance of the maximum explosive force of the engine.