When the engine is running, the temperature is very high. When the outside temperature is low, water will condense on the inner wall of the engine, stick to the engine and mix into the engine oil. When the motor gear is started, the relative oil flow is less, and water is easier to deposit.
Motorcycle is a kind of two-wheeled or three-wheeled vehicle driven by gasoline engine and controlled by handlebar, which is light, flexible and fast. Widely used in patrol, passenger and freight transportation, etc. It is also used as sports equipment. Generally speaking, motorcycles are divided into street cars, road racing cars, cross-country motorcycles, cruise cars, station wagons and so on.