The oil filter is mainly used to remove impurities such as dust, metal particles, carbon sediments and soot particles in the oil, so as to protect the engine.
When a four-stroke motorcycle is driving, if there is more smoke, it indicates that the engine has a failure, and it should be repaired in time after finding out the cause.
A domestic single-cylinder 125 motorcycle traveled more than 40,000 kilometers, and forgot to change the oil once, resulting in serious wear of the cylinder piston as shown in Figure 1.