1. In the case of constant engine speed, it is obvious that the driving speed is lower than before.
2. Although the engine speed increased, but the speed change is not obvious;
3. Prop up the main bracket, let the rear wheel leave the ground, hang 1 stalls, keep the small throttle, slow down the brake pedal, obviously feel the rear wheel start to brake, but the engine speed is not reduced obviously;
4. Through the oil color judgment: When replacing oil, the black oil inside has a little gray material, may judge is the clutch wear, if the clutch burns seriously, the oil is black grey mixture;
5. Through the oil taste judgement: The engine overheating after emitting abnormal coke odor, or change the oil timing oil has obvious coke odor.