What are the consequences of excessive or insufficient valve clearance in motorcycles?

[Raphael]

The consequences of excessive valve clearance in motorcycles are: 1. Valve noise: The sound mainly comes from the collision between the rocker arm and the valve; 2. Reduced power: The valve opening will become smaller, thereby affecting the engine's intake and exhaust volume; 3. Unexpected damage: There is a possibility of push rod detachment. The consequences of insufficient valve clearance in motorcycles are: 1. Difficulty in cold starts; 2. No idle or unstable idle, reduced power; 3. Increased wear on the valve rocker arm and camshaft. The intake and exhaust valve clearance for ordinary motorcycles is generally around 0.05 to 0.12 millimeters, and the valve clearance may vary for different models. When there is obvious up and down clearance in the valve rocker arm, it indicates excessive clearance; if the rocker arm feels very tight with no clearance when moved by hand, it indicates insufficient clearance.