What causes motorcycle spark plugs to turn black?

The reasons why motorcycle spark plugs turn black are:
1. The mixture is rich, the gap in the valve mechanism is large, and the calorific value of the spark plug is wrong;
2. Burning engine oil, the oil enters the combustion chamber of the engine and participates in combustion together with the mixture, which will cause the vehicle's oxygen sensor to be damaged too quickly, leading to increased carbon deposits in the combustion chamber, unstable idling, weak acceleration, increased fuel consumption, and exhaust emissions. Exceeding the standard and other adverse consequences. The flower plug is commonly known as the burner. Its function is to discharge the pulsed high-voltage electricity sent from the high-voltage wire (burner wire), breakdown the air between the two electrodes of the spark plug, and generate an electric spark to ignite the mixed gas in the cylinder.