When we remove the motorcycle spark plug for inspection, we can judge by observing the surface of the spark plug. By observing the working conditions of the spark plug electrodes, it is possible to roughly judge whether the engine is working normally. 1. If the surface of the motorcycle spark plug is clean and the electrode color is brown, yellow, or yellow-white, it means it is in good condition. 2. If the surface of the electrode is wet, it means that the gasoline is not fully burned, and it is difficult to start after the flame is turned off. This often happens after long periods of idling and pounding the throttle.​​

3. If there are oil stains on the electrode surface of the motorcycle spark plug, it means that other oils such as engine oil have penetrated into the combustion chamber, such as serious wear of the cylinder, piston, and piston ring, blockage of the crankcase ventilation device, causing the oil to run up, etc.
4. If the surface of the motorcycle spark plug is black with ablation spots, carbon deposits, or white, it means that the spark plug is overheated and the carbon deposits need to be replaced. It is caused by the mixture being too rich or running under low load conditions for a long time. Carbon deposits on the spark plug are equivalent to connecting a shunt resistor in parallel between the two electrodes, resulting in premature leakage or weak high-voltage sparks.​​
5. If there are water droplets on the electrode surface of the motorcycle spark plug, it means that there is water intrusion in the cylinder, often because the cylinder gasket is not tightly sealed or damaged; the cylinder or cylinder head is cracked, causing cooling water to enter the cylinder or gasoline mixed with moisture.
In short, the motorcycle spark plug is a very critical component, and the performance of the spark plug also directly affects the performance of the vehicle. If the ignition performance of the spark plug is not good, it will not only be difficult to start, the vehicle will be weak, and the oil and gas combustion will not be complete. This will also lead to increased fuel consumption in the long run, and even seriously affect the service life of the engine.
Through the above introduction and analysis of the features of the motorcycle spark plug, hope it helps you.