How to Determine if a Motorcycle's Air-Fuel Mixture is Too Rich?

[DeNoah]

Simply check the color of the spark plug; if it appears carbon black, it indicates an overly rich air-fuel mixture. Below is relevant information about motorcycle air-fuel mixtures: 1. Overly rich motorcycle air-fuel mixture: Unburned excess gasoline may cause the exhaust pipe to backfire once or twice during mid-to-high speed deceleration. The motorcycle may feel slightly more powerful but becomes difficult to restart after stalling when hot. Excessive black smoke, elevated engine temperature, and overheating damage to valve components from detonation may occur. Engine oil may appear darker. Spark plugs may show signs of carbon fouling, and carbon deposits inside the cylinder may increase. 2. Overly lean air-fuel mixture: Symptoms include difficulty starting, unstable idle speed prone to stalling, carburetor backfiring, insufficient power with unresponsive throttle. Whether the mixture is too rich or too lean, both conditions affect normal engine operation, produce abnormal reactions, and neither improves fuel efficiency.