Why Does a Motorcycle Emit Smoke?

[LeBraxton]

Motorcycle smoke emission is primarily caused by the following reasons: Excessively Rich Combustible Mixture: Black smoke usually indicates an excessively rich combustible mixture. This can occur when the mixing ratio of gasoline to oil in the fuel mixture is incorrect, or when the wrong type of oil is used. If there is too much oil or the oil quality is poor, the oil in the combustible mixture cannot burn completely, resulting in black smoke. Oil Seal Damage: In a two-stroke engine, damage to the crankshaft oil seal can cause transmission oil to leak into the crankcase and mix with the combustible mixture entering the combustion chamber, leading to excessive oil in the mixture. In a four-stroke engine, severe wear or breakage of the oil ring in the piston assembly can allow oil to enter the combustion chamber.