What causes motorcycle oil to turn black


In actual life, motorcycle users are often confused by […]

In actual life, motorcycle users are often confused by the fact that the engine oil has become "black". Do not know if you should change the oil at this time? And want to know why the motor oil becomes "black"?

In motorcycle four-stroke engines, incomplete combustion is caused for various reasons. In gasoline engines, this incomplete combustion product mainly forms black sludge. These sludges are easily deposited in oil pans or aggregated into larger particles, so that when the oil is lubricated, it is easy for the piston of the cylinder to form a paint film and carbon deposits, which eventually causes the piston ring to jam or pull the cylinder. Therefore, a powerful dispersant must be added to the engine oil to disperse these sludges in the oil without depositing on the piston to ensure the cleanliness of the piston and the normal operation of the engine.

Of course, if the engine is not in good working condition, the more incomplete combustion, the faster the oil becomes black.

In addition, due to environmental requirements, diesel engines have changed their design in order to reduce nitrogen oxides, thus increasing the amount of smoke.

In short, it can be understood from the following aspects:

(1) The amount of soot and sludge produced by different engine operating conditions is also different, so using the same lubricating oil, the blackening situation is different, which is mainly due to different engine operating conditions.

(2) Add different lubricating oil to the same engine, and the better the lubricating oil dispersibility, the faster it will turn black. In both cases, the quality of the oil cannot be judged by turning black.

(3) Judging whether the driving is good or bad is using the oil change index of the internal combustion engine oil. China's specifications GBT7607-95 and GBT8028-94 are all indicators of viscosity increase, acid value increase, wear (metal content increase), etc., and never use color (that is, turn black) as an indicator. Therefore, the color change is multi-faceted and cannot be used to determine the quality of the oil or whether it can be used. Therefore, it is more reasonable to judge strictly according to the oil change index. Since most driver friends and motorcycle users cannot determine the oil change period through laboratory analysis, it is recommended that you regularly replace high-quality lubricants.