After cleaning the throttle, the engine sound is louder than before. What happened?

1, the oil does not meet the standard or is added too much.

When the engine oil in the cylinder is too full, it will produce greater unnecessary resistance to the rotation of the crankshaft, which will further affect the power output and increase fuel consumption. The amount of engine oil entering the combustion chamber is greatly increased, which increases the carbon deposition in the combustion chamber, increases the piston movement resistance and reduces the engine power. Excessive engine oil will flow into the combustion chamber from the gap between the cylinder and the piston, and burn to form carbon deposit. These carbon deposits will increase the compression ratio of the engine and increase the tendency of knocking; The carbon deposit in the cylinder is red and hot, which is easy to cause premature combustion. If it falls into the cylinder, it will aggravate the wear of the cylinder and piston and accelerate the pollution of oil. Secondly, too much oil increases the mixing resistance of crankshaft connecting rod, and the noise will also increase.

2. The viscosity of oil should be selected correctly.

Different grades of engine oil have different characteristics, and their low-temperature startability, high-temperature wear resistance and adhesion also have different performances. The viscosity of engine oil is inversely proportional to temperature. When the engine is cold, the viscosity of engine oil is very high. If the selected oil is thick, it will add extra loss to the starting motor and battery. However, if the oil is too thin, it is difficult to form enough protective film at high temperature, resulting in insufficient lubrication and increased parts wear.

For example, many riders didn't notice the original requirement of using 5W30 in the vehicle manual, so they directly used 5W30 engine oil. As a result, they felt that it was not suitable for their own car after using it. Later, after switching to 5W30, the noise was loud at first, and it dropped after driving for a while. This is normal. If the vehicle specification requires 5W40, in order to speed up and save fuel, riders only need to add 5W30/20 engine oil to it. It was noisy at first, but after driving for a while, the noise decreased. This is normal. If the sound doesn't stop, it's not normal. It is suggested to change the label required in the manual.

3. Carbon deposition

Moderate carbon deposition, because the old engine oil is used more and more thinly, so too much carbon deposition will affect the power. However, after the engine oil is diluted, it makes up for the power loss after more carbon deposition. As a result, the viscosity of new engine oil is high, but it shows problems. Using high-grade gasoline to increase the speed, it is best to keep driving above 2500 rpm, and opening a box of high-grade gasoline should improve it.