What Causes Abnormal Noise in a Motorcycle Engine After Shutdown?
1 Answers
Abnormal noise after a motorcycle engine shuts down is caused by the thermal expansion and contraction of the engine. Below is a detailed explanation of the abnormal noise after motorcycle shutdown: Engine Thermal Expansion and Contraction: During engine operation, different parts of the engine have varying temperatures. Due to these temperature differences, the degree of expansion in each part also varies. After the motorcycle shuts down, the engine stops working, and the various parts of the engine gradually cool down due to environmental factors. Parts with higher temperatures cool faster, while those with lower temperatures cool more slowly. Cooling leads to contraction and deformation. Faster cooling results in greater deformation, while slower cooling results in less deformation. Inconsistent deformation causes friction at connecting points, leading to abnormal noise. Additionally, the ceramic core of the three-way catalytic converter contracts at a different rate than the metal during cooling, resulting in rhythmic abnormal noise. Piston Slap: Piston slap occurs when the gap between the cylinder and piston increases due to wear, especially when the piston skirt is worn, making the knocking sound more pronounced. The noise is also more noticeable when the engine is cold or under heavy load.
