What are the causes of abnormal noise in motorcycle idle speed?
1 Answers
Motorcycle idle speed abnormal noise may be caused by excessive valve clearance leading to abnormal sound; excessive clearance between the small end of the crankshaft connecting rod and the piston pin; crankshaft bearing damage; other transmission faults and loose screws causing loose connections between motorcycle components. Piston slap is caused by wear between the cylinder and piston, resulting in increased clearance, especially when the piston skirt is worn, the knocking sound will be very obvious. The noise will also increase when the engine is cold or under heavy load. Piston slap is caused by the increased clearance between the piston and cylinder, so compression will also deteriorate, engine power will decrease, wear will intensify, and noise will increase. Solutions: After the engine starts, if there is a knocking sound during low-temperature operation and the sound disappears when the temperature normalizes, it can be left untreated and continue to operate. When the engine temperature is normal and there is obvious knocking sound, high-speed operation should be avoided as much as possible, and disassembly and repair should be carried out as soon as possible. After removing the cylinder head and pulling out the piston, if severe cylinder ovality, scoring, or excessive clearance between the piston and cylinder are found, replacement should be performed, including the cylinder liner, piston, and piston rings. If the connecting rod is found to be deformed, it should be replaced as much as possible.
