What sound does a motorcycle crankshaft make when it's broken?
2 Answers
When the crankshaft rotates, the flywheel will swing back and forth, causing the crankshaft to hit in areas with large gaps, producing a dull, muffled knocking sound. Below is more information about the crankshaft: 1. Rotating component: The main rotating component of the engine. After connecting with the connecting rod, it converts the up-and-down (reciprocating) motion of the connecting rod into a circular (rotational) motion. It is an important component of the engine, made of carbon structural steel or nodular cast iron. 2. Main shaft: The main journal is installed on the cylinder block, the connecting rod journal connects with the big end hole of the connecting rod, and the small end hole of the connecting rod connects with the cylinder piston, forming a typical slider-crank mechanism. 3. Crankshaft lubrication: Crankshaft lubrication mainly refers to the lubrication between the connecting rod big end bearing and the crankshaft connecting rod journal, as well as the lubrication at the two fixed points. The rotation of the crankshaft is the power source of the engine and the driving force of the entire mechanical system.
As a frequent motorcycle rider, when the crankshaft fails, the sound is particularly harsh, like metal clashing—clicking and clanking noises, sometimes accompanied by sharp, irregular sounds. When the engine speed becomes unstable, you can feel the entire bike shaking violently, as if there's a little hammer banging around inside. It's not the smooth hum of a normal engine running but more like a signal of parts falling apart. The crankshaft endures tremendous stress, and failure is usually caused by insufficient oil or long-term wear, leading to bearing looseness or crankshaft arm breakage. Upon hearing such sounds, you must stop immediately and inspect the bike. Continuing to ride could result in complete engine failure, which is extremely dangerous. Preventive measures include regular oil changes and maintenance, as well as checking oil pressure. Riding safety comes first—don't ignore these strange noises. It's best to take it to a professional shop for disassembly and repair.
