What Causes Abnormal Noises in Motorcycle Engines?
2 Answers
Motorcycle engine abnormal noises may be caused by the following reasons: Excessive clearance between piston and cylinder wall: Over-tight piston pin assembly or connecting rod bearing assembly; Excessive clearance between tappet and its guide hole; Wear of camshaft profile; Sometimes, loose starter clutch causing pulley noise (especially noticeable during speed changes). Excessive valve clearance: Excessive clearance between tappet and its guide hole; Camshaft profile wear; Excessive clearance between valve stem and its guide; Broken valve spring; Radial fracture of camshaft timing gear; Loose valve seat; Stuck valve that cannot close. Excessive clearance between piston and cylinder wall: Piston issues due to incorrect depth and width of main bearing oil groove; Poor lubrication caused by low oil pressure.
I've been riding motorcycles for over a decade and have encountered engine abnormal noise issues several times. Let me share some experience. Common causes include improperly adjusted valve clearance, which produces ticking noises; insufficient or poor-quality engine oil causing increased friction and squeaking sounds; loose chains or belts creating rustling noises; piston slap or bearing wear resulting in alarming clunking sounds; and incorrect spark plug timing leading to popping sounds. When you notice unusual noises, stop riding immediately to avoid further damage. You can perform simple checks like oil level and chain tension yourself, but if the problem persists, take it to a professional shop. Regular motorcycle maintenance is crucial - I change oil and inspect components periodically to prevent many issues. Riding safety comes first - abnormal noises can indicate serious problems, so never take risks.
