There are many reasons for the abnormal noise of the motorcycle, including the abnormal noise of the engine and the whole vehicle. Even if the engine makes abnormal noise, there may be many reasons. The engine is composed of many parts, many of which run at high speed. Almost any human part that has a problem may cause abnormal noise, but the sound problem cannot be heard and cannot be judged, Therefore, they had to go to the local after-sales service or repair place for maintenance.
 The abnormal noise of motorcycle engine is mostly related to the valve distribution system, such as timing chain and tensioner, valve ejector rod, camshaft and valve rocker arm, valve clearance, cylinder piston, etc. The abnormal noise of four stroke motorcycle engine is mostly related to these aspects.
 However, there are also some benign and normal sounds in the engine. Although these sounds cannot be eliminated, they will not continue to expand or cause faults. This kind of sound can be ignored. After all, with so many parts running at high speed, it is impossible to have no sound at all.