Sound Identification: Timing gears, chains, and belts can produce noise varying from a high-pitched howl (fitted too tight) to a low-level chatter or growl (badly worn).

• 声音辨别：正时齿轮，正时链条和正时皮带可以制造各种不同的噪音，从尖锐的啸声（安装的太紧）到低沉的卡嗒声或轰鸣声（磨损太大）。