作为摩托车初级传动的曲轴齿轮及初级从动齿轮，由于转速高及降速比大，是产生噪声的主要因素。

The primary drive gear(crankshaft gear)and the primary driven gear are the source of noise due to their high speed and bigger reduction ratio.

youdao

作为摩托车初级传动的曲轴齿轮及初级从动齿轮，由于转速高及降速比大，是产生噪声的主要因素。

The primary drive gear(crankshaft gear)and the primary driven gear are the source of noise due to their high speed and bigger reduction ratio.

youdao