An improving design on the variable intake port of a 1.25l 4 valve single cylinder engine is conducted for optimizing the small and medium load performance of the engine.

对一1.25 L单缸4气门发动机进行可变进气的改进设计，以便优化发动机的中小负荷性能。

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Variable valve train enables the engine to achieve the best valve timing at a very high speed and load. Thus the performance of the engine can be improved.

配气可变机构可使发动机在较高转速和全负荷范围都能得到最佳配气，因而改善了发动机性能。

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