A motorcycle engine is a powertrain composed of numerous parts. These parts work together to ensure the basic operation of the engine and the output of power. Generally, their materials should be highly wear-resistant metals. Only in this way can the quality of the engine be guaranteed.

However, some special parts will also use some special materials. For instance, the tensioner pulley, tensioner strip, and the transmission teeth of the oil pump will adopt relatively conventional plastic materials. Such a design is not cutting corners but rather to reduce the curb weight of the engine and minimize the wear of other related parts.

The plastic gear beside the clutch of a motorcycle engine is the transmission tooth of the oil pump. Its main function is to provide power to the oil pump to ensure its normal operation.

It is well known that the lubrication of a four-stroke engine is mainly accomplished by pressure splashing, where the pressure refers to the lubrication effect produced by the oil pump.

Under normal circumstances, there are three fuel lines for the oil pump of a motorcycle engine

After the lubricating oil in the cylinder head passes through the oil filter screen and enters the oil pump, under the pressure of the oil pump, it will enter the cylinder head through the oil passage. After completing the lubrication of the relevant parts of the cylinder head, it will return to the oil pan from the small chain position.

After passing through the oil filter, the crankshaft lubricating oil enters the connecting rod rolling bearing through the oil passage on the crankshaft. Under the action of the rolling bearing, the lubricating oil will splash and lubricate the inner wall of the cylinder block.

3. The auxiliary shaft lubricating oil will also pass through the oil passage to lubricate the auxiliary shaft bearings and gears of the transmission. Its flow rate is the weakest among the three lubrication methods, but its effect is still relatively significant. If the auxiliary shaft is not lubricated, the gear shifting process of the entire transmission mechanism will be rather stiff and will not have a smooth and effortless feeling.

The above is the main function of the motorcycle oil pump and the flow direction of the engine oil. As for why the transmission teeth of the oil pump are made of plastic, it is mainly because, in terms of its transmission function, plastic gears can fully meet its working requirements. Therefore, it is not surprising that there is such a design.

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