Chapter 3 Complete Motorcycle; Section 1 Fuel Supply System - ZONGSHEN ZS125-86 Service Manual

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Table Of Contents

Table of Contents

The oil supply system includes a fuel tank, fuel pump, fuel injector, fuel filter and oil tube.

1. Structure and Working Principles of Fuel System

[1.]Fuel tank

The fuel tank is usually made of a 0.8mm ~ 1.0mm thick steel plate processed through stamping

and jointing. Some tanks have division plate with holes inside, which not only improves the tank

strength, but also prevents fuel from surging when the vehicle is driving. As the gasoline is strongly

corrosive, the internal tank surface should be galvanized or otherwise as an anti-corrosion treatment.

The top of the tank is equipped with a fuel filler and is covered with a fuel tank cap with a vent hole.

This prevents the fuel from overflowing when the motorcycle is driving and also maintains the balance

between the internal and external air pressure, so that the fuel can flow out naturally.

[2.]Fuel pump

The fuel pump assembly is composed of an oil pump, a bracket and an oil pressure regulator. The

elastic installation method can reduce the direct impact of vibration on the fuel pump. The fuel pump

installed in the fuel tank can make the oil supply system simple and hinder the fuel leakage.

The fuel pump is a turbine single-stage electric fuel pump, driven by a 12-volt DC motor and

controlled by ECU through the fuel pump relay. The pump outlet is designed with a one-way valve, so

that the stored oil in the tube will not retreat to the fuel tank when the engine does not work, to ensure

re-start performance.

[3.]Fuel injector

The fuel injector timely and exactly injects moderate atomized fuel into the engine intake pipe, and

then the atomized fuel is further sucked into the cylinder for combustion.

[4.]Fuel filter