2008 Yamaha Rhino YXR70FX Factory Service Manual, Page 20Get this manual
FEATURES EAS20170
GEN INFO
FEATURES
OUTLINE OF THE FI SYSTEM The main function of fuel supply system is to provide fuel to the combustion chamber at the optimum air-fuel ratio in accordance with the engine operating conditions and the atmospheric temperatureIn the conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the combustion chamber is created by the volume of the intake air and the fuel that is metered by the jet used in the respective carburetorDespite the same volume of intake air, the fuel volume requirement varies with the engine operating conditions, such as acceleration, deceleration, or operating under heavy loadCarburetors that meter the fuel through the use of jets have been provided with various auxiliary devices, so that an optimum air-fuel ratio can be achieved to accommodate the constant changes in the operating conditions of the engineAs the requirements for the engine to deliver more performance and cleaner exhaust gases increase, it becomes necessary to control the air-fuel ratio in more precise and finely tuned mannerTo accommodate this need, this model has adopted an electronically controlled fuel injection (FI) system, in place of the conventional carburetor systemThis system can achieve an optimum air-fuel ratio required by the engine at all times by using microprocessor that regulates the fuel injection volume according to the engine operating conditions detected by various sensorsThe adoption of the FI system has resulted in highly precise fuel supply, improved engine response, better fuel economy, and reduced exhaust emissions