Mechanism characteristics
Yamaha developed the YCC-T and YCC-I system employing the most advanced electronic control technologies. Electronic control throttle systems have been used on automobiles, but Yamaha has developed a faster, more compact system specifically for the needs of a sports motorcycle. The Yamaha-developed system has a high-speed calculating capacity that produces computations of running conditions every 1/1000th of a second.
The YCC-T system is designed to respond to the throttle action of the rider by having the ECU instantaneously calculate the ideal throttle valve opening and generate signals to operate the motor-driven throttle valves and thus actively control the intake air volume.
The ECU contains three CPUs with a capacity about five times that of conventional units, making it possible for the system to respond extremely quickly to the slightest adjustments made by the rider. In particular, optimized control of the throttle valve opening provides the optimum volume of intake air for easy-to-use torque, even in a high-revving engine.
The YCC-I system calculates the value from the engine revolution number and throttle opening rate, activates the intake air funnel with the electronic control motor drive to control the intake pipe length in order to gain the high power output in all revolution ranges from low speeds to high speeds.
Aims and advantages of using YCC-T system
- Increased engine power
- By shortening the air intake path, higher engine speed is possible - Increased engine power.
- Improved driveability
- Air intake volume is controlled according to the operating conditions - Improved throttle response to meet engine requirement.
- Driving force is controlled at the optimal level according to the transmission gear position and engine speed - Improved throttle control.
- Engine braking control
- Due to the throttle control, optimal engine braking is made possible.
- Simplified idle speed control (ISC) mechanism
- The bypass mechanism and ISC actuator are eliminated - A simple mechanism is used to maintain a steady idle speed.
- Reduced weight
Compared to using a sub-throttle mechanism, weight is reduced.
![](https://motoinstruction.ru/img/yamaha/20/126175.jpg)
A. To throttle grip; 1. Throttle servo motor; 2. Accelerator position sensor; 3. Throttle cable pulley with linkage guard; 4. Throttle valves; 5. Throttle position sensor
Aims and advantages of using YCC-I system
- Improvement of the engine power characteristics
The high power design in all ranges is now provided by having both two features of the short intake function to ensure the power at the high speed revolution of engine, and the long intake function to ensure the power in the practical use range.
- Intake pipe length switching control using the motor
The intake pipe length switching operation in a minute time is now available by means of the motor drive using the electronic control. The smooth power characteristic is provided, which does not let an operator feel the switching action by the optimization of its switching revolution number and the most suitable application of engine at the time of changing the revolution.
![](https://motoinstruction.ru/img/yamaha/20/126176.jpg)
A. Down position (long intake) (Low rpm to Mid rpm); B. Up position (short intake) (High rpm)