Yamaha 2007 FZ6-NA Service Manual

Contents

FEATURES1-11Wheel slip and hydraulic controlThe ABS ECU calculates the wheel speed of each wheel according to the rotation signal receivedfrom the front and rear wheel sensors. In addition, the ABS ECU calculates the vehicle chassisspeed and the rate of speed reduction based on the wheel speed values.The difference between the chassis speed and the wheel speed calculated in the slip ratio formula isequal to the wheel slip. When the wheel speed is suddenly reduced, the wheel has a tendency tolock. When the wheel slip and the wheel speed reduction rate exceed the preset values, the ABSECU determines that the wheel has a tendency to lock.If the slip is large and the wheel has a tendency to lock (point A in the following figure), the ABSECU reduces the brake fluid pressure in the brake caliper. The ABS ECU increases the pressure ofthe brake fluid in the brake caliper when the tendency to lock has diminished (point B in the followingfigure).ABS operation and vehicle controlIf the ABS starts operating, there is a tendency of the wheel to lock, and the vehicle is approachingthe limit of control. To make the rider aware of this condition, the ABS has been designed to gener-ate a reaction-force pulsating action in the brake lever and brake pedal independently.NOTE:When the ABS is activated, a pulsating action may be felt at the brake lever or brake pedal, but thisdoes not indicate a malfunction.The higher the side force on a tire, the less traction there is available for braking. This is truewhether the vehicle is equipped with ABS or not. Therefore, sudden braking while cornering is notrecommended. Excessive side force, which ABS cannot prevent, could cause the tire to slip side-ways.f. Controlling zoneg. Slippery road surfacea. Vehicle speedb. Wheel speedc. Pressurizedd. Depressurizede. Brake force