Chassis; Anti-Look Brake System; Terms Explanation - Yamaha YP250A 1999 Supplementary Service Manual

ANTI-LOCK BRAKE SYSTEM (ABS)
ANTI-LOCK BRAKE SYSTEM
The YAMAHA ABS is the electronic control sys-
tem applying the 2 system control type with the in-
dependent hydraulic system for the front and rear
wheels respectively.
Accordingly, the brake operation is the same as
usual scooters providing the right hand brake le-
ver to be used for the front wheel and left hand
brake lever for the rear wheel.
When the locking movement of wheels due to ur-
gent braking is detected on each wheel, the inde-
pendent hydraulic control is performed by each
brake hydraulic system.

TERMS EXPLANATION

S Wheel speed
Rotation speed of front and rear wheels itself is
the wheel speed.
S Chassis speed
When the brake is applied, the wheel rotation is
lowered and the chassis speed reduces. Howev-
er, the chassis tends to travel forward by its iner-
tia even though the wheel rotation is lowered.
The speed of chassis itself is the chassis speed.
S Brake force
This is the force to reduce the speed by braking.
S Wheel lock
On a slippery road, if the brake was applied too
strong the vehicle tends to run on, but the wheels
stop rotating. This state is called a wheel lock.
S Side force
This is the force to act on tires which supports the
vehicle sideways.
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CHAS

CHASSIS