As the tire tread wears down, the tire becomes more susceptible to puncture and failure. An accepted estimate is that 90% of all tire failures occur during the last 10% of tread life (90% worn). So it is false economy and unsafe to use the tires until they are bald.
If any measurement is less than the service limit, replace the tire (see Tire Removal/Installation in the Wheels/Tires chapter).

Tread Depth Standard:
Front 3.6 mm (0.14 in.)
Rear 5.3 mm (0.21 in.)
Service Limit:
Front 1 mm (0.04 in.) (AT, CH, DE) 1.6 mm (0.06 in.)
Rear 2 mm (0.08 in.) (Up to 130 km/h (80 mph)) 3 mm (0.12 in.) (Over 130 km/h (80 mph))
| WARNING Some replacement tires may adversely affect handling and cause an accident resulting in serious injury or death. To ensure proper handling and stability, use only the recommended standard tires for replacement, inflated to the standard pressure. |
NOTE
Wheel/Tire Damage Inspection
Wheel Bearing Damage InspectionThrottle Body Assy Installation
Apply a thin coat of grease to the throttle cable lower ends.
Fit the accelerator cable end [A] and the decelerator cable
end [B] into the throttle pulley.
Install the clamp [C] securely.
Install the throttle body assy holder clamp bolt heads [A]
outside as shown in the figure.
...
Oxygen Sensor Removal (Equipped Models)
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Disconnect the oxygen sensor lead connector [A].
NOTICE
Do not pull strongly, twist, or bend the oxygen sensor
lead. This may cause the wi ...
Subthrottle Valve Actuator Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector and
connect the measuring adapter [A] between these connectors
as shown in the figure.
Main Harness [B]
Subthrottle Valve Actuator [C]
Special Tool ...