Remove the radiator cap in two steps. First turn the cap counterclockwise to the first stop. Then push and turn it further in the same direction and remove the cap.

NOTE
Wet the cap sealing surfaces with water or coolant to prevent pressure leaks.

NOTICE
During pressure testing, do not exceed the pressure for which the system is designed. The maximum pressure is 142 kPa (1.45 kgf/cm², 21 psi).
If the pressure holds steady, the system is all right.
If the pressure drops and no external source is found, check for internal leaks. Droplets in the engine oil indicate internal leakage. Check the cylinder head gasket and the water pump.
Remove the pressure tester, replenish the coolant, and install the radiator cap.
Coolant Deterioration Inspection
Cooling System FlushingBrake Line Bleeding
The brake fluid has a very low compression coefficient so
that almost all the movement of the brake lever or pedal
is transmitted directly to the caliper for braking action. Air,
however, is easily compressed. When air enters the brake
lines, brake lever or pedal movement will be partially used
...
Radiator Hose and O-ring Replacement
Drain the coolant (see Coolant Change).
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Thermostat Housing [A] (see Thermostat Removal in the
Cooling System chapter)
Oil Cooler [B] (see Oil Cooler Removal in the Engine
Lubrication System chap ...
Air Switching Valve (Service Code 64)
Air Switching Valve Removal/Installation
Refer to the Air Switching Valve Removal/Installation in
the Engine Top End chapter.
Air Switching Valve Inspection
Refer to the Air Switching Valve Unit Test in the Electrical
System chapter.
If the air switching valve [A] is normal, check ...