Yamaha YZF-R125 Service Manual: Checking the radiator
1. Check:
Radiator fins
obstruction 
clean.
Apply compressed air to the rear of the radiator.
Damage
repair or replace.
NOTE:
Straighten any flattened fins with a thin, flat-head screwdriver.
2. Check:
- Radiator hoses
Cracks/damage
Replace.
3. Measure:
- Radiator cap opening pressure
Below the specified pressure
Replace the radiator cap.
a. Install the radiator cap tester "1" and radiator
cap tester adapter "2" to the radiator cap "3".
b. Apply the specified pressure for ten seconds and make sure there is no drop in pressure.
4. Check:
- Radiator fan
Damage
Replace.
Malfunction
Check and repair.Refer to "COOLING SYSTEM" on page 8-25.
Radiator
...
Installing the radiator
1. Fill:
Cooling system
(with the specified amount of the recommended
coolant)
Refer to "CHANGING THE COOLANT" on
page 3-15.
2. Check:
Cooling system
Leaks Repair or replace any
...
Other materials:
Removing the valves
The following procedure applies to all of the
valves and related components.
NOTE:
Before removing the internal parts of the cylinder
head (e.g., valves, valve springs, valve seats),
make sure the valves properly seal.
1. Check:
Valve sealing
Leakage at the valve seat Check
the valve
...
Checking the condition of the bulb sockets
The following procedure applies to all of the bulb
sockets.
1. Check:
Bulb socket (for continuity)
(with the pocket tester)
No continuity Replace.
NOTE:
Check each bulb socket for continuity in the
same manner as described in the bulb section,
however, note the following.
a. Install a ...
Checking the steering
Worn or loose steering bearings may
cause danger. Therefore, the operation
of the steering must be checked as follows
at the intervals specified in the periodic
maintenance and lubrication
chart.
Place a stand under the engine to
raise the front wheel off the
ground. WARNING! To ...