Yamaha YZF-R125 Service Manual: Checking the thermostat
1. Check:
- Thermostat
Does not open at 80.5-83.5 C (176.9-182.3
F)
Replace.
a. Suspend the thermostat "1" in a container "2" filled with water.
b. Slowly heat the water "3".
c. Place a thermometer "4" in the water.
d. While stirring the water, observe the thermostat and thermometer's indicated temperature.
A. Fully closed
B. Fully open
NOTE:
If the accuracy of the thermostat is in doubt, replace it. A faulty thermostat could cause serious overheating or overcooling.
2. Check:
- Thermostat cover
Cracks/damage
Replace.
3. Check:
- Radiator inlet hose
Cracks/damage
Replace.
Thermostat
...
Installing the thermostat
1. Install:
Thermostat
NOTE:
Install the thermostat with its breather hole "a"
facing up.
2. Install:
Copper washer
Coolant temperature sensor
CAUTION:Use extreme care when ...
Other materials:
Checking the ignition timing
NOTE:
Prior to checking the ignition timing, check the
wiring connections of the entire ignition system.
Make sure all connections are tight and free of
corrosion.
1. Remove:
Rider seat
Left lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
Timing mark acces ...
Checking and replacing the rear wheel sprocket
1. Check:
Rear wheel sprocket
More than 1/4 tooth "a" wear
Replace the
rear wheel sprocket.
Bent teeth Replace the rear
wheel sprocket.
b. Correct
1. Drive chain roller
2. Rear wheel sprocket
2. Replace:
Rear wheel sprocket
a. Remove the self-locking nuts and the ...
Overheating
Engine
1. Clogged coolant passages
Cylinder head and piston
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Cooling system
1. Coolant
Low coolant level
2. Radiator
Damaged or leaking radiator
Faulty radiator cap
...