Cooling system
Checking the thermostat
In this manual: Cooling system
~1min read
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.
Test yourself
A quick Yamaha YZF-R125 quiz: every answer comes with an explanation and a link to the manual page.
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