Yamaha YFM660FS, Supplementary Service Manual

Page: 316 / 478

5 - 6
COOL
THERMOSTAT
CHECKING THE THERMOSTAT
1.Check:
●
Thermostat
1
Does not open at 50 ~ 54 °C (122 ~ 158 °F)
→
Replace.
*****************************************************
Checking steps:
●
Suspend the thermostat in a container filled
with water.
●
Slowly heat the water.
●
Place a thermometer in the water.
●
While stirring the water, observe the thermo-
stat and thermometer’s indicated tempera-
ture.
*****************************************************
1
Thermostat
2
Thermometer
3
Water
4
Container
È
Fully closed
É
Fully open
NOTE:
If the accuracy of the thermostat is in doubt,
replace it. A faulty thermostat could cause seri-
ous overheating or overcooling.
2.Check:
●
Thermostat housing cover
●
Thermostat housing
Cracks/damage
→
Replace.
Temperature
Openin
g
INSTALLING THE THERMOSTAT
1.Install:
●
Thermostat
1
●
Thermostat housing cover
NOTE:
Install the thermostat with its breather hole
a
facing up.
2.Fill:
●
Cooling system
(with the specified amount of the recom-
mended coolant)
Refer to “CHANGING THE COOLANT” in
CHAPTER 3.
3.Check:
●
Cooling system
Leak
→
Repair or replace any faulty part.