Checking The Thermostat; Installing The Thermostat - Yamaha YFM70RY Service Manual

EAS26450

CHECKING THE THERMOSTAT

1. Check:
• Thermostat "1"
Does not open at 69–73 °C (156.2–163.4 °F)
→ Replace.
M MMM M MMM M M MMM M
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 thermo-
stat and thermometer's indicated tempera-
ture.
A. Fully closed
B. Fully open
TIP
If the accuracy of the thermostat is in doubt, re-
place it. A faulty thermostat could cause serious
overheating or overcooling.
L LLL L LLL L L LLL L
M MMM M M MMM M M MMM M
L LLL L L LLL L L LLL L
2. Check:
• Thermostat cover
• Thermostat housing (cylinder head)
Cracks/damage → Replace.
EAS1S3L009

INSTALLING THE THERMOSTAT

1. Install:
• Thermostat "1"
• O-ring "2"
• Thermostat cover "3"
TIP
Install the thermostat with its breather hole "a"
facing up.
MMM
2. Fill:
• Cooling system
(with the specified amount of the recom-
mended coolant)
Refer to "CHANGING THE COOLANT" on
page 3-18.
3. Check:
• Cooling system
Leak → Repair or replace any faulty part.
LLL
6-4
THERMOSTAT
New
a
2
3 New
1