Yamaha YFM660 01 User Manual

							6 - 2
COOLRADIATOR
Order Job name/Part name Q’ty Remarks
11 Coolant reservoir 1
12 Coolant reservoir cap 1
For installation, reverse the removal pro-
cedure. 
						

							6 - 3
COOLRADIATOR
CHECKING THE RADIATOR
1.Check:

Radiator fins
Obstruction →
 Clean.
Apply compressed air to the rear of the radia-
tor.
Damage →
 Repair or replace.
OTE:
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.
***********************************************
Measurement steps:

Install the radiator cap tester 1
 and adapter
2
 onto the radiator cap 3
.

Apply the specified pressure for ten seconds
and make sure that there is no drop in pres-
sure.
***********************************************
4.Check:

Radiator fan
Damage →
 Replace.
Malfunction →
 Check and repair.
Refer to “COOLING SYSTEM” in CHAPTER
9.
Radiator cap opening pressure:
95 ~ 125 kPa 
(0.95 ~ 1.25 kg/cm
2, 
13.8 ~ 18.1 psi)
Radiator cap tester:
P/N. YU-24460-01, 90890-01325
Adapter:
P/N. YU-33984, 90890-01352 
						

							6 - 4
COOLRADIATOR
INSTALLING THE RADIATOR
1.Fill:

Cooling system
(with the specified amount of the recom-
mended coolant)
Refer to “CHANGING THE COOLANT” in
CHAPTER 3.
2.Check:

Cooling system
Leaks →
 Repair or replace any faulty part. 
						

							6 - 5
COOLTHERMOSTAT
THERMOSTAT
Order Job name/Part name Q’ty Remarks
Removing the thermostat
Remove the parts in the order below.
Front panel and front fender Refer to “SEAT, FENDERS AND FUEL 
TANK” in CHAPTER 3.
Coolant Drain.
Radiator Refer to “RADIATOR”.
1 Radiator inlet hose 1
2 Front fender bracket 1
3 Thermostat inlet hose 1
4 Water jacket outlet pipe 1
5 O-ring 1
6 Thermostat assembly 1
7 Thermo switch 2 1
For installation, reverse the removal pro-
cedure. 
						

							6 - 6
COOLTHERMOSTAT
Order Job name/Part name Q’ty Remarks
Disassembling the thermostat
Remove the parts in the order listed.
1
Thermostat cover 1
Refer to “ASSEMBLING THE THERMO-
STAT”. 2
O-ring 1
3
Thermostat 1
4
Thermostat housing 1
For assembly, reverse the disassembly 
procedure. 
						

							6 - 7
COOLTHERMOSTAT
CHECKING THE THERMOSTAT
1.Check:

Thermostat 1
 
Does not open at 69 ~ 73 °C (156.2 ~
163.4 °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.
***********************************************
1Thermostat
2Thermometer
3Water
4Container
ÈFully closed
ÉFully open
OTE:
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.
ASSEMBLING THE THERMOSTAT
1.Install:

Thermostat 1
 

Thermostat housing cover
OTE:
Install the thermostat with its breather hole a
toward the projection b
.
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. 
						

							6 - 8
COOLWATER PUMP
WATER PUMP
Order Job name/Part name Q’ty Remarks
Removing the water pump
Remove the parts in the order below.
Coolant Drain.
1 Radiator outlet hose 1 Disconnect.
2 Water pump outlet hose 1
3 Water pump assembly 1
4 O-ring 1
5 Water jacket inlet housing 1
6 O-ring 1
For installation, reverse the removal pro-
cedure. 
						

							6 - 9
COOLWATER PUMP
Order Job name/Part name Q’ty Remarks
Disassembling the water pump
Remove the parts in the order below.
1
Water pump housing cover 1
2
O-ring 1
3
Circlip 1
4
Impeller shaft gear 1
5
Pin 1
6
Circlip 1
7
Impeller 1
Refer to “DISASSEMBLING/ASSEM-
BLING THE THERMOSTAT”. 8
Impeller shaft 1
9
Rubber damper holder 1 
						

							6 - 10
COOLWATER PUMP
Order Job name/Part name Q’ty Remarks
0
Rubber damper 1
Refer to “DISASSEMBLING/ASSEM-
BLING THE THERMOSTAT”. A
Water pump seal 1
B
Oil seal 1
C
Bearing 1
D
Water pump housing 1
For assembly, reverse the disassembly 
procedure. 
						

							6 - 11
COOLWATER PUMP
DISASSEMBLING THE WATER PUMP
1.Remove:

Impeller shaft 1
 
OTE:
Tap out the impeller shaft from the impeller.
2.Remove:

Rubber damper holder 1
 

Rubber damper 2
 
(from the impeller, with a thin, flathead
screwdriver)
OTE:
Do not scratch the impeller.
3.Remove:

Water pump seal 1
 
OTE:
Tap out the water pump seal from the inside of
the water pump housing.
2Water pump housing
4.Remove:

Oil seal 1
 

Bearing 2
 
OTE:
Tap out the bearing and oil seal from the out-
side of the water pump housing.
3Water pump housing
CHECKING THE WATER PUMP
1.Check:

Water pump housing cover 1
 

Water pump housing 2
 

Impeller 3
 

Impeller shaft 4
 

Rubber damper 5
 

Rubber damper holder 6
 
Cracks/damage/wear →
 Replace.