12. COOLING SYSTEM
12-0
Mongo ose/KXR 250
12
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
COOLING SYSTEM
__________________________________________________________________________________
SERVICE INFORMATION -------------------------------------------- 12- 1
TROUBLESHOOTING ------------------------------------------------- 12- 1
COOLING SYSTEM TESTING --------------------------------------- 12- 3
RADIATOR -------------------------------------------------------------- 12- 4
WATER PUMP ---------------------------------------------------------- 12- 6
THERMOSENSOR ------------------------------------------------------ 12-10
THERMOSTAT---------------------------------------------------------- 12-11
12
12. COOLING SYSTEM
12-1
Mongo ose/KXR 250
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The water pump must be serviced after removing the engine.
Other cooling system service can be done with the engine installed in the frame.
• The engine must be cool before servicing the cooling system.
When the coolant temperature is over 100¢J, never remove the radiator cap to release the
pressure because the boiling coolant may cause danger.
• Avoid spilling coolant on painted surfaces because the coolant will corrode the painted surfaces.
Wash off any spilled coolant with fresh water as soon as possible.
• After servicing the system, check for leaks with a cooling system tester.
SPECIAL TOOL
Mechanical seal driver
TORQUE VALUES
Water pump impeller 1.0_ 1.4kgf-m
Water pump cover bolt 0.8_ 1.2kgf-m
TROUBLESHOOTING
Engine temperature too high Coolant leaks
• Faulty temperature gauge or thermosensor • Faulty pump mechanical (water) seal
• Faulty radiator cap • Deteriorated O-rings
• Faulty thermostat • Damaged or deteriorated water hoses
• Insufficient coolant
• Passages blocked in hoses or water jacket
• Clogged radiator fins
• Passages blocked in radiator
• Faulty water pump
Temperature gauge pointer does not register
the correct coolant temperature
• Faulty temperature gauge or thermosensor
• Faulty thermostat
12. COOLING SYSTEM
12-2
Mongo ose/KXR 250
SPECIFICATIONS
Radiator cap relief pressure
075~1.05kg/cm_
Begins to open
80±2¢J
Thermostat temperature
Full-open
90¢J
Valve lift
3.5_ 4.5mm
Coolant capacity
Total system 1400±20cc
Radiator: 1100±20cc
Reserve tank: 300±20cc
COOLANT GRAVITY
Temp. ¢J
Coolant
concentration
05101520253035404550
5%
1.009
1.009
1.008
1.008
1.007
1.006
1.005
1.003
1.001
0.009
0.997
10%
1.018
1.107
1.017
1.016
1.015
1.014
0.013
1.011
1.009
1.007
1.005
15%
1.028
1.027
1.026
1.025
1.024
1.022
1.020
1.018
1.016
1.014
1.012
20%
1.036
1.035
1.034
1.033
1.031
1.029
1.027
1.025
1.023
1.021
1.019
25%
1.045
1.044
1.043
1.042
1.040
1.038
1.036
1.034
1.031
1.028
1.025
30%
1.053
1.051
1.051
1.049
1.047
1.045
1.043
1.041
1.038
1.035
1.032
35%
1.063
1.062
1.060
1.058
1.056
1.054
1.052
1.049
1.046
1.043
1.040
40%
1.072
1.070
1.068
1.066
1.064
1.062
1.059
1.056
1.053
1.050
1.047
45%
1.080
1.078
1.076
1.074
1.072
1.069
1.056
1.063
1.062
1.057
1.054
50%
1.086
1.084
1.082
1.080
1.077
1.074
1.071
1.068
1.065
1.062
1.059
55%
1.095
1.093
1.091
1.088
1.085
1.082
1.079
1.076
1.073
1.070
1.067
60%
1.100
1.098
1.095
1.092
1.089
1.086
1.083
1.080
1.077
1.074
1.071
COOLANT MIXTURE (WITH ANTI-RUST AND ANTI-FREEZING EFFECTS)
Freezing Point
Mixing Rate
KYMCO SIGMA Coolant Concentrate
Distilled Water
-9¢J
20%
-15¢J
30%
425cc
975cc
-25¢J
40%
-37¢J
50%
-44.5¢J
55%
Cautions for Using Coolant:
• Use coolant of specified mixing rate. (The
mixing rate of 425cc KYMCO SIGMA
coolant concentrate + 975cc distilled
water is 30%.)
• Do not mix coolant concentrate of
different brands.
• Do not drink the coolant which is
poisonous.
• The freezing point of coolant mixture shall
be 5¢Jlower than the freezing point of the
riding area.
12. COOLING SYSTEM
12-3
Mongo ose/KXR 250
COOLING SYSTEM TESTING
RADIATOR CAP INSPECTION
Install the radiator cap onto the radiator
tester and apply specified pressure to it. It
must hold specified pressure for at least six
seconds.
Radiator Cap Relief Pressure:
0.75~1.05kg/cm_
Install the radiator tester onto the radiator
and apply specified pressure to it. It must
hold specified pressure for at least six
seconds.
Check the water hoses and connectors for
leaks.
The test pressure should not exceed 1.05
kg/cm_. Excessive pressure can damage
the radiator and its hose connectors.
°Ø
Apply water to the cap sealing surface
before testing.
°Ø
Radiator Cap
Radiator Tester
12. COOLING SYSTEM
12-4
Mongo ose/KXR 250
RADIATOR
RADIATOR INSPECTION
Remove the front fender. (!2-5)
Inspect the radiator soldered joints and
seams for leaks.
Blow dirt out from between core fins with
compressed air. If insects, etc., are clogging
the radiator, wash them off.
Carefully straighten any bent fins.
RADIATOR REMOVAL
Drain the coolant. (!3-20)
Remove the front fender. (!2-5)
Disconnect the air vent tube from the
radiator filler.
Remove the overflow tube clamp and
disconnect the overflow tube.
Disconnect the fan motor wire coupler.
Remove the two bolts on the radiator filler
hold plate.
Remove the two bolts on the radiator.
Disconnect the thermostatic switch wire
leads.
Loosen the hose bands and disconnect the
upper hose and lower hose from the
radiator.
Pull the radiator upward to remove the
radiator.
Radiator
Air Vent Tube
Overflow Tube
Fan Motor Coupler
Bolts
Bolts
Thermostatic Switch Lead
Upper Hose
Lower Hose
12. COOLING SYSTEM
12-5
Mongo ose/KXR 250
RADIATOR DISASSEMBLY
Remove the three bolts and then remove the
fan/shroud from the radiator.
Check fan motor by battery.
CHECK THERMOSTATIC SWITCH
When coolant temperature lower then
85~90¢J the thermostatic switch OFF.
When coolant temperature over 85~90¢J
the thermostatic switch ON.
RADIATOR ASSEMBLY
Install the fan shroud on the radiator with
the three bolts.
RADIATOR INSTALLATION
Reverse the “RADIATOR REMOVAL”
procedures.
Fill the radiator with coolant. (!3-20)
Connect the vent tube to the radiator filler.
After installation, check for coolant leaks.
Bolts
If you want to refill the coolant , the
following procedure must be checked.
1. Please make the radiator filler and the
air vent tube to be separated.
2. Then start the engine , filled in the
coolant till the coolant flowed out
from the air vent tube.
3. Put the air vent tube on.
°Ø
Thermostatic Switch
12. COOLING SYSTEM
12-6
Mongo ose/KXR 250
WATER PUMP
MECHANICAL SEAL (WATER SEAL)
INSPECTION
Inspect the
telltale hole for signs of
mechanical seal coolant leakage.
If the mechanical seal is leaking, remove the
right crankcase cover and replace the
mechanical seal.
WATER PUMP/IMPELLER REMOVAL
Drain the coolant. (!3-20)
Loosen the screw and disconnect the
coolant inlet hose.
Remove the four bolts and the water pump
cover.
Remove the gasket and 2 dowel pins
Remove the water pump impeller, washer
and seal washer (porcelain).
Telltale Hole
Water Pump
Inlet Hose
Bolts
Water Pump Cover
Water Pump Impeller
Gasket
Dowel Pins
The impeller has left hand threads.
°Ø
12. COOLING SYSTEM
12-7
Mongo ose/KXR 250
Inspect the mechanical (water) seal and seal
washer for wear or damage.
WATER PUMP SHAFT REMOVAL
Remove the water pump impeller. (
!12-6
)
Disconnect the water hose from the right
crankcase cover.
Remove the twelve bolts attaching the right
crankcase cover.
Remove the water pump bearing snap ring
from the water pump assembly.
Remove the water pump shaft and inner
bearing.
Mechanical Seal
Seal Washer (Porcelain)
Impeller
The mechanical seal and seal washer
must be replace as a set.
°Ø
Snap Ring
Inner Bearing
Water Pump Shaft
12. COOLING SYSTEM
12-8
Mongo ose/KXR 250
Water Pump Assembly
Remove the water pump shaft outer
bearing.
MECHANICAL SEAL REPLACEMENT
Drive the mechanical seal out of the water
pump assembly from the inside.
Drive in a new mechanical seal using a
mechanical seal driver.
Inner Bearing
Apply sealant to the right crankcase
cover fitting surface of a new mechanical
seal and then drive in the mechanical seal.
°Ø
Mechanical Seal (Water
Snap Ring
Outer Bearing
Water Pump Shaft
Washer
Impeller
Seal Washer
12. COOLING SYSTEM
12-9
Mongo ose/KXR 250
WATER PUMP S HAFT INSTALLATION
Drive a new water pump shaft
outer bearing
into the water pump assembly from the
inside.
Install the water pump shaft and shaft inner
bearing into the waster pump assembly.
Install the snap ring to secure the inner
bearing properly.
Install the dowel pins and a new gasket and
then install the water pump assembly to the
right crankcase cover.
Tighten the twelve bolts to secure the right
crankcase cover.
WATER PUMP/IMPELLER
INSTALLATION
When the mechanical seal is replaced, a new
seal washer must be installed to the
impeller.
Install the impeller onto the water pump
shaft.
Torque: 1.0_ 1.4kgf-m
Install the two dowel pins and a new
gasket.
Install the water pump cover and tighten
the four bolts.
Torque: 0.8_ 1.2 kgf-m
When installing the water pump
assembly, aligning the groove on the
water pump shaft with the tab on the oil
pump shaft.
°Ø
The impeller has left hand threads.
°Ø
Water Pump Assembly
Outer Bearing
12. COOLING SYSTEM
12-10
Mongo ose/KXR 250
THERMOSENSOR
THERMOSENSOR REMOVAL
Drain the coolant. (
!3-20
)
Disconnect the thermosensor wire.
Remove the thermosensor from the
thermostat.
THERMOSENSOR INSPECTION
Suspend the thermosensor in a pan of water
over a burner and measure the resistance
through the sensor as the water heats up.
Temperature(¢J)
5080100
120
Resistance(W)
1545227
16
THERMOSENSOR INSTALLATION
Apply 3-BOND No. 1212 sealant or
equivalent to the thermosensor threads and
install it into the thermostat housing.
Connect the thermosensor wire.
Fill the radiator with coolant. (!3-20)
Thermosensor Wire
Thermosensor
Be sure to bleed air from the cooling
system.
°Ø
12. COOLING SYSTEM
12-11
Mongo ose/KXR 250
THERMOSTAT
THERMOSTAT REMOVAL
Drain the coolant. (!3-20)
Disconnect the thermosensor wire from the
thermosensor.
Disconnect the water hose from the
thermostat housing.
Disconnect the air vent tube from the
thermostat housing.
Remove the mounting bolt and the
thermostat housing from the cylinder head.
Remove the two screws and separate the
thermostat housing halves.
Remove the thermostat from the thermostat
housing.
Thermostat
Bolts
Thermostat
Bolts
Air Vent Tube
Water Hose
Thermostat
12. COOLING SYSTEM
12-12
Mongo ose/KXR 250
THERMOSTAT INSPECTION
Suspend the thermostat in a pan of water
over a burner and gradually raise the water
temperature to check its operation.
Technical Data
Begins to open
80±2¢J
Full-open
90¢J
Valve lift
3.5_ 4.5mm
THERMOSTAT INSTALLATION
The installation sequence is the reverse of
removal.
Fill the cooling system with the specified
coolant. (!3-20)
O-ring
Thermosensor
Thermostat
Thermometer
• Do not let the thermostat touch the pan
as it will give a false reading.
• Replace the thermostat if the valve
stays open at room temperature.
•Test the thermostat after it is opened
for about 5 minutes and holds the
temperature at 70¢J .
°Ø
Replace the O-ring with a new one and
apply grease to it.
°Ø
Loading...