Coolant Drain Bolt
Water Pump Impeller Bolt
Oil Cooler Bolts

N·m
8.4
9.0
9.8
5.9
9.8
12
5.9
12
12
11
11
9.8
12

14. MY Model
HG: Apply high-temperature grease.
L: Apply a non-permanent locking agent.
LG: Apply liquid gasket.
R: Replacement Parts
W: Apply water.
WL: Apply soap and water solution or rubber lubricant.

Torque
kgf·m
0.86
0.92
1.0
0.60
1.0
1.2
0.60
1.2
1.2
1.1
1.1
1.0
1.2

ft·lb
74 in·lb
80 in·lb
87 in·lb
52 in·lb
87 in·lb
106 in·lb
52 in·lb
106 in·lb
106 in·lb
97 in·lb
97 in·lb
87 in·lb
106 in·lb

Remarks

L

L
L
L

L

4-4 COOLING SYSTEM
Coolant Flow Chart

1. Radiator
2. Radiator Fan
3. Radiator Cap
4. Radiator Overflow Hose
5. Air Bleeder Hose
6. Reserve Tank
7. Reserve Tank Overflow Hose

8. Water Pump
9. Oil Cooler (MY Model)
10. Cylinder Jacket
11. Cylinder Head Jacket
12. Thermostat Housing
13. Hot Coolant
14. Cold Coolant

COOLING SYSTEM 4-5
Coolant Flow Chart
Permanent type antifreeze is used as a coolant to protect the cooling system from rust and corrosion. When the engine starts, the water pump turns and the coolant circulates.
The thermostat is a wax pellet type which opens or closes with coolant temperature changes. The
thermostat continuously changes its valve opening to keep the coolant temperature at the proper level.
When coolant temperature is less than 55°C (131°F), the thermostat closes so that the coolant flow
is restricted through the air bleeder hole, causing the engine to warm up more quickly. When coolant
temperature is more than 58  62°C (136  144°F), the thermostat opens and the coolant flows.
When the coolant temperature goes up beyond 100°C (212°F), the radiator fan relay conducts to
operate the radiator fan. The radiator fan draws air through the radiator core when there is not sufficient air flow such as at low speeds. This increases up the cooling action of the radiator. When the
coolant temperature is below 97.5°C (208°F), the fan relay opens and the radiator fan stops.
In this way, this system controls the engine temperature within narrow limits where the engine operates most efficiently even if the engine load varies.
The system is pressurized by the radiator cap to suppress boiling and the resultant air bubbles
which can cause engine overheating. As the engine warms up, the coolant in the radiator and the
water jacket expands. The excess coolant flows through the radiator cap and hose to the reserve tank
to be stored there temporarily. Conversely, as the engine cools down, the coolant in the radiator and
the water jacket contracts, and the stored coolant flows back to the radiator from the reserve tank.
The radiator cap has two valves. One is a pressure valve which holds the pressure in the system
when the engine is running. When the pressure exceeds 107.9  137.3 kPa (1.10  1.40 kgf/cm²,
15.6  19.9 psi), the pressure valve opens and releases the pressure to the reserve tank. As soon
as pressure escapes, the valve closes, and keeps the pressure at 107.9  137.3 kPa (1.10  1.40
kgf/cm², 15.6  19.9 psi). When the engine cools down, another small valve (vacuum valve) in the
cap opens. As the coolant cools, the coolant contracts to form a vacuum in the system. The vacuum
valve opens and allows the coolant from the reserve tank to enter the radiator.

4-6 COOLING SYSTEM
Specifications
Item
Coolant Provided when Shipping
Type (Recommended)

Color
Mixed Ratio
Freezing Point
Total Amount

Radiator Cap
Relief Pressure
Thermostat
Valve Opening Temperature
Valve Full Opening Lift

Standard
Permanent type of antifreeze (soft water and ethylene glycol
plus corrosion and rust inhibitor chemicals for aluminum
engines and radiators)
Green
Soft water 50%, coolant 50%
−35°C (−31°F)
2.4 L (2.5 US qt) (Reserve tank full level, including radiator
and engine)
(MY) 2.5 L (2.6 US qt) (Reserve tank full level, including
radiator and engine)
107.9  37.3 kPa (1.10  1.40 kgf/cm², 15.6  19.9 psi)
58  62°C (136  144°F)
8 mm (0.31 in.) or more @75°C (167°F)

COOLING SYSTEM 4-7
Special Tools and Sealant
Bearing Driver Set:
57001-1129

Oil Seal Driver
57001-1660

37.5:

Liquid Gasket, TB1211F:
92104-0004

4-8 COOLING SYSTEM
Coolant
Coolant Deterioration Inspection

inspect the coolant in the reserve tank [A].
• Visually
If whitish cotton-like wafts are observed, aluminum parts
in the cooling system are corroded. If the coolant is
brown, iron or steel parts are rusting. In either case, flush
the cooling system.
If the coolant gives off an abnormal smell, check for a
cooling system leak. It may be caused by exhaust gas
leaking into the cooling system.

Coolant Level Inspection

to the Coolant Level Inspection in the Periodic Main• Refer
tenance chapter.

Coolant Draining

to the Coolant Change in the Periodic Maintenance
• Refer
chapter.

Coolant Filling

to the Coolant Change in the Periodic Maintenance
• Refer
chapter.

Pressure Testing

the right inner cover (see Inner Cover Removal
• Remove
in the Frame chapter).
the radiator cap, and install a cooling system
• Remove
pressure tester [A] on the filler neck.

NOTE

○Wet the cap sealing surfaces with water or coolant to
prevent pressure leaks.
up pressure in the system carefully until the pres• Build
sure reaches 137.3 kPa (1.40 kgf/cm², 19.9 psi).

NOTICE
During pressure testing, do not exceed the pressure for which the system is designed. The maximum pressure is 137.3 kPa (1.40 kgf/cm², 19.9 psi).
the gauge for at least 6 seconds.
• Watch
If the pressure holds steady, the system is all right.

•
•

If the pressure drops and no external source is found,
check for internal leaks. Droplets in the engine oil indicate
internal leakage. Check the cylinder head gasket and the
water pump.
Remove the pressure tester, replenish the coolant, and
install the radiator cap.
Install the right inner cover (see Inner Cover Installation
in the Frame chapter).

COOLING SYSTEM 4-9
Coolant
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency of the cooling system.
Drain the cooling system (see Coolant Change in the Periodic Maintenance chapter).
Fill the cooling system with fresh water mixed with a flushing compound.

•
•

NOTICE
Do not use a flushing compound which is harmful to
the aluminum engine and radiator. Carefully follow
the instructions supplied by the manufacturer of the
cleaning product.
up the engine, and run it at normal operating tem• Warm
perature for about ten minutes.
the engine, and drain the cooling system.
• Stop
Fill
the
with fresh water.
• Warm upsystem
the
engine
and drain the system.
• Repeat the previous two
steps once more.
• Fill the system with a permanent
type coolant and bleed
• the air from the system (see Coolant
Change in the Periodic Maintenance chapter).

Coolant Reserve Tank Removal

the coolant (see Coolant Change in the Periodic
• Drain
Maintenance chapter).
the throttle body assy (see Throttle Body Assy
• Remove
Removal in the Fuel System (DFI) chapter).
the clamp [A] and disconnect the radiator overflow
• Slide
hose [B].

the water temperature sensor connector [A].
• Disconnect
Remove:
• Coolant Reserve Tank Bolt [B]
Coolant Reserve Tank [C]

Coolant Reserve Tank Installation

a non-permanent locking agent to the threads of
• Apply
the coolant reserve tank bolt and tighten them.
• Install the removed parts (see appropriate chapters).

4-10 COOLING SYSTEM
Water Pump
Water Pump Removal

• Drain:
Coolant (see Coolant Change in the Periodic Mainte•
•
•

nance chapter)
Engine Oil (see Engine Oil Change in the Periodic Maintenance chapter)
Remove:
Left Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Engine Sprocket Cover (see Engine Sprocket in the Final Drive chapter)
Remove the water pipe bolts [A], and disconnect the water
pipes [B].
For MY model, slide the water hose clamp [C], and disconnect the water hose [D].

• Remove:
Water Pump Cover Bolts [A]
Clamp [B]
Water Pump Cover [C]

• Remove:
Water Pump Impeller Bolt [A] and Washer
Water Pump Impeller [B]
Water Pump Housing [C]

Water Pump Installation

• Replace the O-ring [A] with a new one, and install it.

COOLING SYSTEM 4-11
Water Pump

• Be sure to install the dowel pins [A].

• Install:
Water Pump Housing [A]
•
•

Water Pump Impeller [B]
Replace the washer with a new one, and install it.
Tighten:
Torque - Water Pump Impeller Bolt [C]: 9.8 N·m (1.0 kgf·m,
87 in·lb)

• Be sure to install the dowel pins [D].
• Replace the O-ring [A] with a new one, and install it.

• Install:
Water Pump Cover [A]
Clamp [B]

○Install the clamp so that fit the stopper of the water pump

•

cover.
Tighten:
Torque - Water Pump Cover Bolts [C]: 11 N·m (1.1 kgf·m, 97
in·lb)

the O-rings [D] with new ones.
• Replace
Apply
soap
and water solution to the O-rings.
•
the water pipes [A] to the water pump cover.
• Install
a non-permanent locking agent to the threads of
• Apply
the water pipe bolts [B], and tighten them.
Torque - Water Pipe Bolts: 12 N·m (1.2 kgf·m, 106 in·lb)

MY model, install the water hose [C] and clamp [D]
• For
(see Cable, Wire, and Hose Routing section in the Ap-

•

pendix chapter).
Install the removed parts (see appropriate chapters).

4-12 COOLING SYSTEM
Water Pump
Water Pump Inspection

the drainage outlet passage [A] at the bottom of
• Check
the water pump housing for coolant leaks.
a coolant leak or ooze is found, start the engine and
• Ifcheck
if the coolant leaks continuously.

○When coolant does not continuously leak, it is normal.

If the mechanical seal is damaged, the coolant continuously leaks through the drainage outlet passage. Replace
the mechanical seal unit.
If the oil seal is damaged, engine oil leaks through the
drainage outlet passage. Replace the oil seal.

Water Pump Impeller Disassembly/Assembly

the water pump impeller (see Water Pump Re• Remove
moval).
sealing seat [A] and rubber seal [B] may be removed
• The
easily by hand.
water or coolant around the surfaces of the rubber
• Apply
seal and sealing seat.
the rubber seal and sealing seat into the impeller by
• Install
pressing them by hand until the seat stops at the bottom

•

of the hole.
Install the water pump impeller (see Water Pump Installation).

Water Pump Impeller Inspection

the water pump cover (see Water Pump Re• Remove
moval).
inspect the water pump impeller [A].
• Visually
If the surface is corroded or if the blades are damaged,
replace the water pump impeller.

Water Pump Housing Disassembly
NOTICE
Do not damage the hole wall of the water pump
housing.
a bar [A] into the pump housing [B], and hammer
• Insert
evenly around the circumference of the mechanical seal
bottom [C].

COOLING SYSTEM 4-13
Water Pump

• Take the oil seal [A] out of the housing [B] with a hook [C].

Water Pump Housing Assembly
NOTICE
Do not reuse the mechanical seal and oil seal.
high-temperature grease to the oil seal lips [A].
• Apply
Press
the new oil seal into the housing with a bearing
• driver [B]
until it stops at the bottom surface [C] of the
housing.
Special Tool - Bearing Driver Set: 57001-1129

NOTICE
Be careful not to damage the sealing surface of the
mechanical seal.
the new mechanical seal into the housing with the
• Press
oil seal driver [A] until its flange [B] touches the surface
[C] of the housing.
Special Tool - Oil Seal Driver

37.5: 57001-1660

Mechanical Seal Inspection

the water pump impeller (see Water Pump Re• Remove
moval).
inspect the mechanical seal.
• Visually
If any one of the parts is damaged, replace the mechanical seal as a unit.
Impeller Sealing Seat Surface [A]
Rubber Seal [B]
Mechanical Seal [C]

4-14 COOLING SYSTEM
Radiator
Radiator and Radiator Fan Removal

the coolant (see Coolant change in the Periodic
• Drain
Maintenance chapter).
the air cleaner housing (see Air Cleaner Housing
• Remove
Removal in the Fuel System (DFI) chapter).
• Disconnect the radiator fan motor lead connector [A].

the clamp [A].
• Slide
Disconnect
the water hose [B].
•

the clutch cable [A] from the guide [B].
• Free
Slide
the clamps [C].
• Disconnect:
• Water Hose [D]
Radiator Overflow Hose [E]
Air Bleeder Hose [F]

• Remove:
Radiator Mounting Bolts [A]
Radiator [B]

• Remove:
Radiator Fan Mounting Bolts [A]
Radiator Fan [B]

COOLING SYSTEM 4-15
Radiator
Radiator and Radiator Fan Installation
is the reverse of removal.
• Installation
• Install the radiator fan to the radiator.

Torque - Radiator Fan Mounting Bolts: 8.4 N·m (0.86 kgf·m,
74 in·lb)

the rubber dampers [A] and radiator bracket collars
• Install
[B] as shown.
Larger [C]
Smaller [D]

the radiator.
• Install
Run
the
fan motor lead correctly (see Cable,
• Wire, andradiator
Hose Routing section in the Appendix chapter).
Install
the
water hoses and clamps (see Cable, Wire, and
• Hose Routing
section in the Appendix chapter).
Install
the
removed
parts (see appropriate chapters).
•

Radiator Inspection

special edition model, remove the radiator guard (see
• For
Radiator Guard Removal in the Frame chapter).
the radiator (see Radiator and Radiator Fan Re• Remove
moval).
the radiator core.
• Check
If there are obstructions to air flow, remove them.
If the corrugated fins [A] are deformed, carefully
straighten them.
If the air passages of the radiator core are blocked more
than 20% by unremovable obstructions or irreparably deformed fins, replace the radiator with a new one.

4-16 COOLING SYSTEM
Radiator
NOTICE
When cleaning the radiator with steam cleaner, be
careful of the following to prevent radiator damage:
Keep the steam gun [A] away more than 0.5 m (1.6
ft) [B] from the radiator core.
Hold the steam gun perpendicular [C] (not oblique
[D]) to the core surface.
Run the steam gun, following the core fin direction.

Radiator Cap Inspection

• Remove:
Right Inner Cover (see Inner Cover Removal in the
•

Frame chapter)
Radiator Cap
Check the condition of the bottom [A] and top [B] valve
seals and valve spring [C].
If any one of them shows visible damage, replace the cap
with a new one.

• Install the cap [A] on a cooling system pressure tester [B].
NOTE

○Wet the cap sealing surfaces with water or coolant to
prevent pressure leaks.
the pressure gauge, pump the pressure tester
• Watching
to build up the pressure until the relief valve opens: the
gauge needle flicks downward. Stop pumping and measure leak time at once. The relief valve must open within
the specified range in the table below and the gauge hand
must remain within the same range at least 6 seconds.
Radiator Cap Relief Pressure
Standard: 107.9  137.3 kPa (1.10  1.40 kgf/cm², 15.6
 19.9 psi)

If the cap can not hold the specified pressure or if it holds
too much pressure, replace it with a new one.

Radiator Filler Neck Inspection

• Remove: