1. Radiator
2. Radiator Fan
3. Water Pump
4. Oil Cooler
5. Oil Cooler Intake Hose
6. Oil Cooler Outlet Hose
7. Cylinder Jacket
8. Cylinder Head Jacket
9. Thermostat Housing
10. Air Bleeder Hose
11. Radiator Cap
12. Radiator Overflow Hose
13. Reserve Tank
14. Reserve Tank Overflow Hose
15. Hot Coolant
16. Cold Coolant
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 95°C (203°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 90°C (194°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 112
142 kPa (1.14
1.45 kgf/cm², 16
21
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 112
142 kPa (1.14
1.45 kgf/cm², 16
21 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.
Specifications
Special Tools
Bearing Driver Set:
57001-1129
Oil Seal Driver 37.5:
57001-1660
Air Switching Valve (Service Code 64)
Air Switching Valve Removal/Installation
Refer to the Air Switching Valve Removal/Installation in
the Engine Top End chapter.
Air Switching Valve Inspection
Refer to the Air Switching Valve Unit Test in the Electrical
System chapter.
If the air switching valve [A] is normal, check ...
Troubleshooting Guide
NOTE
Refer to the Fuel System chapter for most
of DFI trouble shooting guide.
This is not an exhaustive list, giving every
possible cause for each problem listed. It
is meant simply as a rough guide to assist
the troubleshooting for some of the more
common difficulties.
Engine Doe ...
General Information
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in a retrieval system, or
transmitted in any form or by any means, electronic mechanical photocopying,
recording or otherwise,
without the prior written permission of Quality Assurance Division/Motorcycle &
Engin ...