Like this Manual?SAFETY FIRST: Antifreeze is highly toxic and can kill pets and animals if drank. Do not leave coolant where animals (including children!) can get to it.
SAFETY FIRST: Protective gloves and eyewear are recommended at this point.
Removal
Drain the coolant. See the Coolant topic for more information.
Remove the front fender. See the Front Fender topic for more information.
Remove the four thermostat cover bolts.
Remove the thermostat housing cover and thermostat. Inspect the O-ring seal and replace it as needed.
Inspection
Inspect the thermostat valve at room temperature, if the valve is open the thermostat is defective and needs to be replaced.
To check the thermostat opening temperature, fill a pan with tap water and suspend the thermostat with a piece of wire, completely immersing it in the water making sure the thermostat does not touch the pan.
Place a thermometer in the pan and heat the water on a burner. Gently stir the water and notice what the temperature is when the thermostat starts to open.
| Item | Standard |
| Valve opening temperature | 69.5 ~ 72.5°C (157 ~ 162°F) |
| Valve full opening lift | 8 mm or more @ 85°C (185°F) |
Installation
Place a new O-ring on the thermostat cover.
Fit the thermostat into place.
Install the thermostat cover and mounting bolts. Be sure to install the ground wire. Tighten the four thermostat cover bolts to specification with an 8 mm socket.
| Fastener | Torque | ||
| N-m | kgf-m | ft-lb | |
| Thermostat housing cover bolts | 8.8 | 0.9 | 78 in-lb |
Fill the coolant. See the Coolant topic for more information.
Install the front fender. See the Front Fender topic for more information.
Water Temperature Switch
The water temperature switch is located on the thermostat housing.
Test the water temperature switch in a container of coolant as with the thermostat. Use a digital multimeter set to ohms of resistance.
| Item | Standard |
| Coolant temperature warning light switch (WTS) resistance: | ON: less than 0.5 Ω OFF: More than 1 MΩ |
| Rising temperature | From OFF to ON at 112- 118°C (234 ~ 244°F) |
| Falling temperature | From ON to OFF at 108 ~ 111°C (226 ~ 232°F) |
If the switch needs to be replaced tighten the new switch to specification.
| Fastener | Torque | ||
| N-m | kgf-m | ft-lb | |
| Coolant temperature warning light switch [2002 – 2003] | 7.9 | 0.8 | 69 in-lb |
| Coolant temperature warning light switch [2005 – 2006] | 6.9 | 0.70 | 61 in-lb |
| Water temperature switch (WTS) [700cc] | 7.8 | 0.80 | 69 in-lb |
Coolant Valve
The coolant valve is located on the right side of the engine. Its hoses connect to the water pump on the bottom and the carburetors on the top.
To inspect the coolant valve drain the coolant and remove the coolant valve. See the Coolant topic for more information.
Check and see if the valve is open or closed. The valve should be open at room temperature.
| Coolant valve closing temperature | Standard |
| 700cc | 70°C (158°F) or more at 25kPa (0.25 kgf/cm2, 3.6 psi) |
| 650cc | 65°C (149°F) or more at 25 kPa (0.25 kgf/cm2, 3.6 psi) [2002 – 2003] |
| 78 ~ 82°C (172 ~180°F) or more at 24.5 kPa (0.25 kgf/cm2, 3.6 psi) [2005 – 2011] |
Replace the valve if is open when it should not be.