If your bike boils without the fan runs.
When the engine runs, pull the two electric connectors from the thermostat in the bottom of the right radiator.
Make contact with the two connectors, if the fan runs, the thermostat is broken.
If it doesn't run, either the fan has no power or something has been restricting the fan blade from turning.
If you want to check the function of the thermostat, empty the cooling fluid,
Pull the connectors of the thermostat and screw it off of the radiator, place the thermostat in a pot with water on the stove, add a thermometer in the water. Connect a multimeter to the two connectors on the thermostat, measure the resistance. While boiling the water, check the water temperature so you will know at what temperature the thermostat closes the circuit.
