While the engine is cold, the thermostat is closed, the coolant circulates through the small circle of the cooling system (cylinder block and cylinder head); as the engine warms up, when the coolant temperature reaches approximately 85°C, the thermostat begins to open and part of the coolant circulates through a large circle of the cooling system (cylinder block, cylinder head and radiator). When the coolant temperature reaches approximately 95°C, the thermostat fully opens and all the liquid circulates through a large circle of the cooling system.
The check is carried out on a completely cooled down engine, at an ambient temperature of at least 20°C.
1. We start the engine.
2. In the process of warming up the engine by hand, we check the temperature of the upper radiator hose. If the hose warms up gradually, along with the engine warming up, then the thermostat is stuck in the open position. When engine temperature reaches 85-90°C (about the middle of the temperature gauge) the upper radiator hose should warm up quickly, indicating that the thermostat has opened. If this does not happen, then you need to drive a few kilometers (during the trip, check the readings of the temperature gauge), repeat the test. If there is no heating, then the thermostat is stuck in the closed position.
The thermostat is not repairable and must be replaced if it malfunctions.
Attention! The motorcycle must not be operated without a thermostat. When operating without a thermostat, the thermal regime of the engine is violated, the time for warming up the engine to operating temperature increases.