(1) What are the conditions that cause the overheating of the water-cooled vehicle engine?

Thermostat malfunctioning, unable to control coolant temperature

The cooling system is clogged and the coolant cannot circulate effectively

Insufficient coolant stock or a leak in the cooling system resulting in too little coolant

The temperature control switch and fan motor are faulty, resulting in poor heat dissipation

The suction capacity of the water pump is reduced, and the coolant circulation is insufficient

(2) Under what circumstances will the water-cooled motorcycle strike?

(1) The mixture concentration is too lean

If the mixture concentration of the carburetor has been adjusted by professionals with special equipment when leaving the factory, the user does not need to adjust it. If it is determined that the mixture concentration is too thin and causes overheating, it is necessary to adjust the carburetor adjusting screw appropriately.

(2) The circulation system is blocked

Check the circulatory system for blockages. The radiator should be cleaned with water tank cleaning agent every 5000km, and special attention should be paid to whether the small circulating water pipe is twisted or blocked.

Because the small circulation is not smooth, when the engine starts, the temperature of the coolant in the water jacket of the cylinder head continues to rise but cannot circulate, the water temperature at the thermostat cannot rise, the thermostat cannot be opened, and when the water in the water jacket When the temperature rises above the boiling point, with the intensification of molecular motion, the water temperature at the thermostat gradually rises, the thermostat is opened, and the high-temperature and high-pressure water flow in the water jacket rushes out of the water inlet cover, resulting in the phenomenon of "opening the pot".

(3) The thermostat is not working well

The seat cushion and side panels are all covering parts for the forced air-cooled engine purchased in the market, and the heat insulation performance does not meet the requirements. Riders often feel that the seat cushion and partition are hot, which is more obvious in summer. , that is, it is mistaken for the engine to be overheated. The function of the thermostat is to reduce the amount of coolant circulation after the cold car starts, so that the engine can reach the optimal operating temperature (about 80 ° C ~ 95 ° C) as soon as possible.

The authentic wax thermostat should start to open when the coolant temperature is about 70°C, and reach full opening at about 80°C. If the thermostat cannot be opened normally, it will inevitably lead to poor circulation and overheating of the engine. In addition, the water filler cap will fail. , the lack of water in the auxiliary water tank will also cause insufficient coolant in the circulating system, resulting in overheating. Other reasons similar to the air-cooled engine will not be repeated. In fact, as long as the water-cooled engine does not "boil the pot", it will never be overheated, because even when the coolant is boiled, the temperature of the cylinder head will not exceed 120 ℃, which is much lower than the general air-cooled engine.

(4) Insufficient or leaking coolant

When the car is cold, open the water filler cap next to the radiator to check whether the coolant is sufficient. The coolant should be filled up from the water filler at idling speed. The coolant in the reservoir only needs to be supplemented to about 2 of the total capacity. At /3, check whether the engine oil is emulsified and deteriorated. If the oil is emulsified and turned white, it means that the coolant is leaking.

Under normal circumstances, the internal leakage mainly occurs at the junction of the cylinder head and the cylinder block, which can be solved by replacing the cylinder mattress. The preparation of the coolant varies with the area of ​​use and the concentration of the original liquid. The following table takes Honda Super Coolant as an example: In addition, carefully check whether the water pipe joints are leaking, whether the water pipes are damaged, and whether there is water leakage from the leaking holes of the water pump.

(5) The valve clearance is too small

The exhaust valve clearance is required to be 0.10mm. However, due to the excessive size of components in domestic engines or the user’s unacceptable valve noise, many domestic manufacturers adjust the engine valve to a small size when the product (or user) leaves the factory, causing the valve to close. If it is not strict, it is possible to prolong the supplementary combustion period of the mixture combustion, and a large part of the heat emitted during the supplementary combustion period is used to do work for heating up, thus causing the engine to overheat.

In order to ensure the performance of the engine, the valve clearance has certain requirements, not as small as possible. In fact, as long as the valve clearance is adjusted according to the requirements, a slight valve noise will not affect the use. We have done a comparative test, adjusting the valve clearance according to the regulations and adjusting the valve clearance to a small value, the difference between the maximum power of the engine is nearly 30%.