Recently receive repair a big Yang DY125 straddle riding motorcycle, the owner said recently fuel consumption odd high, 100 kilometers 3 liters more, the oil price is so high, motorcycle quickly can not afford to use.
Usually high fuel consumption and mixing ratio is not related to the larger, mixed gas concentration, combustion is not complete, at this time the typical symptom is the spark plug carbon accumulation, big throttle exhaust pipe black smoke. Another reason may be the poor ignition of the igniter, resulting in the mixture is not fully burned.
After the start of the test run, feel the engine work is normal, no such as engine start-up difficulties, idle operation instability, easy to stall, motorcycle driving weakness and other fault phenomena. I didn't see any black smoke on the throttle.
Since there are no obvious running failures, it's a static check to see what's wrong. Prop up the big support, first check the oil circuit, this car is frequently used, the engine is dirty, check to the carburetor, found that the carburetor outside the oil is dirty, the mixture of oil and mud covered with a thick layer, obviously see the oil leak like, the oil spot on the mud is obvious. Combined with the normal operation of the engine, the reason for the high fuel consumption of the car is likely to be a carburetor oil leak.
Carburetor oil leakage fault, usually caused by the triangle needle valve is not strictly closed, carburetor oil leakage fault, the oil and water plane in the float room will rise abnormally, carburetor to provide the engine with the combustible mixture will be too thick, will affect the normal work of the engine. But after the test run just now, the start of the motorcycle running are very normal, which shows that the fault with a certain particularity.
Remove THE CARBURETOR FROM THE engine FOR inspection, use gasoline to clean the CARBUREtor outside, and then decompose the CARBUREtor, check the triangle needle and needle seat, oil float working height, confirm that the triangle needle valve is closed well, oil float working height is normal, it is impossible to occur abnormal oil plane rise.
The oil plane is not high, generally will not lead to too thick combustible mixture, affect the normal operation of the engine, will not occur oil leakage failure.
But from the carburetor outside and engine on the oil trace analysis, carburetor does exist oil leakage fault, check the connection of the oil hose and carburetor, also did not find aging cracking phenomenon, also did not find the oil trace, excluding the possibility of gasoline from the connection of the oil hose and carburetor leakage.
Check the oil resistance sealing ring of the float chamber shell again. The oil resistance sealing ring is very elastic and does not have any mechanical damage. Also exclude the possibility that the gasoline is leaking from the oil-resistant sealing ring.
Inspection found that the float chamber shell and the line plastic wear caused by the scar, the scar is deep, through the float chamber shell wall, because the leak is very small, it is difficult to be found, the engine works, the gasoline will slowly ooze from the leak, increasing the motorcycle's fuel consumption.
Because of this oil leak failure, the oil and water level will not rise abnormally, the combustible mixture will not be too thick, and it will not affect the normal operation of the engine.
Explained the situation to the owner, the owner although surprised that the plastic can wear through the carburetor, but also confirmed the problem. Start the vehicle with a new carburetor and deliver it to the owner. After tracking, the car's fuel consumption returned to normal.