How to properly adjust the gs125 motorcycle carburetor mix ratio?

First, basic knowledge


  1. What is a mixing ratio. The mixing ratio is also known as "air-fuel ratio", which is written as "A / F", namely Air / Fuel, the ratio of air to fuel. When mentioning concentration, try to be "strong" or "light", if "high" or "low" refers to the A / F ratio is "air fuel ratio". Therefore, when oil and gas are "thick", more oil and less air, and A / F ratio is "low"; instead, when oil and gas are "light", less oil and more air, A / F ratio is high.


  1. What is the effect of the different mixing ratio on the car? Oil and gas is too thin, the engine is easy to overheat, easy to lead to flameout and even shrink the cylinder situation. Oil and gas is too thick, more fuel consumption, the car is easy to stall after the heat, easy to make the engine carbon accumulation, and the carbon accumulation is too serious is also easy to lead to the engine overheating. So too thin or too thick is not a good thing, especially when too thin is more direct will have a bad effect.


  1. Judging whether the mixing ratio is correct from the color of the spark plug. How do you know if the mix ratio is correct? The easiest way is to judge by the color of the spark plug. Remove the spark plug and see the electrode portion of the spark plug:


Oil and gas are too thin: white (or light brown to white)


Oil and gas are normal: brown


Oil and gas are too thick: black (dark brown to black)


This method can roughly see that the mixing ratio is correct or no according to the combustion condition.


Second, adjust the method


  1. Adjustment method. There are many factors that affect the mixing ratio on the carburetor, but the most well-known one is the mixing ratio screw on the carburetor. This is the simplest way to adjust the mixing ratio, generally speaking to adjust the mixing ratio, also more refers to the mixing ratio screw.


The mixing ratio screw is located on the carburetor, which can be found on the carburetor shell, usually a small shaped flat head screw (usually idle screw by hand), but there may be exceptions, depending on the car type or carburetor form.


How does the mixing ratio screw control the mixing ratio? This should start from the structure of the carburetor, the center of the carburetor is hollow, which is the basic structure of the carburetor, the air will quickly flow through this place, through the oil nozzle, to achieve the function of oil and gas atomization. According to the basic structure of gas intake and the proportion of oil is not easy to adjust, so the general practice on the outside of the place to design a small air pathway, let the air can through the air pathway at the same time, and then make a small valve can control the bypass air pathway intake, achieve the purpose of adjusting the mixing ratio. The mixing ratio screw is located in this air path as a valve. By adjusting the mixing ratio screw in and out, the function of different opening and closing degrees of the valve can be achieved to adjust the intake of bypass air.


So in this structure, when the screw turns "in" clockwise, the bypass air channel becomes narrower, the intake decreases, the oil and gas becomes thicker (A / F decreases); when the mixing screw turns "in" clockwise, the screw turns ", the bypass air channel becomes wider, the intake becomes more, and the oil and gas becomes thinner (A / F increases).


There is another structure that is contrary to the above structure. It is not to bypass "air path", but to design a small bypass "oil road" on the outside of the carburetor, using the amount of bypass to adjust the mixing ratio. The mixing ratio screw is designed on the bypass oil road, and the bypass oil intake amount is controlled by adjusting the mixing ratio screw, thus controlling the mixing ratio. Such a structure to adjust the mixing ratio shade, the adjustment mode of the mixing ratio screw is the opposite: mixing ratio screw "clockwise" clockwise when the screw "into", the bypass oil channel will become narrower, less oil intake, oil and gas thinner (A / F increase); the mixing ratio screw "reverse" clockwise screw "out", the channel of the bypass road will be wider, the oil intake becomes more, oil and gas becomes thicker (A / F decreased). But there seems to be less such design? There are not many types of cars, only the FZ / R150 produced in Taiwan is used in this way, the general car should still be mixed by the above bypass air path than the way of screw control.


The general spread of mixing ratio adjustment: first the mixing ratio screw clockwise gently to the end, and then counterclockwise one and half circle is almost the appropriate mixing ratio position. If you want to adjust more finely, you can first adjust the idle speed to about 1000 revolutions, and then the left and right fine tuning mixing ratio screw, adjustment idle speed will rise or lower, adjust him to an idle speed will be the highest place. Then drop the idle speed back to the speed you think is appropriate, and then turn the mixing ratio screw should be counterclockwise or clockwise adjustment, the speed will drop, which is the best mixing ratio.


You can try the adjustment method mentioned above, because this is the mix ratio adjustment method that most people use.


Or change the color of the spark plug. If the mix beats the screw, turn back to the turn of one and two circles, then clear the spark plug, ride for a while (or start and let it idle for half an hour), and then look at the spark plug color. The color is too white tune more thick, too black tone more light, at least a theoretical basis in the heart feel more practical. But this is really troublesome, after each adjustment, to repeat the "clear spark plug head-ride for a while-to see the spark plug color" steps, to the right position often have to make several times. And the most important drawback of using this method is that the "burning spark plug" can not use too much throttle opening, otherwise the color of the spark plug may not be accurate, so it is quite unpleasant to ride.(This is because in fact, the mixing ratio screw only has a greater impact on the mixing ratio at medium and low throttle opening, and the mixing ratio screw at high opening or high speed is smaller)


  1. Adjust with caution. Relying on the instrument to measure the exhaust, by the measured value to see the oil and gas combustion conditions, and with the throttle reaction to adjust is the right way. But to rely on the instrument to adjust let alone our own car, even most of the car dealers are not possible. So mixed than this thing nothing or don't go to move, unless the car is really bad, or spark plug reaction color obviously wrong, or engine or carburetor modification must be adjusted, or holding the spirit of the car is willing to adjust slowly adjust, or really have a good environment have instruments, technology, otherwise the car condition normal will try not to move it.

How to properly adjust the gs125 motorcycle carburetor mix ratio?

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