1. Performance and selection of shock absorber oil
　　 Because most shock absorbers absorb impact and vibration energy through the damping force of the oil flow, and convert it into the heat of the oil to dissipate it. Therefore, damping force is closely related to oil viscosity, and oil viscosity changes with temperature. The length of time the motorcycle is used, the ambient temperature during use, etc. are different. Therefore, in order to adapt to various climatic conditions in the area where motorcycles are operated, the following technical requirements are put forward for shock absorber oil:
　　 1. Shock absorber oil should not only have good viscosity-temperature performance and high viscosity index, but also have a low freezing point. When the ambient temperature changes or as the working time increases, the temperature of the shock absorber oil itself changes, the viscosity of the oil should change very little;
　　2. The freezing point of shock absorber oil used in our country shall not be lower than -40℃, that is to say, when the temperature drops to 0℃-40℃ in severe cold winter, the oil should not lose fluidity;
　　3. In all the use ranges of motorcycles (including special conditions such as high speed, full load and overload driving), the shock absorber oil should have as little vaporization loss as possible, which is the so-called low vaporization performance;
　　4. When shock absorber oil is in contact with air, it must have anti-oxidation stability and anti-oil-gas mixing stability, which is the so-called good working stability;
　　5. The shock absorber oil containing impurities will quickly scratch the piston rod or cause the oil seal blade to be incomplete during the motorcyclemono shock absorbers manufacturers driving process, resulting in oil leakage. Therefore, the shock absorber oil must be kept absolutely clean.
　　6. ​​The shock absorber oil must have a good anti-rust and anti-wear effect.

2. Selection and precautions of shock absorber
　　 In summary, the viscosity of the shock absorber oil has a great influence on the performance of the shock absorber. Too viscous oil will make the soft shock absorber hard; too thin oil will make the hard shock absorber soft. In order to change the shock absorption performance of the shock absorber, the brand of shock absorber oil can be changed, but the amount of oil added must not be increased or decreased at will. As my country's motorcycle petroleum products stores and motorcycle specialties and maintenance markets, there is currently no special shock absorber oil for sale, and it can only be solved by self-allocation. Several methods of blending shock absorber oil are now recommended for reference.
　　 1. For motorcycles with low speed and low load (referring to vehicles below 50ml), you can directly purchase L-EOC grade gasoline engine oil with the brand name of 5W/30;
　　2. Use mixed oil to prepare, usually according to the following ratio:
　　A. Use 22# turbine oil and transformer oil to mix 50% each;
　　B. Mix 40% 22# turbine oil and 60% transformer oil;
　　C. Use 60% 22# turbine oil and 40% transformer oil to mix and deploy.
　　 It is worth pointing out that after the national standard "GB2357 Steam Turbine Oil" was formulated, the trade name of turbine oil was replaced by steam turbine oil. As the steam turbine oil has a variety of different performance, according to the current appearance of several steam turbine oils, the viscosity grade is 32 grades of L-TSA turbine oil (this oil is similar to the original "GB2537 steam turbine oil" No. 30, " SYB1656 Turbine Oil "No. 22) instead of the original No. 22 turbine oil is most suitable.
3. When changing the shock absorber gasoline, you can remove the steering handle, front wheel, front fender, and brake caliper in order, loosen the fixing screw of the upper link plate, the fixing screw of the steering column, and turn the handle tube back and forth. Slowly pull out the handle tube etc. For motorcycles equipped with a front fork dust shield, the dust shield and front fork cover bolts should be removed first (the front fork cover bolts may pop out under the action of the spring, so be careful). If it is an air pressurized type, before loosening the bolt, press the valve core to exhaust air. Remove the spring washer, spring guide tube, and front fork spring in order, move the handle tube, and pour out the shock absorber oil in the front fork (as shown in Figure 3). Then, inject the recommended front fork shock absorber oil according to the specified amount of oil, and then slowly pull the handle tube two or three times to remove the mixed air, and finally install it in order. Now briefly introduce the oil volume of the front fork shock absorber of some motorcycles (refers to a single one).