Why can't Suzuki Junchi gt 125 run?

The top speed of this car is generally only 90- 100, and the fifth gear is generally a high transmission ratio. Its main function is to save fuel when driving, and the power is not as good as the fourth gear. In other words, your car should be basically normal. If you use it normally in other ways, I suggest you don't try to adjust it, otherwise it will get worse and worse. It is of little practical significance to change the setting parameters of the car just to improve the speed, and it may also cause other changes, such as fuel consumption.