When the motorcycle is hot, it runs normally in neutral and idling, but as long as it runs at a speed of more than 30 yards with gear, release the throttle.

When the throttle is closed during driving, check whether the mixture is too rich. You can dilute the mixture a little and see if the air filter is blocked. When the throttle is turned back during driving, the throttle suddenly closes and the intake air decreases rapidly. Because gasoline is heavier than air, it may continue to enter the engine under the action of inertia, making the mixture too rich and turn off. It is also possible that the carburetor has poor high-low speed transition performance, so you can try a suitable carburetor if you have the conditions. In this case, it is generally not easy to turn off the fire if the throttle is turned off immediately and then the throttle is allowed to slide at idle speed.

If the vibration is large, check whether the fixing screw between the engine and the frame is loose and whether the pedal lever screw is loose.