Yamaha Tianji 125-3 Motorcycle stalled after the idle speed suddenly increased. Please give me some advice.

Check whether the carburetor is blocked, whether the carburetor, valve and intake pipe leak oil, whether the carburetor oil needle and throttle are stuck, whether the mixing ratio and throttle are normal, and whether there are problems with the throttle pipe and throttle handle. If the throttle is suddenly turned off at idle speed, it is normal. In this case, the air intake suddenly increases, while the gasoline intake will lag, which may lead to the sudden dilution and flameout of the mixture. This is also an incorrect driving mode, which is not good for the engine.