Please ask Yamaha Ling Ying 100 motorcycle not to fill the gas door.

You can't just refuel at low speed. If it's only when the car is cold, it's not a big problem If it's after the car is hot, it's probably the carburetor. It is possible that the carburetor has not been cleaned or debugged. Clean the air filter and carburetor again, and check whether the mixing ratio of the carburetor is improperly adjusted, whether the throttle vacuum film and oil needle are normal, whether the valve clearance is too small, and whether there is a problem with the electronically controlled air door of the carburetor.