Why doesn't the new oiler of Yamaha motorcycle catch fire?

After replacing the carburetor, it won't catch fire. Check whether the carburetor is installed and debugged correctly, whether there is oil intake in the carburetor, whether there is leakage in the intake pipe, and whether the throttle valve and throttle pipe are improperly installed and stuck. If it is a scooter or a canopy, Yamaha uses a negative pressure fuel tank switch, and after changing the carburetor, it is impossible to start it directly after re-sucking oil or playing for a while. In addition, the new carburetor may sometimes have problems, which can be cleaned and re-debugged.