Your bike has to completely warm up for the carb to work properly. If it only does it when the bike is cold or not warmed up all of the way, that is normal.
If it does it after the engine is up to operating temp, then you will have to inspect and clean the accelerator pump area and possibly adjust the accelerator pump rod. The carb slide should start to open a little before the pump rod begins to move. If the pump rod is adjusted to squirt fuel too soon, it will flood the engine and cause a delay in throttle response.