You probably have a big main jet in the carb with that free flow air filter.
You can drain the fuel bowl, loosen the fore and aft clamps to the carb, work it loose and flip it over to get the fuel bowl off. The main jet should be a 108 and the pilot jet should be 36, you might have a 115 and a 40, and that's where all the fuel goes.
With the stock box, if it runs rich, the jets are too big.
