basicaly because your carb still thinks its getting the same amount of air so it gives it the same amount of gas (fyi air/fuel mixture) but since your getting a lot more air at the same amount of fuel it will run lean and can do minimal to great damage to your engine
it should only cost a few dollars to change out your jet to a larger one. stoc is 230, Im guessing you will need abouta 240. you may not even need to change it at all. you have to do a plug shop to tell if it is running rich, lean, or just right.