Hey. I'm a mechanic so I know engines. Problem with yours is the same as you trying to breath through a straw. All you need to do is change your air filter to one that will let it suck air easier. K&N have a great range and definitely one to fit your bike. The other is exhaust fumes. You gotta clear all old engine breath so it can continue exhaling easy. That means a new. Exhaust pipe called an expansion chamber. Once you do them, you'll see a difference. If you wanna go further, try polishing all the ports. That's the seat where the valves sit. Polish them up smooth, also any lips and edges that protrude at the mouth of the carb. It aids airflow down the throat of the carb.
Airflow flows faster over flat surfaces then ridged surfaces.