put a screw or something in the hole,, just for fun take off the side cover for the airbox and see how it can run when it can breath, most of the restriction is the air box,,, 1) airbox, 2) silencer, 3) weld inside the header flange 4) Carb all easy quick mods. remember, an engine is just an air pump that needs to burn the air at a certain temp, it's not a black art