I don't know what those carbs are but I can tell you they're not original 650 carbs. That small brass nipple on the bottom of the float bowl is the outlet for the overflow pipe inside the bowl. DON'T PLUG IT. If fuel is coming out of it, that means the fuel level in that bowl is rising too high. Either the floats are set wrong, or maybe they're going bad (taking in gas), or your float needle and seat assembly is leaking.