I just bought a 19mm Dellorto Race model carb. I plan on putting it on my sons Cobra motocross bike, it has the Franco Morini s6 engine with oil injection. I have to keep the oil injection on it for it to be race legal in his class. Which brass fitting on the 19mm is for the oil injection hose. It has a small one on the spout that goes into the intake and it has a small one on the side, I think one of them is a vacuum. Thanks