Iv just brought a 80 xs250. And its splutering when u hold it at revs. Dose this sound like bad carby tuning. And can any one tell me how I can tune her up. Iv never had a twin carb bike before. Also iv noticed that the vachum type lines are all blocked off. One on the petrol tank and two on the back side off the engine. Would they all run in to each other. And would the make her not run righy