I just bought a ´72 250cc DS7 and I guess two-strokes are just too different for either me or my friends to figure out! I was taking it apart to do some cleanup when I found five tubes running from the carbs and the oil can that seemed to go nowhere. Each carb has two tubes and the oil can has one that runs off the top and back down towards the chain. There isn´t a "bulge" on the end of any of the tubes so it looks like they were never connected to anything. I´m thinking they were for venting, but I want to be sure that´s all they are. If they shouldn´t be connected, is there any particular place on the bike the ends should reside? These tubes look like fish tank air lines. Any info would be immensely appreciated!