on my 1984 interstate I have rebuilt the carbs, there is open tubes on each carb with no lines to the bottom of the bike. Do those tubes just stop at the carbs or should there be lines to the underside?:sadguy:
The tubes you are referring to are atmosphere vent tubes that allow each carburetor chamber to vent to ambient air. There are no physical connections to these tubes, they need to be open to allow for venting.
You can run it with no hoses connected to the carbs, but I like to put at least short hoses on them, to help keep dirt out of the float bowls. You can get however much you need of this hose at any auto parts store. There have been rare cases of engines cutting out above certain speeds, or when ridden in a crosswind, due to air blowing over the ends of the hoses creating a vacuum in the carbs. I think this is unlikely, but if if should happen, relocating the ends of the hoses out of the airflow will solve the problem.
They probably rotted and fell off a long time ago. Everything made out of rubber was rotted on my '85 when I got it. The only reason I use them is because being longer, it seems it would be harder for dirt to get all the way up the hose, and into the carb. But I live in AZ, where dust is a big deal. On my XT225 dual sport bike I even removed the hose and poured oil through it and put it back on, the idea being that what dirt managed to get into it would stick to the oil on the inside of the hose. But, that is a dirt bike.
They never had vent hoses and there is no external vent to atmosphere. Those tubes are probably not even drilled through into the carbs but are cast there for use in countries where there are no emission controls.