carb 1&4 vacuum lines

carbs 1&4 on my bike have hoses from the vacuum ports, but they do not connect to anything. Its almost like the previous owner assumed the were vents. Where do these attach to? can they just be plugged?

The 1&4 vacuum nipple at the manifold, would go to tee fitting then onto a Air Valve up under the front of your fuel tank. This valve is for adding air into the Exhaust system to help burn unused fuel. If you still have two large hoses at the top of your valve cover than follow those up to this air valve. These two large hoses should connect there and then 1 large hose should run along back to large hole in the front of your airbox. Now if someone has pulled the Air system off, then just cap those nipples. You very well may need to adjust the carbs for the gain in vacuum through those Idle circuits.