(Pics) Problem with Vacuum

Below is a picture of my 1978 KZ650 SR carburettors. Problem: No airbox is on the bike. There are 2 "longer" leads from 2 and 4 that were unplugged sucking free air. The bike at idle when given gas dry heaves and wants to die. Occasionaly when it hits throttle it pins before lowering back down.(Had carbs rebuilt but weren't synched as the bike wasn't running) Looked up alot of stuff about this and seem to wondering if these should be plugged with rubber caps. The throttle issues could be unrelated to this, and more along the mechanics of the carbs.

Note: Running Pods w/o Airbox (carbs rebuilt to factory)

This whole thing is a project for me, and im new to this. I know you guys deal alot with this vacuum stuff so i figured i would give a PIC and detailed problem set.

Dont know much about the 650s but KZ1000s wont run right without either the airbox and filter or a set of pod filters.They depend on "reading" the restriction for proper fuel /air mixture.Also KZ1000s have one of those vacuum lines going to the fuel tank petcock (providing vacuum to open the valve) and one goes to the pollution control valve under the tank and on top of the engine.It recirculates air into the exhaust for cleaner exhaust (ha-ha) engines.If the 650s are the same,most guys here chuck the pollution control system and block off that line.I am sure someone here with a 650 will provide better info re the lines.bj

I believe, and could be wrong, that those are the bowl vent tubes that once attached to the airbox. If so, they can be vented to atmosphere with no ill effects. I think the vacuum line for the pollution gear came from one of the manifolds. That being said, if the carbs are jetted for an airbox, they will not work without it. The mixture will be far too lean for the engine to run properly if at all. The carbs should be bench synch'd before installation and then the fuel level should be checked and adjusted before trying to start the bike for the final fine tuning. If the engine and exhaust are stock, the factory airbox will greatly simplify tuning.

Those are vent lines... don't plug them... they should point down so fuel can drain out if needed.

That middle tee (with no line) is your main fuel inlet and the smaller line near the choke lever is the vacuum line for the petcock.