Air Joint Pipe on Carb

[Vintage Biker]

Purchased an 84 NH700 a couple months ago and started rebuilding the carbs. Between carbs #1 and #2 and carbs #3 and #4 is a plastic "T" mounted up high on the carbs. The service manual describes the part as "air joint pipe".  I'm sure they are part of the emissions recirculation system, and the manual shows a hose attached to the "T" and going to a box with other hoses. 
My question - my "T's" have no hose and are completely exposed to the atmosphere.
1) do I seal the open end -
2) attach a piece of hose and run it to the box referenced in the manual.
3) attach a piece of hose and attach a "micro filter" to the end.
The bike seemed to run well with the end open but im sure the carbs were exposed to unfiltered air.

Thank you for your assistance

[mollusc]

Those are just breather pipes.  On non-California bikes they're open to the atmosphere.  There's usually a hose on them that hangs down so that water doesn't get in there.
They're only connected to the evap system on California bikes, which have a whole lot of other parts as well.

[Bob H]

...My question - my "T's" have no hose and are completely exposed to the atmosphere.
...but im sure the carbs were exposed to unfiltered air.

The breather pipes Mollusc referred to are simply to allow air to replace the gas in the float bowls as you ride. Otherwise fuel could not enter the float bowls, if they didn't "open" to the outside world.

That air does not need to be filtered, and it's nothing like an air intake into the combustion chamber.

I'm sure they are part of the emissions recirculation system, and the manual shows a hose attached to the "T" and going to a box with other hoses.

Do you have a California bike?  The manuals will show the obligatory California data, even though a small percentage actually have the California garbage (mine did - I am from the land of Fruits and Nuts)
For more info, check out this thread
https://nighthawkforums.com/index.php?topic=214.msg1642#msg1642

[Vintage Biker]

Thanks Gents. The information was very helpful. Not a California bike. I'll add some hose and let it hang down to keep the water out. Larry