Looking at my new to me bike, the choke cable on the carbs seems loose (lot of play where it attaches). When moving the choke lever I cant see anything happening in the carbs. Does the choke move the top plastic looking slides (when looking at the top of carbs)?

 

They are plastic? <Scratching head>

What I recall, is that the end of the choke cable is attached at two points. There is a small clamp that holds the end of the cable sheathing and the very end of the cable attaches to a fairly long metal slide. This does open up chambers inside the top of the carb (thought they were brass) when the choke is opened fully.

 

Yeah, look for something on the middle two carbs. There should be some bracketry that the cable threads into for adjustment and then something it hooks up to that will manipulate the choke on the carbs. I believe this whole operation works horizontally, so externally it appears as though the cable isn't pulling anything up and down, but rather right to left.