What exactly is this bit on my carb, and should I be concerned that the top bit with the mitsubishi logo can spin a bit?

On a semi-related note, in the following picture :


where does the other end of part number 51 go?? 

The other part of 51 plugs into the airbox, it's just an air vent hose. If you don't have your airbox anymore it should just be hanging out somewhere.

Where exactly is that little piece in the first picture attached? I've messed with my carbs plenty and it doesn't really look familiar to me.

It would be part 49 in the pic. Apparently it's a valve of some sort, but I have no idea what it does, or what effect rotating the top part will have.

I"m gonna assume these are the newer version carbs? I don't think my bike has one of those.

Part #49 looks to be a vacuum switching valve (VSV).  I imagine it has some emissions related purpose.

-Jessie

It's the power converter switch for the dilithium charge as it enters the flux capacitor. Earth ending catastrophes will ensue if you open it or drop it. Be very careful, ALL of our existences are now resting in your hands...

Michael

it would appear from further examination/research, to be some kind of Vacuum electrical switch. But buggered if I will trace the wiring to see what it connects to, and I still have no idea what the twisty top bit affects