[kelly5150]

Yes, I know it all.

First off the Motor one on the head is a breather tube, it was hooked up to the SMOG . You can plug it, keep it open, whatever runs better .

Manifold tube, same issue . The manifold for that bike is not for that Carb.
I would almost bet the Manifold is too small . Take it off and measure the intake of the Carb going into the manifold , and the manifold intake connection at the carb , and see if they are equal. They should be equal, but if not , no biggy . The tube on the intake is for Smog too , plugging it is fine. Ideally you want at least 22mm intake=22mm carb opening into the intake, but the intake could be bigger , not the other way around. I use 22mm as expample, it could both be any MM carb manifold combo .
Understand now ?

And yes all those little Mikunis have both adjustments, you just don't know where they are.

First off is the Idle adjustment, it is that screw above the "Japan" printing in your picture. These carbs idle nearly all the way screwed in looking on that model carb . Back it out and you will discover a Spring, and a needle valve , I promise ! I have the same carb, but in 24mm , I know what I am talking about here.
Air-fuel is underneath the carb, on the Bowl section of the carb , on the side of the carb that sits closest to the intake manifold . You will see what looks like a long vertical solid shaft ? It is right next to it, countersunk into the alluminum with a straightslot screwdriver head in there. It is small, but it is there. You will have a hard time seeing it mounted on the bike, but once you know where it is you can adjust it just fine on the bike. It is countersunk for a reason so it won't get bumped .
Those are nice carbs and that answers all your questions.
Enjoy, Kelly out