Your situation is pretty interesting, and I say that because on paper that bike should run way lean and here is why:
1. The main jet at 110 is about right for the setup. With pods it's going to really necessitate jet changes. Main jet, however only dominates 3/4 to WOT and so is not the majority of throttle range you would use.
2. The needle clip has been changed from stock (2) to (if I'm reading correctly, slot 1: "furthest from the tip of the needle). This means that it has actually been made leaner that stock settings. However, you are running rich. IMO the needle should be set to middle position (3rd).
3. IMO and from experience I have had seeing what people do, this needle position was probably a flailing attempt at trying to cure the rich condition. In a way it's kind of the right idea, but it's just wrong and will cause other problems and really screw up your power band.
4. Bike came with other jets, this supports PO was really trying to tune the carbs, unsuccessfully. By the time you got it, it's just random settings trying to compensate for other wrong/random settings.
5. Like I said though, on paper it should be running lean, the fact that you are putting out black smoke (sure it's not blueish? dark black, right?) actually leads me to think that you got other internal problems, top end, compression, leaking oil "pucks", ignition, etc.
6. Also, check to see if your brass carb components are real Kei Hin, not cheap chinese garbage.
7. Write down what your mixture screws are set at.
What I would recommend you do first:
1. Check for vacuum leaks. Do a thorough job, cause if you spray half assed and then call it clean bill of health, you will be moving on from this step and when you are 20 steps later, if it turns out you had a vacuum leak, well that's gonna your fault.
2. You probably have fouled plugs, first thing you should do is replace them. You won't get anywhere diagnosing anything with foul plugs. If they are done you wouldn't even know it cause your plugs are all sooted up. Get new plugs, then run the bike and diagnose. If they foul up again, you know have a baseline of verified data to start at. Take pictures of the old plugs, and then pictures of the new plugs after running them. This will give you what you need: actual data. When you grasp at straws and just change things randomly you end up like the previous owner, frustrated and getting rid of the bike.
2. Test the ignition voltages. This is something easy you can do so try it first.
3. Your carb settings are wrong, so you will need to adjust them eventually. That needle needs to be changed. IMO your settings for PD46C carbs should/good starting point would be:
-110 main jet
-Needle position 3rd position from top (2nd position is stock)
-stock slow jet
-air screws 1.5 out and adjusted accordingly
Finally, pictures, pictures, pictures, pictures, pictures. Post pictures. Clear. Well framed, lighted pictures. You will progress magnitudes faster.
