I recently purchased my first bike, about 6 weeks ago. So far it has been a great way to get to work and to buzz around town on, Love it!

The problems began maybe about a week ago I first noticed that the bike wasn't responding  well to the choke, in fact turning the choke on even seemed to reduce RPMs. Me being me, easily distracted and crossing all bridges only when the embers of the bridge behind me start burning my heels, it went away, and I ignored it (something I am learning to be not the best strategy). Anyways, yesterday morning I noticed that the issue was back. Only this time it seemed a bit more drastic. I got on the bid and rode to work.

I noticed that the idle was a bit lower, that I was hitting the top end of each gear a bit faster, the ride was a bit rougher, and then it started to stall at lights. By the time I was near the garage at my office, it was sputtering and lurching and I'm lucky to have made it to my parking spot.

I noticed fuel was dripping from to points underneath the carb (just a straight shot beneath where the fuel lines meet the tank, however the tank itself was not leaking). Today, after leaving her overnight at work bc it wouldn't stay running, I returned via train with my tools and my guide and pulled the seat, sides, and a tank off. I believe that the L shaped piece that connects the choke cable to the plunger was not seated properly, however I noticed that with the rank fuel petcock turned off, and after repeating the choke, the bike ran like a charm. Excited (and not realizing that this was only the case when the petcock was off, I Put her back together to ride home only the to be perplexed when the issue occurred again.

Now, I found that with the fuel turned on, even manually engaging the choke by pushing in the plunger with my finger had similar lack of or slight reversal of expected increase in RPMS. I also found that wuth the choke engaged, the leaking nearly seemed to stop. I also noticed that exhaust was very black. Usually I can't even see it.

Any thoughts? Sorry if the info is too vague. I have an appointment for Tuesday at mechanic but would like to figure out for myself if possible

I have been posting and getting good responses on this website all I can tell gu tell you is I pull the carbs and totally rebuild them new diaphragms gaskets the float height should should be okay when they're adjusted at the factory there's really no way they can go out of balance unless a hole gets in the plastic float which is very unlikely

I would suspect that the carbs are overflowing.  Check to see if you can smell fuel in the oil.

Essentially what I'm thinking is the frame petcock is faulty and stuck open, and in addition to this the needle/seat in the carbs are worn and/or the floats are out of adjustment.  In this condition the carb is filling with too much fuel, and the motorcycle (when running) is naturally rich.
Adding the choke to an already rich mixture will definitely lead to black smoke, poor running conditions, fouled plugs, and eventually worse.

The reason it behaves normally with the tank petcock off is because, if the carbs are indeed overfilling, once you stop fuel flow and the fuel level returns to normal the engine will run properly for as much time as it takes to consume all the remaining fuel in the carbs.  But once you allow fuel flow they fill too much once again.

Thanks for the info watcher, I read somewhere that the floats can be over filled if the gas tank is filled too high. I may have slightly over filled the night before this all began. Do you think that this is likely? If so, will simply draining a portion of the tank resolve the problem?

If not, what do you suggest I do, rebuild the frame petcock?

Filling the tank will not cause problems. I'd begin with the carbs. It sounds like a float needle/seat problem to me. Keep us posted on your progress--best wishes.