Did you check to see if your slide is worn out. With the carb off the bike. Which sounds like it is out most days. Place your fingers on each side of the slide. If you can push it back and forth with a click click click, then it is most likley worn. Might be luck and replace only the slide. But like most on here will tell you, ASK BENDER, your pumper is toast.
Don't think the new tank has anything to do with it.
94 DR 350 SE