Not sure what you're doing with the throttle cable. Do you think it's stretched? sticking?
since it seems to change every time you open the carb I have to ask: are you putting the slide in right (p. 41in the manual). If you put it in backwards it's going off to the races because the slide won't move properly.
Look into the carb with the airbox off, twist the throttle, and let go. You should see that slide move up, then snap back down when you let the throttle go. When you're looking in, you will see a gap at the bottom of the slide.
If you've been playing with that cable, yeah you may have to spend a little time adjusting it now, but see if that slide's in correctly.