You definitely have to remove the oil pump cover to disconnect the oil pump cable, but even then it isn't clear how you disconnect that cable. The cable doesn't look like it slides out of the oil pump, it looks like it has to pop out or be pried out, and I can't rotate the oil pump far enough around to make that easily happen.
To me, however, it doesn't appear that disconnecting the oil pump cable will really accomplish anything. I think the white slotted circular piece is stuck inside the black sleeve. I basically need to pull the white slotted circular piece out of the black sleeve but I have been unsuccessful thus far. Perhaps by disconnecting the oil pump cable I will remove all tension on the white slotted circular piece and then it will come out?
I haven't seen any screws inside the black sleeve, but when you look down into the sleeve you can see two metal pieces on top of the white slotted circular piece; these are undoubtedly the ends of the lower throttle cable and oil pump cable, not screws.
Sounds like my last option is to somehow get the oil pump cable off of the oil pump, thereby releasing tension on the last of the cables and hopefully the white slotted circular piece will come out of that black sleeve. THEN I can replace the throttle cable.
Man, I'll NEVER do this job again, I'll just pay someone else to do it. I can change the oil and springs in my KDX forks in the time I've spent doing this!
Thanks for checking your manual about this, I'll get one of those; the Yamaha manual isn't too helpful. If you have any more tips, please share them!