I wouldn't worry about the o-ring on the speedo cable right now. If you do need a new one though the part # is in one of the posts down below the picture in the link I sent.

Anyway, after going back and rereading this thread I have a theory about your clutch problem. I think you damaged the cable when you tipped the bike over, and the damaged cable is not allowing the clutch to engage completely when you let go of the lever on the handelbar after shifting gears. It was as though you were riding with the lever on the handlebar pulled just slightly all the time. The clutch was slipping just a tiny bit all the time you were riding from wherever the tip over was to where you are now. At first it probably wasn't slipping badly enough for you to realize anything was wrong. Until recently.

If you watch the lever on the engine case the the clutch cable is attached to, while pulling the handelbar lever all the way to the grip, the lever on the case should move up about an inch or so as the cable pulls on it. When you release the lever on the handlebar the lever on the case should snap back down to where it started from. Push down on that lever with a finger after you release the lever on the bar and make sure it's down as far as it will go. If the lever on the engine doesn't snap back all the way down then either the clutch cable is not adjusted correctly - has no slack in it - or it is kinked or otherwise damaged, and it is keeping the clutch partially disengaged - allowing it to slip.

Correcting that; either properly adjusting the cable, or, more likely I suspect, replacing it because it  was damaged when you dropped the bike, might fix you problem. Unfortunately it also night not. Riding as far as you did with a slipping clutch might have finally damaged the discs.

I'd start with the cable. Reading through the thread I'm not sure that you've eliminated that as the source of the problem.

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If it is not the cable and the clutch lever is where it needs to be,I'm not sure what to do.  I know I'm having clutch issues but it seems the tests to determine those issues at coming up in the negative. Is Old Feller back in commission?

I tried it a few times before -checking the clutch lever's position. The resistance feels OK in the clutch and the lever always falls within the two marks.
Trust me, I was almost hoping it would be out of range so I had a starting place. I checked several times this morning to be sure before posting.
I've read the clutch argument posts a few times over and am willing to attempt it. My only concern would be having enough or rather, the right tools for the job. I am patient and thorough. I will take my time.
It slipped going into second when I had it started. I know something is going on with the clutch.

Haha. Thanks.
That good luck was a bit ominous. Now I'm worried. JOG, I might give you a ring