Alright, I am going to admit upfront that I think I screwed up. I am looking for some advice on what might be wrong with my bike. Here are the facts that I think relate to the case:
My bike has 12,900 miles on it. It is a 2008 Roadliner. I have done all of the service and mods myself. I am not very mechanically experienced, but I want to know my bike better than just “I put gas in it and it goes vroom”
The problem I am having is that the clutch is slipping. At least I think that is the problem. It started about 1,500 miles ago. I would be cruising along in 3rd, 4th or 5th and when I accelerate the motor revs up but the bike doesn’t speed up right away, it lags. I will be cruising at say, 2k rpm and I will gun it and the motor will rev to 4-5k without increasing speed at all. Then it is like the “transmission catches up with the engine” so to speak. The lower the gear the shorter the lag time.
I don’t do burn outs, or pop my clutch or mistreat my bike, just to be clear.
Here is the screw up part. I am wondering if it might be due to an oil change mistake. Here is my maintenance log:
600 miles oil and filter 20w50 Castrol 4T 20w50

685 transfer case oil
6,120 oil 20w50 Castrol 4T 20w50 on this one I noted that it only took 3 quarts, which I found very strange. Later I realized that I had forgotten about the third plug back by the shock.

8,795 oil and filter 10w40 ATV oil Vavoline ATV 10w40 (this was SG, MA oil)

11,726 oil 20w50 Spectro Golden semi synthetic

All are JASO MA NOT energy conserving oil

So, my change intervals weren’t spot on, but shouldn’t have been far enough apart to cause that kind of damage.
The change where I missed a plug and shorted it on fresh oil went less than 2,600 miles before I changed it again
The 10w40 isn’t the right weight but it was the proper class of oil. And it was in there for less than 3,000 miles when the slipping started.
The most recent oil change didn’t seem to help at all.

So, is it really clutch slippage?

Did any of my blunders cause it?
What other info is needed to figure this out?