Where did my oil go?

Ok, this is really weird!
Took a road trip this weekend to visit my son at college...roughly 1K miles in 3 days (actually 500 Friday and 500 Sunday), the bike performed flawlessly. I made sure to change the oil a couple of days prior to my trip...used Valvoline 20w 50 MC oil, same as last change...also changed the filter too...filled the oil just to the point where I had a small bubble in the sight glass...took a couple of 45 - 50 mile rides...made sure to check oil level 20 - 30 mins after both rides. Oil level was spot on.
As I was in the home stretch of my ride, the oil light starts coming on as I'm leaving stop lights...It was kind of weird because all summer long I never lost any oil at all (had three oil changes...one to start the season then another after 2500mi. and then this was the third, maybe 2K mi.) So, anyway, this morning I go out and set my bike up on the center stand...let oil settle...and there is only a tiny bit of oil in the sight glass? WTH? Pull my plugs (to see if they're oily...nope...nice and clean) look around bike??? everything looks just the same as it ever had (little bit of dirt & grime, but no oil leaks anywhere?)?

Where did my oil go? I know it can't just disappear, but if I was burning it, wouldn't it show up on my plugs? And if I had leaked nearly a quart (or more) wouldn't there be quite a bit of leakage somewhere on my bike? And No, there is nothing leaked out on the floor?

WTH?

 

Start the bike and let it warm up for a couple of minutes.

Put it on the centerstand and shut it off; and leave it for 10~15 minutes and check again.

And have a look in the airbox.

 

Rings would be my bet.

 

Here's what I got: 1. Human error i.e. you didn't allow enough time to pass before looking at your sight glass, 20W50 sounds pretty thick to me.
2. Someone may be playing a joke on you by draining off some oil while you're sleeping.
3. You may have a leaking output shaft seal so pull back your swing arm boot, have a pan ready.

 

Rings. My old motor was worse than that on a long run.

 

20W50 is fine and let's don't jump to conclusions.

 

How fast were you going on your trip? Extended distances at high RPM's will consume more oil with a lean running engine. Check the oil again as others have stated after it sits a while. If it's low, fill it back to the full mark and monitor it as you drive it normally. Over the coarse of 38,000 miles on my 750, I have used several different oils and they are not all created equal as far as consumption goes.