mysterious flat DS tire.

I got a question for you dark siders out out there. I own a 2013 f6b standard. I am currently running a Falken 195/55R 16 on the rear. Last Friday morning I went out to the garage and noticed that my rear tire was completely flat. I aired up the tire to 35psi and put the bike up on the jack to inspect the tire and found no reason for the flat. Now it is Tues. afternoon and the tire is still holding air. How can this happen? Has anybody had this happen to them? Is it possible the tire wasn't seated on the bead? The tire has approx. 1K miles on it.

Could be one of several things that would let the air leak out and now has resealed enough to stop leaking. I would bet it will leak again. First stop for me after the visual you did would be the valve stem innards. Sometimes even the slightest lube will make the tiny O ring start sealing again if it has got really dry. I'm talking really slightest like rub the outside of your nose then the rubber on the stem.

Check your valve stem. Make sure the valve core is tight. Did you replace the valve stem when you changed the tire? Have you changed out to a metal valve yet. If not, why haven’t you changed out to a 90* metal valve stem. Also is that little black plastic “valve stem retainer” still in place?

Was it locked up where nobody could get to it?
Next, some valves leak if the cap is screwed on too tight.
I had to squirt soap on mine and tighten it to that special place where it wouldn't leak till I got a good one.
I used a cheap Chinese valve.
Some caps have a rubber seal at the bottom. But all it does is push the pin and make it leak.
Make sure there is a hole for the pin to go in at the bottom of the cap.

Valve stem is a good place to start. It's happened a couple times to me with car tires (on cars) through the years.

Yes on the valve stem. It happened to me once. Tire was down a couple of lbs one morning so I aired it up and went to work. Came out after work and it was flat. Luckily it was a Michelin Alpin Run flat. I drove it home 6 miles with zero air pressure. I replaced the valve stem with a metal one and the problem was solved.

I replaced the valve stem and so far problem solved. thank you for all your responses.