Could the fuel filter in your tank. Or some rust in your tank.

 

I had something similar happen to me not so long ago. It was sputtering, I switched it over to reserve, put in new gas, only took a gallon and a half. ran fine afterwards. I chalked it up to bad gas.

 

let us know...

 

At first, I thought maybe you were on Ol' Rt 666, jus' down from the Ol' Indian burial mounds. BUT I see you were on the Super Slab, so throw out the Voodoo/bad spirits theory.

My guess is, you forgot that you did some work or updates on your 'ride bell', and have NOT had it back to the dealer to remapp the bell. This is a PERFECT example, of how gremlins steal rides to the next gas stop. Where, it will lay in ambush, for the next scooter tramp that rolls thru, unsuspecting, that anything is wrong. KEEP those bells properly 'tuned', folks. THIS could have been, YOU !!!!!

Looks like you have enough 'good' suggestions.
I use carb cleaner to check for vacuum leaks.
Chit can the vacuum petcock. MO' Gubment intervention. How in the H*LL did we ever survive with NO kill switch, ONE throttle cable, and a turn on, turn off petcock??? SORRY, IF'N you ain't smart enough to turn your own gas OFF, and then ON, GET RID OF THE "F"ing scoot, I for one, DON'T want you out there on the roadways with me. I mean, CHIT, we are hurtlin' ourselves around at 70+ mph, out in the OPEN, and we are so DAMMD dumm, we NEED the Gubment to step in, and SAVE US from a 'petcock gone BAD/WILD' ????
My 'guess' is, some RUB Dilbert, left the gas turned on, the float leaked, either filled the grudge with 'nasty azzed' gas fumes, or worse, filled the 'open' cylinder with gas, and then he tried to start it. SUE the MoCo., the Dealer, the mechanic, and the latte server. And what diff does it make, with EFI?? NO FLOAT !!!!!!!!!