I've also fixed this problem on a brick, in a not so safe way. Don't remember if I push started it, I think I started it in first on the centre stand. If the other ways don't help, try that. Get ready, hold on, push it off the centre stand. Your riding in first gear, pull in the clutch, leave it pulled in, accelerate (hard) back off, accelerate, back off, repeat, all of a sudden you will lose power, then release the clutch, problem solved, ride home, you've got a bargain, try to keep the smile off your face, it won't be easy.