[Maybe you can descibe your "slipping" problem at high revs again?]
In second, if I rev the engine up too quickly, the drive drops out and the engine revs up, as would happen if you pulled the clutch in.
If I raise the revs moderately, I can get up a bit higher to a given rev, but it will still "drop out" at a certain rev (not sure which rev that is).
I can ride the bike at lower revs, it runs normally.