About half the time shifting from 6th to 5th while decelerating it won't go into gear and just spins loose, like a false neutral or something. I have to downshift again and it will go into 4th. Sometimes but less often it happens from 5th to 4th.
Any ideas? gearbox issues make me cringe.... big $$
How many miles on the bike?
How long since oil was last changed?
Do you blip the throttle a bit to match rpm?
Do you use the clutch?