I dont think it has gotten any worse ,I put quieter exhaust on so can hear it betterHas it gotten worse lately or always been there? Some level of gear whine is normal. I remember when I bought mine it actually did it worse, but then after some miles on it, it got better. It still whines a little though. I think when you let off the throttle your engine takes up the slack (gear backlash) in the system which creates the noise.
If the bevel gears/bearings are bad, the noise will always be there.
Noise diagnosis over the internet is almost impossible to do with any certainty.
Is the intake stock?I've got a similar noise, but I'm almost certain it's coming from the right airborne, where the throttle body is.
I just bought the bike so I don't know if it's been there a while or not. I hear it it when I let off the throttle, but it stops when I pull in the clutch and coast.
So I'm hoping that it's just air being sucked in and not the bevel gears.