I absolutely second what you said Evoled...
As I climb through the RPMs and in lower gears, I feel exactly the same grinding sensation that you have stated... not sure what the fix is, so I try to get OUT of this rpm range QUICKLY! ;-)
I'll add a third on this one. Feels like a grinding/growling sensation felt through the pegs and seat I think (feels like it is coming from the core of the bike if you know what I mean).
I mainly notice it in the higher gears when loafing along anywhere below 4k rpm - so say 50mph in 6th gear.
Does everyone experience this? From videos I have seen many people tend to run the bike in lower gears/higher rpms so may not notice.
I expect it is just a characteristic of the bike, but would like to hear if everyone experiences the same thing to be sure.
Thanks for any replies.