Harsh Vibration @ 5500-6000 Revs

[Seamaster]

As it says above harsh vibrations @ 5500 revs and above whether the bike is under load or not, stationary or moving, coming through the engine to the foot pegs and rendering the mirrors useless.
Throttle bodies have been adjusted using a carbotune.
Been like this for some time but it is the last issue to finally get the bike right.
The bike is an 850GS, 16500miles, reg 1999
Thanks and any suggestions

 

[jonesai]

Ive got the same problem with my 1999 1150GS. Perfect balance on the manometer tube at 5000 rpm under load but vibes badly on the LH foorest and from under the seat.I have given up and accepted it as due to the inherent problems with a parallel twin giving poor dynamic balance.The latest 1200Rt has a balancer shaft fitted but still vibes a bit after 5000 rpm I understand from reviews

 

[Colban]

Are you sure the carbtune gizmo is working correctly?.
You could try balancing the TBs and then swopping the pipes between the TBs and see if the reading stays the same.
Alternatively,try it using a Manometer.
It wont be perfect as there are large lumps of metal in there thrashing around.