duk2n
Site Supporter
Here's something you can try based on some of the stuff I saw with my Concours.
Put the bike on the center stand. Loosen all four engine bolts (just loose, not out) and run the engine. Rev it up a little bit so it's not just idling. Kill the engine and tighten the engine mount bolts to spec in alternating order (don't do all of one then the other, do right lower, left lower, right upper, left upper or similar alternating tightening).
The theory here is that the engine is fastened up to the frame in an unbalanced state. Once you let it run where the engine bolts are loosened, it "settles" into place. You then re-secure it.
No idea if this will work on this bike. Perhaps you need to figure out if the engine needs to be shimmed to get the harmonics right. If the vibrations are really that bad, I can't imagine it'd hurt anything.
Somehow I lucked out since I installed the Givi bars this past weekend and have no vibration/harmonics issues. If it makes a difference, I never had more than one of the four engine mount bolts loose at a time.
Let us know what you find and good luck to you!
I have dismounted the Givi bars and tighten all (not only the 4 that hold the bars) the engine bolts following your suggestion and in the specific order stated by the service manual. I have not ridden the bike yet, will do tomorrow if weather permits it, but I would say it makes not very much difference, the vibration is still there, maybe not so bad, but still there.
I will keep reporting my findings