You may want to start with new handlebar bushings , they are very affordable I believe there are 4 of them , and make sure you torque them down to the correct torque . I think the bushings are like 6.00 ea. This is where I would start if it were me .
2014 Cross Country
2014 XC , Lloyds A/F , Timing Wheel +4 , PCV , Miller Mufflers , 1/4 Turn Throttle Ring , Dyno Tuned by KMC Powersports 98HP 113 TQ
I have the Ness fly bars also. Although there doesn't seem to be much vibration felt, but the mirrors at 60MPH+ sure vibrate. Cant see much of anything out of them. Curious to see if new bushings will help.
nothing untoward I've noticed since fitting Burleigh Bars, http://www.burleighbars.com.au/
I just bolted them up with new bolts and the old bushings.
I've managed to secure us forum members $100 discount off a set for anyone that desires the very best handlebars that money can buy.
P.S. I will add it was good to get rid of the chrome metal grips that came with my bike, and are in this pic...supremly happy with Burleigh Bars fitted iso-grips instead.
I ran them on a JP and a KP with no issues but as VJ said; try some Vibranators or the Bar Snake. Another easy trick is to take a few rolls of nickels and rap them in a good tape then insert them into the bars until you can't fit anymore in there. You can always fish them out later if it doesn't work for you.