I have some recent experience with this on some chrome and black ribbed girps similar to the kuryakyn. I took an old sabre saw blade, that was about 1/4" wide by 6" long, and ground the saw teeth off of it on a bench grinder, making a kind of long narrow knife blade. Disconnected the throttle cables, removed the throttle tube from the handle bars, locked the blade in a set of vice gips and worked it around between the gip and the tube, spaying some WD 40 in the gap when possible. Took a while but got the grip off without destroying the tube or the grip. Ain't no way the way these were glued on that an air compressor could have blown them off.
2006 VN900 Classic LT