The end caps are a trick because they're on so well they look to be part of the end piece. It's not. I used a small blade to pop it off. Then it's just an allen head screw. Desiree has those grips and they come with two little gear mechanisms. One for the Honda VTX and the other for all other metrics. Use the "other" one.
To get the old grip off without damaging it, spray a little WD-40 (or any silicone lubricant) between the grip and the bar. Then use your compressor and spray air in the same spot. That may be enough. If not, get a long flat head screwdriver and slide it between the grip and bar and just work it around the entire bar. It should be really easy. I did all three methods and had both grips off in about two minutes.
Great choice on grips!