I put Avon grips on as well, but I didn't have any issues putting them on. I have removed them several times when I changed out my handlebars. There is a slack adjustment on one of the cables in the left front of the bike. screw it in all the way and you will have lots of slack to put them on. Then unscrew it to lessen the slack.
I love my Avon grips. Very comfortable and way better than OEM.