You can use thick CA on them (also known as Crazy Glue). The thick CA does not bond instantly and allows you time to slide the left grip into place. The right (throttle) grip is held in place by the cable guides.
Gorilla Glue for me too. Gives you time to work the grips around and holds great. You can also still remove the grips later on as the glue doesn't eat into the grip.
If the grips have a design, put the throttle side on first so you can match the clutch side to it. I put my ISO grips on then noticed the rotation of the left didn't match the right and had to take it back off. I'm picky.
You don't need glue !! Just wrap the left bar with duct tape and push the new grip on. You should have to push hard. Once it's on it won't twist like it did when I used the iso glue. Also you can remove it if you have to. Tony.