What style grips are you going with?

If they go under the switch housing they will lend support and not require as strong of an adhesive.

If they slip on up to the switch housing but not under on the left side it will require a stroinger adhesive.

I Gorilla glued my left side RSD grip as cheap insurance against it slipping off at an inopportune time......

 

Jap bike shops that deal with dirt bikes will have grip glue, so will KTM dealers. Can also be ordered over internet even tho shipping will likely cost as much as the glue. I've tried some of the other methods with mixed results with rain or washing of bike causing problems. Haven't tried the electrical tape yet.

 

At the suggestion of many on this forum, I used my wife's hair spray. Sprayed bar and inside grip. Worked great. Should be easy to get off when needed.

 

The last few sets of Harley grips I installed required no glue. They are secured by the switch housings, including the left side. I guess after market grip manufacturers haven't caught up yet.