My wife has Kuryakyn ISO Grips on her bike. The left grip came loose because when they were installed they did not clean off the old grip glue before they wraped the bar with tape. The tape glue failed. I got this method of remounting them from a local shop.
First remove all the old glue and make the bar squeaky clean. I used acetone aka as nail polish remover to do this. Nothing else would touch the glue. If you use nail polish remover be sure it is pure acetone. Anything else has additives that will keep the tape from sticking to the bar.
Wrap the bar with high quality electrical tape until the grip is a snug fit. I used 3M Contractors tape.
Mix up enough epoxy to lightly coat the tape with this mixture. They told me to use 60 second epoxy. I used 7 minute because I wanted to be able to get it apart if something did not fit right. It doesn't take as much as you think so spread it lightly.
Push the grip on and position it where you want it and leave it alone until it sets. Be sure you have it where it is supposed to go because once the glue sets its not coming back off without a fight.
Mounting you grips this way makes it easy to cleanup if you ever need to change them again. Getting the glue of is just a matter of cutting through the tape and peeling it off.
Once the glue was set I could not get it to move with both hands. This works great.
Kuryakyn ISO Grips
