Before you install your hand grips thoroughly clean the headset bars and you can even sand with very fine sand paper the rough or rust of it. Sand perpendicular to the grips so that grips grab better. You can heat the grips up in some hot (not boiling hot) water to make them more pliable. That was not necessary for me. Use a good and rubber friendly glue and bead it from the half way point back around the whole circumference. This way you will have little to no excess glue as the grip comes to the end. Once it's al the way on check to make sure that the logo is centered in Neutral on the clutch and idle on the throttle. Now working from the midway point to the inside corner work the grip like an accordion so it will stretch out properly . Repeat for the full length of the grip now.
Note: make sure that your throttle grip does not have glue on the inside end, because it needs to spin freely.