Cut along the length of the non-throttle grip with a razor knife. When you cut through the grip and see the metal of the handlebars, pull on one side of the cut to remove the grip.
Cut down the back of the throttle side grip with a razor knife. When you cut down to the throttle tube, lift one side of the cut grip. Continue slowly cutting along the throttle tube. Cutting too deep will damage the throttle tube. Pull the grip off the throttle tube as described for the non-throttle side grip.
Clean the area exposed when removing the old dirt bike grips. Spray aerosol contact cleaner on a clean rag and thoroughly wipe both the throttle tube and the non-throttle side of the handlebars.
Cover the open end of the throttle tube with duct tape. If the throttle tube of your dirt bike uses a closed end throttle tube, skip this step.
Apply grip glue to the end of the throttle tube and the inside edge of the new grip opening.
Slide the grip onto the throttle tube. Quickly position the grip as the glue will set quickly.
Apply grip glue to the non-throttle side of the handlebars and the inside edge of the second grip. Slide and immediately position the grip.
Make two wraps around the end of each installed grip with tie wire.
Cut the tie wire to length with the wire cutting jaws of a pair of safety wire pliers. Twist the two ends of the wire together with the jaws of the pliers. Tuck the twist to extend 1/4 inch below the bottom of the installed grip. Tuck the twist under the wrap to avoid a glove catch hazard. Repeat the process on the second installed grip.