Ok this is how it should be done..Apparently.

Unscrew the Bar-end weight & twist throttle grip to check if its catching, the solution might be to just move the twist grip assembly along a tad.

Dismantle the twist grip assembly, take few pic's as you go along. With the Bar-end removed pull the twist grip housing off & the unattached housing you should be able to slide the twist grip completely off the clip on. Give it a good clean & the inside of the twist grip (usually quite manky inside) Be careful Not to get lubricating spray i.e. WD 40 between the actual Grip & Twist Grip. Put a thin layer of 3 n 1 oil on the clip on bar & reassemble not forgetting to lube the cabes.

Hope that is of help a cut down abstract from SuperBike. 8-)