For safety purposes.
Im sure the EU CE folk will now make 1000 laws about this if the see this post.
I cut my full length hand throttle into a quarter hand length throttle, and butted it with the end off another hand grip.
If the throttle pulls off in your hand, being previously damaged by numerous means, while in use, the motor can get stuck at full speed compounded by the fact you can lose one hand on the handle bars for controlling the bike. This can be a very dangerous situation. Some people, like my self, can ride at times single handed on their bikes.
Im not sure how the new full hand throttles compare to the old gm full throttle. My full hand throttle pulled off just lifting the bike up as it lay on the ground by using the full throttle.
All that needs to happen is the bike falls and or receives a nasty impact, and this puts shock onto the full twist grip, causing damage to the plastic tabs that holds the grip into the throttle chassis, and the twist grip can pull off in your hand anytime after this..
After the above mod was applied to a broken throttle that the twist grip was broken to the point it didnt even stay onto its fixture, always sliding off , and that broken throttle still lasted for years with this mod.
I cut every full throttle I buy now and mod it to a quarter hand length throttle, default mod I say.
Leave 3.5 CM on the twist grip after the cut, maybe more to make sure there is room for error so you can work the edge is square and smooth, and make some slippy washers from some hard plastic to go between the butt and twist grip, smooth the twist grip edge where it is cut, set it up so the butt cant pushed too hard against the twist grip, and it works the charm.
This is the throttle mod I speak of explained in MSpaint.