I apologise for not replying to the original thread, but I obviously didn’t see it at the time.
The twist grip is easy enough to replace; you have the main piece which is the handlebar with the slot in it. The parts that you are missing are the tube that fits around the handlebar to form the handgrip (part no. 2) and the steel plug at the end of the handlebar (part no. 15).
The throttle rod passes through the inside of the handlebar tube and through a close-fitting hole in the end plug (this plug is stepped and free to rotate inside the handlebar). There is a tapped hole in the side of this plug so that you can insert a screw to lock the plug and throttle rod together- this hole is positioned so that you can insert the screw through the semi-circular slot in the handlebar and into the plug. The screw will then act as your throttle limit so that you can only turn the throttle rod through a half-turn (180 degrees).
The handgrip tube will fit over this ( you have to remove the screw first ), then line up all of the holes and insert the screw; the screw’s length is critical because it will wind in until it bottoms out on the throttle rod, and you will find that you’ve probably got too much sticking out of the handgrip. Keep taking a little off the end of the screw until it all fits together nicely, then cover the handgrip tube with some car radiator hose. You can cut a hole in the hose to fit over the screw head and it all works well when it’s done!
