I also considered a piece of brake line in between the throttle slide and the top that screws on top the carb to limit the slide pull.
Here is my near death experience with a spree today:
I re-wired the machine for kick-start only, and just the basics. No lights, blinkers etc. Got rid of the entire wire harness and all new wiring for just the basics.
stator is wired directly to cdi, voltage regulator is only used for the electric choke, 1 wire running up handle bar for kill switch....
I decide to fire the machine before making all connections permanent. Give it three kicks and it wont start
At this point the throttle cable is not attached to the twist grip, just a cable hanging there. So I grab the handle bar with one hand,
pull on the throttle cable with the other hand and give it a kick. The machine starts, and I am stuck to it, 70vdc running thru my body.
I can barely hear anything but realize this is really bad, i try to let go but cant, no muscle movement. After a few seconds my muscles
loose grip and i fall too the ground glad to be alive. 4 hrs later I am still shaken up by it

, call me a whimp but I will NEVER forget to hook up and engine ground again
Because I didnt hook up the main green wire from the starter to the frame (frame is where my cdi gets ground from) I was the ground connection
From the frame to the engine. The cdi box was pulling its voltage thru me the spark the coil. throttle cable being in my hand is the engine ground, hand on handle bar frame ground