Here is a tip that allows the reduction in throttle movement of our trials bikes with the standard Domino throttle (either fast or slow tubes). This is a big help to novice riders.
This is to limit the stroke of the throttle cable at the throttle tube, by inserting a PVC flange.
This is obtained by cutting a washer in the female part of a 32 diameter PVC fitting (see photo).
The piece must have a width of 7mm to enter the throttle housing. Then, cut out a section of the circle to keep only an arc of between 180 to 250 degrees. It is the length of this arc that determines the stroke of the cable, and ultimately the revs of the bike.
Then simply place this piece at the winding of the cable to create a new stop.
You can prepared several stops with different lengths to adapt to the level of the riders.