I suggest you print in PLA because of strength problems. You don't want the thing in the way of your hand, so it must be thin, making the screw a little fragile.
When I drive my moped (Tomos A35 Standard Classic) with speedy exhaust I find it very annoying to manually play with the gas to match my speed with friends. Also, I read that when you don't give full throttle it can save up to 20%. Don't ask why but I thought it was worth the experiment.
The way I use it, is by attaching it to the gas from below so the gas can't be opened fully, this way it works as a limiter. You could also attach it from above and not screw the screw too tightly but this is very risky, because you have to push it back before being able to brake.
For the screw, I used the polyScrewThread_r1.scad from Aubenc: http://www.thingiverse.com/aubenc. You can find his design here: http://www.thingiverse.com/thing:8796.
CruiseControl.scad | 8.9KB | |
CruiseControl.stl | 1.8MB |