This is a limiter for Domino Single Pull Quick Action motorcyle throttle to prevent the rider from accelerating too much. Ii acts as an endstop.

I needed it to drastically reduce the power of the minibikes that I make available to children who try them for the first time.

With this simple device it is possible to limit the rotation of the throttle knob and therefore reduce the maximum power delivered by the engine without having to modify the carburetion or the control unit: novice riders will never be able to give full power, on the contrary the bike will start to move smoothly and will never reach dangerous speeds.

I drew it in three different lengths (222°, 225° and 230°) to get three different results.
To install it, simply remove the throttle assembly from the handlebar, insert the limiter and reassemble everything.