OSET Electric Trials Bikes

with the bike dialed in to have a low top speed, i find the throttle impossibly sensitive for a 3 year old - for him it is basically a digital on and off switch - providing a near instant 0-5mph acceleration. great torque but intimidating for a 3 year old. I would have hoped that with 2007 electronic technology the throttle reponse would be smooth and linear over the length the throttle turn. Clearly, this isn't so easy to do. Anyone have ideas for a work around?