A 13-year-old boy who fell off the back of a quad bike was abandoned by the rider, Fife Police said.
Officers say quad bike activities must be supervised
The boy, whose identity has not been released, needed hospital treatment for leg injuries after the accident on Wellesley Road, Methil, on 22 May.
Officers said they have been pursuing positive lines of inquiry in their search for the rider.
Inspector David Latto said the incident typified the attitude of those who flout the rules of the road.
He said: "This is indicative of the mindless attitude of certain individuals who constantly ride quad bikes, mini motos and off road bikes, putting themselves and others at risk of serious injury.
"Police officers will continue their efforts to detect these offences, however, it is time that parents take responsibility to ensure that their children do not use these vehicles unless under properly supervised conditions."
Anyone with information about the incident is urged to contact Fife Police on 01592 251111.