a saddle seat having a substantially inverted U-shaped configuration; and

a height adjusting mechanism for the seat having an upper frame mounted beneath the saddle seat, a lower frame adapted to be secured to a bottom surface of the vehicle, a collapsible lever assembly interconnected between the upper and lower frames, a biasing arrangement secured between outermost ends of the lever assembly in the upper frame and the lower frame for urging the upper frame and the seat away from the lower frame, a pair of separate adjustment plates fixed externally to lateral surfaces of the lever assembly and provided with a series of slots defining a number of vertical height adjusting positions, and an actuator extending forwardly of the seat and the upper frame, and pivotally connected to the upper frame, the actuator being directly connected to a pair of links normally biased into engagement with the slots by return springs extending between the links and the upper frame for selectively establishing a desired vertical height adjustment for the seat relative to the lower frame upon pivotal movement of the actuator;

wherein the lever assembly includes a pair of outer levers and a pair of inner levers pivotally connected together at respective mid-portions thereof, each of the levers being comprised of a single, one piece member; and

wherein the biasing arrangement includes a first biasing element having front and rear ends secured in and positioned longitudinally in the upper frame, and a second biasing element having front and rear ends secured in and positioned longitudinally in the lower frame.