A frame assembly for a motorized vehicle includes a vehicle body frame with an upper frame, a lower basket frame integrally attached to and extending downwardly from the upper frame, and an auxiliary frame which is separate from and operatively attached to the vehicle body frame. The upper frame includes a head pipe, a tubular main frame section attached to the head pipe, a pair of seat rails extending rearwardly in a divergent fashion from the main frame section, and a rear crossbar interconnecting the seat rails at rear portions thereof. The lower basket frame comprises left and right down tubes extending downwardly in a divergent fashion from the head pipe, a pair of left and right lower pipes extending rearwardly from lower ends of the respective down tubes, and a pair of medial frame sections extending between rear ends of the lower pipes and the seat rails. The auxiliary frame has a width substantially equal to a distance between the left and right lower pipes.