Abstract: There is provided a tightening tool control system including a tightening tool and a PC (Personal Computer) for controlling the tightening tool, the tightening tool having a registration mode for detecting a tightening posture when tightening a member and for registering the detected tightening posture in the PC.

Abstract: A motorcycle body frame structure made of an aluminum-based alloy, and suitable for off-road jumping and landing due to its increased rigidity and toughness, and the large stroke of its shock absorber. Maintenance is facilitated because the upper frame member is detachable from the head pipe and from the coupling member connecting the rear portions of the upper and lower frame members. The strength of the engine hanger is enhanced by securing it to a member connecting the front and rear frame portions. A large-size fuel tank is accommodated in a space defined between the upper frame member and left and right lower frame members.