The present invention relates to a "Frame structure of a motorcycle . More particularly this invention relates to frame structure for a motorcycle provided with a pair of rear shock absorber or a mono shock absorber.
In the conventional motorcycle, two independent frame assemblies are used for mounting a pair of rear shock absorber on either side of the frame structure or a single (mono) shock absorber in the center part of the frame structure. Use of separate frame assemblies for such purpose will result in higher inventory, loss of productivity and high cost for development and longer lead-time. Further such conventional types of frames have single . fastening arrangement for fuel tank, which improve to vibration, and rattling over a period of time. In addition, suck frame structure, the front down tube onto which this front part of the engine is mounted is of circular or ellipticaljsection,,which has inadequate stiffness In both vertical and longitudinal direction.
The object of the invention is to provide a single frame structure, which can accommodate either a pair of rear shock absorber or a mono shock absorber.
Another object of the invention is to support the fuel tank firmly onto the frame structure, which acts additionally as a stiffener member faith frame structure

A down tube/of square cross section is connected to the rear bottom portion of the head tube whose other end is left open to receive engine mounting bracket.
I By the above arrangement, the same frame assembly can be adopted for mounting two absorbers or a mono shock absorber.

We Claim:
1. A frame structure of a motorcycle comprising a pair of main tubes welded at the rear portion of the head tube and extending and taking a bend downwards the down portion of the said tubes being welded to an engine mounting bracket structure, while the front end of the said tubes are welded math a cross plate; a mid-portion of the main tubes, before the bend, connected by a pip© whose ends are bent into a U-shape parallel to the main tubes overlapping on both sides, the said mid-portion being welded with a near box-shaped metal structure wherein two holes are provided to mount the top end of a mono shock absorber; the cross plate being provided at the rear at of scat mounting structure tubes and cross mem stud bolts located hole provided in the gusset structure; the gusset and the stud bolts being provided on either side of the frame for mounting; a down tube of square cross section connected to the rear bottom of the head tube whose one end is left open to receive tiled engine mounting bracket