This uivention relates to a shock absorber moimting structure on a motor cycle. Particularly tins invention is concerned with the mounting of a single shock absorber on a backbone type frame structure of a motor cycle.
hi the conventional motorcycles twin shock absorbers in the rear is used for absorbing road shocks during driving, These are mounted on two brackets welded to either side of the seat rails of a motorcycle. In such designs the front end of die seat rails are welded to either side of the frame tube which is
extended downwards. Such type of frame structure is called backbone type structure.
Twin shock absorber mountings give higher frictional losses and as a result reduce tractability on road surface. Hence the rider will have uncomfortable ride feel. Tliis is overcome by using a single shock absorber which is disposed at a central position of a vehicle body, hi such known designs the lower end portion of tJie shock absorber is attached to a bracket welded to a cross member joining the left and right swing arm legs, the upper end portion of the shock absorber is supported by an upper bracket which is secured to a cross pipe disposed bridgewise between a pair of right and left seat rails. Such designs are used for racing motorcycles where these compete in most extreme conditions, but this arrangement carmot be adapted to commuting type motorcycles which have backbone type firame structure, hi this type of structure it is not possible to directly mount the singj^ sJi^K absorber on to the rear part of frame since provision of such cross pipe is not feasible due to the limitation of the configuration of the vehicle body frame.

This invention therefore proposes a single or mono shock absorber mounting structure for a motorcycle havmg a backbone frame, which will avoid the disadvantages of the twin shock absorber mounting structure on a backbone type frame as well as the mono shock absorber mounting structure on a commutmg type motorcycle,
A shock absorber mounting structure for a motorcycle comprising a pivot shaft 21 provided at tlie bottom portion of a bottom bracket 27 of a main frame 5; one end of a swing arm 22 connected to the said pivot shaft 21 and the rear wheel of the motorcycle being mounted at other end of the said swing arm for executing a swinging motion; two legs provided for the swing arm 22 having two legs 22L and 22R with a cross member 23; a lower bracket 24 welded on to the said cross member 23 on which the lower portion of a shock absorber 25 is mounted; the upper portion of the said shock abKsorber 25 beuig mounted on to a mounting bracket 26 which is attached to the rear top portion of the said main frame 5; two seat rails 6 attached to die said mounting bracket 26, the said seat rails being also connected to the said bottom bracket 27 of the said main frame 5 by said cross member 28.
This invention will now be described with reference to the accompanying drawings which illustrate, by way of example, and not by way of limitation, one of the possible embodiments of this invention, wherein

Fig. 1 illustrates a general elevation of a motorcycle with a backbone
type frame structure.
Fig. 2 illustrates a view of the shock absorber mounting structure
according to the embodiment
And
Fig. 3 illustrates another view of the shock absorber mounting structure
according to the said embodiment.
A vehicle body frame 4 which supports an air-cooled four cycle engine 3 disposed between a front wheel 1 and a rear wheel 2 is a backbone type frame structure. The vehicle body frame 4 comprises a main frame 5, seat rails 6, lower frame 7, and engine 3 functions as part of the vehicle body frame 4.
The engine unit 3 is accommodated in the space provided by the main frame 5 which extends downwards in the rear part and lower frame 7. A head pipe 8 is attached to the front end of the main frame 5 and a front fork 9 is supported through the head pipe 8 pivotably such that it can be steered by a handle bar 10. A front cowl 11 is mounted in front of the head pipe 8.
As shown in Fig. 1 the vehicle body frame 4 is covered with plural body panels such as side panels 12, rear panels 13 including from cowl 11. The reference nimieral 14 denotes a tank, numeral 15 denotes a seat, 16 denotes piUion hold, 17 denotes main stand, 18 denotes front fender, 19 denotes rear fender and 20 denotes exhaust system.

The rear swmg arm suspension is constructed in such a manner that a pivot shaft 21 is provided at the bottom portion of tlie bottom bracket 27 of the
main frame 5, a swing arm 22 connected to the pivot shaft is mounted at the front end thereof so as to be capable of swinging motion, the rear wheel 2 is mounted at the rear end of the swing arm as a wheel.
The principal portion of the connection between the rear wheel and the vehicle frame is shown in Fi^2 and Fig. 3.
As shown in the Figures, the swing arm 22 has two legs 22L and 22R with a cross member 23. The lower bracket 24 is welded on to the cross member 23 to which the lower portion of shock absorber 25 is mounted. The upper portion of the shock absorber 25 is mounted on to a mounting bracket 26 which is attached to the rear top portion of the main frame 5. Two seat rails 6 are attached to the mounting bracket 26. The two seat rails 6 are also
connected to tlje botton] bracket 27 of the main frame 5 hy cross member 28,
The terms and expressions in this specification are of description and not of limitation having regard to the scope and ambit of this invention.

1. A shock absorber mounting structure for a motorcycle comprising a
pivot shaft provided at tlie bottom portion of a bottom bracket of a
mm frmm; one end of a swing ann connected to tiie said pivot shaft and die rear wheel of the motorcycle being mounted at other end of the said swing arm for executing a swinging motion; two legs provided for the swing arm having two legs and with a cross member; a lower bracket welded on to the said cross member on which the lower portion of a shock absorber is mounted; the upper portion of the said shock absorber being mounted on to a mounting
bracket wlijeh k attached to the rear top portion of die said main frame ; two seat rails attached to the said mounting bracket, the said seat rails being also connected to the said bottom bracket of the said main frame by said cross member.
2. A shock absorber mounting structure for a motorcycle substantially as
herein described and illustrated.