Honda Motor Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Eiji Adachi

Tomohiro Fuse

Yuji Noguchi

Kazuhiko Gogo

Mikio Uchiyama

Takanori Okuma

Taichi Honda

Daisuke Soeno

Yuichi Kato

Kazuhito Hayashi

Yasuhiro Nakayama

A rear-wheel suspension system for a two-wheeled vehicle includes a pair of right- and left-side center frames; a swing arm; and a shock absorber, wherein the shock absorber includes a tubular buffer and a spring, wherein the intake system part is a curved tubular member, wherein a position of the spring is shifted downwardly so that the intake system part are moved toward an interior of the vehicle body by a dimension corresponding to the spring, wherein a lower end of the intake system part is above the upper end of the spring, wherein a part of the intake system part is closer than an outer end of the spring to the center of the tubular buffer, and wherein the shock absorber and the intake system part are disposed between a pair of right- and left-side center frames.

Rear-wheel suspension system for two-wheeled vehicle

A rear-wheel suspension system for a two-wheeled vehicle capable of further reducing a vehicle width. An upper end of a coil spring of a shock absorber includes a tubular damper case, a rod connected to a piston disposed within the shock absorber and protrusively provided to be capable of making strokes with respect to the tubular damper case and an external hydraulic sub-tank positioned to be lower than an upper end of the shock absorber. Vehicle body component parts include a connecting tube and the sub-tank disposed to be close to the shock absorber above the coil spring.

Rear-wheel suspension for two-wheeled vehicle

A fender supporting structure of a two-wheeled motor vehicle capable of securing the rigidity of a mounting portion of a front fender and the rigidity of the entire front fender is provided, without enlarging the outer shape of the front fender more than necessary. In a fender supporting structure of a two-wheeled motor vehicle including a fender formed in an arc shape along the shape of a wheel, and a fender supporting member on which the fender is mounted from under the fender supporting member so as to cover an area above the wheel, at least two mounting surfaces at different levels in height are formed on the fender, at least two mounting surfaces at different levels in height are formed on the fender supporting member, and the fender is joined to the fender supporting member with these mounting surfaces.

Fender supporting structure of two-wheeled motor vehicle

To ensure that a down frame in an off-road motorcycle body frame is lightweight, rigid and easy to weld, a down frame extending downward obliquely and backward from a main frame ahead of an engine is divided along its length into a down frame front portion and a down frame rear portion. Welding joins these portions, which abut each other in the longitudinal direction. The down frame front portion is a pipe wrought product formed by extrusion molding and the down frame rear portion is a casting. Since the down frame is welded along a straight welding line extending along its length, welding is easy. Since a main joint and a lower joint are provided integrally with the down frame rear portion as a casting, a separate gusset can be omitted.

Motorcycle body frame structure

To place a muffler in a front area to make it suitable for an off-road motorcycle, A down frame extending downward obliquely from a head pipe ahead of an engine and a lower frame connected with its lower end, extending backward under the engine, are provided. A muffler is located in the vicinity of the joint between the down frame and the lower frame where its rear surface is curved forward in a convex pattern along the down frame and the lower frame. An exhaust pipe extending from a cylinder head is almost S-shaped as seen sideways and its forward curved portion and lower backward curved portion are vertically arranged with its lower end connected with a lower portion of the muffler.

Motorcycle exhaust structure

A frame structure of a motorcycle includes a head pipe gusset forged integrally with a head pipe, and a front fitting recess to which a front wall and front-half parts of right and left side walls of a down pipe are fit is provided with the head pipe gusset. The structure also includes a forged stiffener pipe gusset, and a rear fitting recess to which a rear wall and rear-half parts of right and left side walls of the down pipe can be fit is provided with the stiffener pipe gusset. The right and left front-half parts of the down pipe are inclined in accordance with a draft angle of the front fitting recess, and the right and left rear-half parts are inclined in accordance with a draft angle of the rear fitting recess.

Motorcycle frame structure

A motorcycle frame includes a down tube structured to be light in weight and shaped to simplify radiator piping. The down tube extends diagonally downwards from a head pipe to a front of an engine. The down tube is formed of an angular cross section pipe, with a rib being integrally formed on a front surface inner side, extending vertically. A lower half of a rear surface section of the down tube is made into a tapered section. A space is formed between the tapered section and front sections of a cylinder head and a cylinder head cover of the engine. A water hose of a radiator and an exhaust pipe are arranged in the space.

Motorcycle frame

A frame of a motorcycle is designed to allow for a simplified layout of an intake passageway. The frame includes left and right main frames. Rear ends of the left and right main frames are connected to upper parts of left and right pivot plates. Upper parts of the pivot plates have left and right upwardly extending sections jutting up higher than the rear ends of the main frames. A rear cross member is suspended between the left and right upwardly extending sections. An upper surface of the rear cross member supports a rear section of a fuel tank. A rear shock absorber bracket is provided on the rear cross member for supporting an upper part of a rear shock absorber. A space is defined beneath the rear cross member. An intake passageway, including a carburetor and a connecting tube, as well as an exhaust pipe and the rear shock absorber, are arranged in this space.

To provide a motorcycle frame structure having a head pipe manufactured by forging that enables a significant reduction in forging costs and enables a reduction in welding costs for a front frame and a down tube. A down tube is welded to an upper tongue, a lower surface of a lower flange section and a lower tongue. A weld bead is provided and it is possible to ensure a sufficiently long weld length with regard to the weld bead. Since only the upper and lower tongues are integrally formed with the forged component, there is no need to include an undercut processing in the forging process. Accordingly, it is possible to reduce the manufacturing cost.

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Saitama, Japan

Eiji Adachi