Abstract: To provide a vehicle body frame structure of a saddle-riding type vehicle that can increase the capacity of an air cleaner and enhance the bending stiffness of the vehicle body frame. The vehicle body frame structure includes a pair of left and right main frames that extend rearwardly from a head pipe, an engine disposed downwardly of the left and right main frames, a fuel tank disposed upwardly of the engine and between the left and right main frames, a pair of left and right engine hangers that extend downwardly from front portions of the left and right main frames and support the engine, and a cross member that connects the left and right engine hangers in a vehicle width direction.

Abstract: To provide a swing arm pivot structure for a motorcycle which can prevent rubbing between a swing arm and a body frame with a simple structure and can reduce a manufacturing cost for the motorcycle. The swing arm pivot structure includes a swing arm for supporting a rear wheel, a pivot shaft mounted to a body frame and inserted through a swing arm pivot of the swing arm, a first bearing located between one end portion of the swing arm pivot and the body frame for pivotably supporting the swing arm, a first collar located between the inner circumference of the first bearing and the pivot shaft, and a second collar located between the first collar and the body frame. The second collar has a rigidity different from the rigidity of the first collar and the body frame.

Abstract: To provide a seat cowl structure of a saddle-riding type vehicle that can reduce weight of a seat cowl support structure, while achieving stiffness to support an occupant load. The seat cowl structure includes a pair of left and right seat rails and a stiffness portion. The pair of left and right seat rails extends rearwardly from a vehicle body frame and is disposed inside a seat cowl. The stiffness portion connects between seat cowl fastening portions of the left and right seat rails in a vehicle width direction and is disposed inside an upper surface portion and side surface portions of the seat cowl.

Abstract: To concentrate mass, to lower the center of gravity, to efficiently and optimally arrange an intake part for making a compact vehicle body. A cylinder inclined to the rear is arranged under a fuel tank and a body of an intake box is housed between a radiator arranged in front of the cylinder and the cylinder. An upper part of the body of the intake box is fixed to a body frame at the bottom of the fuel tank and air taken in is supplied to an intake port through an intake funnel and a throttle body respectively built-in. A lid of an intake duct can be extractably inserted into a window hole provided to the front of the body, a duct part integrated with the lid is arranged over the radiator, and an air intake guide port takes a flow of air in front of the radiator.

Abstract: To provide a seat cowl structure of a saddle-riding type vehicle that can reduce weight of a seat cowl support structure, while achieving stiffness to support an occupant load. The seat cowl structure includes a pair of left and right seat rails and a stiffness portion. The pair of left and right seat rails extends rearwardly from a vehicle body frame and is disposed inside a seat cowl. The stiffness portion connects between seat cowl fastening portions of the left and right seat rails in a vehicle width direction and is disposed inside an upper surface portion and side surface portions of the seat cowl.

Abstract: To provide a swing arm pivot structure for a motorcycle which can prevent rubbing between a swing arm and a body frame with a simple structure and can reduce a manufacturing cost for the motorcycle. The swing arm pivot structure includes a swing arm for supporting a rear wheel, a pivot shaft mounted to a body frame and inserted through a swing arm pivot of the swing arm, a first bearing located between one end portion of the swing arm pivot and the body frame for pivotably supporting the swing arm, a first collar located between the inner circumference of the first bearing and the pivot shaft, and a second collar located between the first collar and the body frame. The second collar has a rigidity different from the rigidity of the first collar and the body frame.

Abstract: To provide a vehicle body frame structure of a saddle-riding type vehicle that can increase the capacity of an air cleaner and enhance the bending stiffness of the vehicle body frame. The vehicle body frame structure includes a pair of left and right main frames that extend rearwardly from a head pipe, an engine disposed downwardly of the left and right main frames, a fuel tank disposed upwardly of the engine and between the left and right main frames, a pair of left and right engine hangers that extend downwardly from front portions of the left and right main frames and support the engine, and a cross member that connects the left and right engine hangers in a vehicle width direction.

Abstract: A mold and a die-cast manufacturing method for the die-cast product, in which a main frame which is contiguously formed with a head pipe constitutes a portion of a hollow light-weight-metal-made vehicle-body frame. The mold includes a core for forming an inner space of the hollow vehicle-body frame. The core includes a core body and a plurality of splints mounted on the core body, the splints having approximately elliptical cross-sectional shapes. The long axes direction of ellipses of the splints are set parallel to a mold split surface of the mold. As a result, measurement of the positional accuracy of the splints is facilitated, a clearance between the splint and the mold can decrease by increasing the dimensional accuracy of splint mounting portions of the mold based on sizes of the splints, and the frame can be manufactured with high dimensional accuracy.

Abstract: To concentrate mass, to lower the center of gravity, to efficiently and optimally arrange an intake part for making a compact vehicle body. A cylinder inclined to the rear is arranged under a fuel tank and a body of an intake box is housed between a radiator arranged in front of the cylinder and the cylinder. An upper part of the body of the intake box is fixed to a body frame at the bottom of the fuel tank and air taken in is supplied to an intake port through an intake funnel and a throttle body respectively built-in. A lid of an intake duct can be extractably inserted into a window hole provided to the front of the body, a duct part integrated with the lid is arranged over the radiator, and an air intake guide port takes a flow of air in front of the radiator.

Abstract: A cowling structure of a motorcycle having a radiator behind a front wheel, including a cowling which covers a periphery of the radiator from a front side of a handlebar, wherein an opening which extends in the longitudinal direction of the motorcycle is formed in the cowling such that the opening traverses an upper portion of the radiator in a side view, thus allowing air to pass through the opening and thus through the motorcycle in the lateral direction thereof.

Abstract: A mold and a die-cast manufacturing method for the die-cast product, in which a main frame which is contiguously formed with a head pipe constitutes a portion of a hollow light-weight-metal-made vehicle-body frame. The mold includes a core for forming an inner space of the hollow vehicle-body frame. The core includes a core body and a plurality of splints mounted on the core body, the splints having approximately elliptical cross-sectional shapes. The long axes direction of ellipses of the splints are set parallel to a mold split surface of the mold. As a result, measurement of the positional accuracy of the splints is facilitated, a clearance between the splint and the mold can decrease by increasing the dimensional accuracy of splint mounting portions of the mold based on sizes of the splints, and the frame can be manufactured with high dimensional accuracy.

Abstract: A cowling structure of a motorcycle having a radiator behind a front wheel, including a cowling which covers a periphery of the radiator from a front side of a handlebar, wherein an opening which extends in the longitudinal direction of the motorcycle is formed in the cowling such that the opening traverses an upper portion of the radiator in a side view, thus allowing air to pass through the opening and thus through the motorcycle in the lateral direction thereof.

Abstract: To improve the maintenance and inspection of a fuel injection valve, as well working of the fuel piping and wiring to the fuel injection valve. An engine fuel injection apparatus includes an air chamber provided on an upstream end of an air intake passage of an engine. A first fuel injection valve for injecting fuel toward the upstream end of the air intake passage is provided on a wall of the air chamber facing a wall connected to the upstream end of the air intake passage. The fuel piping and wiring to the first fuel injection valve is located outside of the air chamber. The air chamber also serves as an air cleaner case provided with a filter element therein.

Abstract: To improve the maintenance and inspection of a fuel injection valve, as well working of the fuel piping and wiring to the fuel injection valve. An engine fuel injection apparatus includes an air chamber provided on an upstream end of an air intake passage of an engine. A first fuel injection valve for injecting fuel toward the upstream end of the air intake passage is provided on a wall of the air chamber facing a wall connected to the upstream end of the air intake passage. The fuel piping and wiring to the first fuel injection valve is located outside of the air chamber. The air chamber also serves as an air cleaner case provided with a filter element therein.

Abstract: To improve the maintenance and inspection of a fuel injection valve, as well working of the fuel piping and wiring to the fuel injection valve. An engine fuel injection apparatus includes an air chamber provided on an upstream end of an air intake passage of an engine. A first fuel injection valve for injecting fuel toward the upstream end of the air intake passage is provided on a wall of the air chamber facing a wall connected to the upstream end of the air intake passage. The fuel piping and wiring to the first fuel injection valve is located outside of the air chamber. The air chamber also serves as an air cleaner case provided with a filter element therein.

Abstract: To reduce the transmission of vibrations from a body frame to a rotary switch, thereby preventing any trouble in the rotary switch and reliably maintaining the function and performance of the rotary switch. A side stand device includes a side stand bracket mounted on the body frame. A side stand is rotatably mounted through a pivot shaft to the bracket, and a rotary switch is provided in coaxial relationship with the pivot bolt through a securing bolt. A sheet is interposed between the rotary switch and the pivot bolt, and a tube and a sheet are interposed between the rotary switch and the securing bolt. The sheets and the tube are formed from rubber members. A cushion member is interposed between an engaging member of an inner rotor in the rotary switch and a locking hole of the side stand. The cushion member is formed from a rubber member.

Abstract: To avoid exertion of an external force on a fuel tank as much as possible. A mounting structure of a fuel tank for a motorcycle provides a fuel tank that is disposed between a pair of left and right frame members of a vehicle body frame and the fuel tank is mounted on the vehicle body frame at a first mounting portion and second, third, and fourth mounting portions. The fuel tank is mounted at each of the mounting portions via a plurality of tubular resilient bodies. The first mounting portion allows resilient support in the fore-and-aft direction and in the vertical direction of the vehicle and limits the lateral movement. The second, third, and fourth mounting portions allow resilient support in the fore-and-aft direction and in the vertical direction of the vehicle.

Abstract: A seat rail extending rearwardly from a vehicle body frame to support a seat. The seat rail is formed of a left-and-right two-split cast product having a substantially flat upper surface and, at the same time, includes cross members. These cross members can be mounted later using bolts. The seat can be arranged above the seat rail and the cross members and, at the same time, a seat engaging member which engages the seat with the cross member can be formed on the cross member. The seat rail is constituted of the left and right seat rails which are divided with respect to a vehicle width center. This seat rail structure provides for simple manufacture and assembly.

Abstract: To enable a reduction of the number of fuel pipes and joint parts to facilitate piping work, maintenance and inspection. An engine fuel injection apparatus includes first fuel injection valves provided on an upstream side of an air intake passage of an engine, second fuel injection valves provided on a downstream side of the air intake passage, and a fuel pump for supplying fuel to the first and the second fuel injection valves. The second fuel injection valves are positioned at a level lower than the first fuel injection valves, and the fuel pump is connected to the second fuel injection valves via the first fuel injection valves by fuel feed pipes, so that fuel does not return to a fuel tank of the engine.

Abstract: To reduce the transmission of vibrations from a body frame to a rotary switch, thereby preventing any trouble in the rotary switch and reliably maintaining the function and performance of the rotary switch. A side stand device includes a side stand bracket mounted on the body frame. A side stand is rotatably mounted through a pivot shaft to the bracket, and a rotary switch is provided in coaxial relationship with the pivot bolt through a securing bolt. A sheet is interposed between the rotary switch and the pivot bolt, and a tube and a sheet are interposed between the rotary switch and the securing bolt. The sheets and the tube are formed from rubber members. A cushion member is interposed between an engaging member of an inner rotor in the rotary switch and a locking hole of the side stand. The cushion member is formed from a rubber member.