EP2650528A1

EP2650528A1 - Motorcycle

Info

Publication number: EP2650528A1
Application number: EP13162676.4A
Authority: EP
Inventors: Katsuya Yazaki; Sadao Nogi
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2012-04-11
Filing date: 2013-04-08
Publication date: 2013-10-16
Anticipated expiration: 2033-04-08
Also published as: BR102013005325B1; CN103373425A; PH12013000070B1; MY166090A; PH12013000070A1; BR102013005325A2; EP2650528B1; JP2013217338A; ES2525201T3

Abstract

When a motorcycle 1 is viewed laterally, a concave region 12 is formed rearward of a head pipe 3, forward of a seat 9 and above a main frame 4. A throttle body 44 is provided at its lower end portion with a lower connection opening 44a connected to a first intake pipe 42, and is provided at its upper end portion with an upper connection opening 44b connected to a second intake pipe 46. When viewed from above the motorcycle 1, the upper connection opening 44b, the lower connection opening 44a and an intake port 25 at least partially overlap with each other. An injector 50 is attached to a front portion of the throttle body 44.

Description

The present invention relates to motorcycles.
"Underbone type" motorcycles have conventionally been known. An underbone type motorcycle includes a body frame having: a head pipe for rotatably supporting a handlebar; and a main frame extending obliquely downward and rearward from the head pipe. An engine is located below the body frame. In the underbone type motorcycle, a region of the main frame, located between the handlebar and a seat, is reduced in height. Therefore, a rider can easily straddle the main frame when getting on the motorcycle, and thus can easily get on and off the motorcycle.
JP-A-2000-249028 discloses an underbone type motorcycle. An engine of the motorcycle includes: a cylinder block extending forward from a crankcase; and a cylinder head fixed to the cylinder block. At an upper portion of the cylinder head, there is formed an intake port through which air is introduced into a combustion chamber. The intake port is connected with one end of an intake pipe, and the other end of the intake pipe is connected with one end of a throttle body. The intake pipe extends upward from the intake port, and then significantly bends forward. An injector for injecting fuel is attached to an upper portion of the intake pipe. The other end of the throttle body is connected with another intake pipe connected to an air cleaner.
In the motorcycle disclosed in JP-A-2000-249028 , the intake pipe provided with the injector is significantly bent. Therefore, it is hard for air to flow smoothly through the intake pipe, making it disadvantageously difficult to introduce a sufficient amount of air toward the intake port. This might result in a reduction in intake efficiency and a decrease in engine output. It is also hard to direct an orientation of the injector toward the combustion chamber. Therefore, there is a limit to fuel efficiency improvement. In the underbone type motorcycle in particular, the main frame is located at a low position, thus reducing the degree of freedom for installation positions of the injector and the throttle body. Hence, it is difficult to enhance engine output or improve fuel efficiency while allowing a rider to get on and off the motorcycle easily.
The present invention has been made in view of the above conventional problems, and its main object is to provide a motorcycle capable of enhancing engine output or improving fuel efficiency while allowing a rider to get on and off the motorcycle easily.
The main object of the present invention is achieved by a motorcycle according to claim 1.
A motorcycle according to the present invention includes: a body frame having a head pipe, and a main frame extending obliquely downward and rearward from the head pipe; a seat supported by the body frame and located rearward of the head pipe; an engine having a cylinder unit located below the main frame, the engine being supported by the main frame so as not to be swingable; an air cleaner at least partially located below the main frame and higher than the cylinder unit; and an intake passage connected to the cylinder unit and the air cleaner. When the motorcycle is viewed laterally, a concave region is formed rearward of the head pipe, forward of the seat and above the main frame. Inside the cylinder unit, there are formed a combustion chamber and an intake port at least partially located more forward than the combustion chamber. The intake passage has: a first intake pipe connected to the intake port; a throttle body connected to the first intake pipe and incorporating a throttle valve; and a second intake pipe connected to the throttle body and the air cleaner. The throttle body is provided at its lower end portion with a lower connection opening connected to the first intake pipe, and is provided at its upper end portion with an upper connection opening connected to the second intake pipe. The upper connection opening, the lower connection opening, and the intake port are located so as to be at least partially overlapped with each other when viewed from above the motorcycle. The motorcycle further includes an injector for injecting fuel toward the intake port, the injector being attached to the throttle body or the first intake pipe so as to be at least partially located more forward than the throttle body.
In the motorcycle, the concave region is formed rearward of the head pipe, forward of the seat and above the main frame when the motorcycle is viewed laterally. Therefore, a rider can easily straddle the main frame when getting on the motorcycle, and thus can easily get on and off the motorcycle. Moreover, the upper connection opening of the throttle body, the lower connection opening thereof, and the intake port are located so as to be at least partially overlapped with each other when viewed from above the motorcycle. Furthermore, the injector is at least partially located more forward than the throttle body, and the injector injects fuel toward the intake port. Therefore, an injection direction of the injector can be further directed toward the combustion chamber. Accordingly, the motorcycle is capable of improving fuel efficiency while allowing a rider to get on and off the motorcycle easily.
For example, if the entire injector is located more rearward than the throttle body, the first intake pipe has to be significantly bent forward in order to ensure an installation space for the injector. However, in the motorcycle, the injector is at least partially located more forward than the throttle body. Therefore, the first intake pipe does not have to be significantly bent forward. Accordingly, the degree of bending of the first intake pipe can be reduced, thus allowing air to flow more smoothly through the first intake pipe. As a result, an improvement in intake efficiency is enabled.
In one preferred aspect, the throttle body preferably includes an upper edge and a lower edge. The throttle body is preferably inclined rearward so that a front end of the lower edge is located more forward than a front end of the upper edge, and a rear end of the lower edge is located more forward than a rear end of the upper edge.
Such a structure can reduce a vertical length of the throttle body. Since utilization of a space located forward of the throttle body is facilitated, the injector can be compactly located in this space. Therefore, the concave region can be maintained at a low position, thus allowing a rider to get on and off the motorcycle with sufficient ease.
In another preferred aspect, the injector preferably includes an upper edge and a lower edge. The injector is preferably inclined forward so that a front end of the lower edge is located more rearward than a front end of the upper edge, and a rear end of the lower edge is located more rearward than a rear end of the upper edge.
Such a structure allows the injection direction of the injector to be further directed toward the combustion chamber. Hence, fuel efficiency is further improved. Since the injector can be reduced in vertical length, the concave region can be maintained at a low position, thus allowing a rider to get on and off the motorcycle with sufficient ease.
In still another preferred aspect, between the intake port and the combustion chamber, there is preferably formed an opening opened and closed by an intake valve, and the injector is preferably located so that an extension of an axis of the injector intersects the opening.
Such a structure allows the injection direction of the injector to be further directed toward the combustion chamber. Hence, fuel efficiency is further improved.
In yet another preferred aspect, when the motorcycle is viewed laterally, a lower end face of the first intake pipe is preferably located below a border line of an upper wall of the cylinder unit.
Such a structure allows the first intake pipe and the throttle body to be located at lower positions. Therefore, an installation space for the injector can be sufficiently ensured below the main frame. As a result, the throttle body and the injector can be compactly located, while a rider is allowed to easily get on and off the motorcycle.
In still yet another preferred aspect, the throttle body preferably has a length equal to or less than 1.5 times that of the injector.
Such a structure allows the throttle body to be easily located in a small space between the main frame and the cylinder unit.
In another preferred aspect, the first intake pipe preferably has a length shorter than that of the throttle body.
In such a structure, the length of the first intake pipe is short, thus allowing the injector to be located close to the combustion chamber. Therefore, the injector can be more favorably directed toward the combustion chamber, resulting in a further improvement in fuel efficiency.
In still another preferred aspect, in the air cleaner, there is preferably formed a connection opening located rightward or leftward of the main frame. When viewed from behind the motorcycle, the second intake pipe is preferably extended upward from the throttle body so as to be inclined rightward or leftward toward the connection opening and connected thereto.
Such a structure can increase a length of the second intake pipe compared with a case where the second intake pipe extends straightly forward as it extends upward. Therefore, even when the first intake pipe is short, an overall length of the intake passage can be sufficiently ensured. Accordingly, intake characteristics of the engine can be favorably maintained.
In yet another preferred aspect, the connection opening is preferably formed at a rear portion of the air cleaner.
Such a structure can reduce a region of the second intake pipe located outside of the air cleaner. Therefore, a space located between the main frame and the cylinder unit and occupied by the second intake pipe can be reduced, and the installation space for the injector can be sufficiently ensured.
In still yet another preferred aspect, the second intake pipe is preferably bent by 90° or more inside the air cleaner.
Such a structure can further increase the length of the second intake pipe without increasing the space occupied by the region of the second intake pipe located outside the air cleaner. Thus, the overall length of the intake passage can be sufficiently ensured.
In another preferred aspect, inside the air cleaner, the second intake pipe preferably extends from a position leftward of the main frame to a position rightward of the main frame, or extends from a position rightward of the main frame to a position leftward of the main frame.
Such a structure can further increase the length of the second intake pipe without increasing the space occupied by the region of the second intake pipe located outside the air cleaner. Thus, the overall length of the intake passage can be sufficiently ensured.
In still another preferred aspect, the second intake pipe is preferably located so as to be overlapped with the main frame when the motorcycle is viewed laterally.
Such a structure can increase the length of the second intake pipe, and thus the overall length of the intake passage can be sufficiently ensured.
In yet another preferred aspect, at an outer wall of the second intake pipe, there is preferably formed a concave portion facing the main frame.
Such a structure can increase the degree of bending of the second intake pipe while avoiding interference between the second intake pipe and the main frame. Hence, intake efficiency is further improved.
In still yet another preferred aspect, a rear end of the air cleaner is preferably located more rearward than a front extremity of the throttle body, and more forward than a rear extremity of the throttle body.
Such a structure can shorten an overall fore-and-aft length of the air cleaner and the throttle body. Hence, the air cleaner and the intake passage can be compactly located while a volume of the air cleaner is ensured.
In another preferred aspect, the injector is preferably located below the air cleaner.
Such a structure allows a space, located below the air cleaner and forward of the throttle body, to be effectively utilized as the installation space for the injector. Thus, the injector can be compactly located.

FIG. 1 is a side view of a motorcycle according to Embodiment 1 of the present invention.
FIG. 2 is a side view illustrating components of the motorcycle according to Embodiment 1 of the present invention, such as part of an engine and an air cleaner.
FIG. 3 is a left side cross-sectional view of a throttle body according to Embodiment 1 of the present invention, and its surroundings.
FIG. 4 is a top plan view of the throttle body according to Embodiment 1 of the present invention, and its surroundings.
FIG. 5A is a right side view of part of the engine according to Embodiment 1 of the present invention, and its surroundings.
FIG. 5B is an enlarged view of the main parts of FIG. 5A.
FIG. 6A is a left side view of part of the engine according to Embodiment 1 of the present invention, and its surroundings.
FIG. 6B is an enlarged view of the main parts of FIG. 6A.
FIG. 7 is a rear view of the air cleaner according to Embodiment 1 of the present invention, and its surroundings.
FIG. 8 is a rear view of the air cleaner according to Embodiment 1 of the present invention and its surroundings, from which a main frame is removed.
FIG. 9 is a left side view of the air cleaner according to Embodiment 1 of the present invention, and its surroundings.
FIG. 10 is a top cross-sectional view of the air cleaner according to Embodiment 1 of the present invention, and its surroundings.
FIG. 11 is a rear perspective view of a second intake pipe according to Embodiment 1 of the present invention, and its surroundings.
FIG. 12 is an enlarged view of the main parts of FIG. 11.
FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 12.
FIG. 14 is a perspective view of the motorcycle according to Embodiment 1 of the present invention.
FIG. 15 is an enlarged view of a region XV of FIG. 14.
FIG. 16 is a left side cross-sectional view of an intake passage according to Embodiment 2 of the present invention, and its surroundings.

Hereinafter, one embodiment of the present invention will be described. In the following description, "front", "rear", "right", "left", "up" and "down" mean front, rear, right, left, up and down with respect to an occupant of a motorcycle 1, respectively. Reference signs "F" , "Re", "R" and "L" used in the drawings represent front, rear, right and left, respectively.
As illustrated in FIG. 1, the motorcycle according to the present embodiment is the "underbone type" motorcycle 1. The motorcycle 1 includes a body frame 2 made up of a plurality of frame members. The body frame 2 includes a head pipe 3, a main frame 4 and a seat frame 5. In the underbone type motorcycle 1, a concave region 12 is formed rearward of the head pipe 3, forward of a seat 9 and above the main frame 4 when the motorcycle 1 is viewed laterally. A region of the main frame 4, located between the seat 9 and the head pipe 3, is reduced in height. This allows a rider to straddle the main frame 4 easily. In other words, a rider is allowed to straddle a body of the motorcycle 1 easily.
A handlebar 7 is rotatably attached above the head pipe 3. A front fork 6 is supported below the head pipe 3. An axle 8a is fixed to lower end portions of the front fork 6. A front wheel 8 is rotatably attached to the axle 8a. A fender 10 is provided above and rearward of the front wheel 8.
As illustrated in FIG. 2, the main frame 4 extends obliquely downward and rearward from the head pipe 3 in side view. An engine 20 is located below the main frame 4. An air cleaner 30 is located above the engine 20. The air cleaner 30 is connected to a cylinder unit 22 of the engine 20 via an intake passage 40. One end portion of the intake passage 40 is connected to the cylinder unit 22. In side view, the intake passage 40 extends upward from the cylinder unit 22. The other end portion of the intake passage 40 is connected to the air cleaner 30. The air cleaner 30 cleans air to be supplied to the engine 20. Air is cleaned by being passed through the air cleaner 30, and is then supplied to the engine 20 through the intake passage 40. A front cover 11 (FIG. 1) is located forward of the head pipe 3, leftward of the air cleaner 30, rightward of the air cleaner 30, partially leftward of the engine 20 and partially rightward of the engine 20.
As illustrated in FIG. 1, the seat frame 5 extends obliquely upward and rearward from a position somewhere along the main frame 4 in side view. The seat 9 is located above the seat frame 5. The seat 9 is supported by the seat frame 5. A rear cushion unit 13 is located below the seat frame 5. The rear cushion unit 13 is supported at its upper end portion by the seat frame 5, and is supported at its lower end portion by a rear frame 14. The rear frame 14 is provided at its front portion with a pivot shaft 14a. The rear frame 14 is swingable up and down around the pivot shaft 14a. At a rear portion of the rear frame 14, a rear wheel 15 is supported. A body cover 16 is located laterally of the main frame 4 and seat frame 5 of the body frame 2.
As illustrated in FIG. 2, the main frame 4 is provided with a bracket 17. The bracket 17 extends downward from the main frame 4. The engine 20 includes a crankcase 18. At an upper front portion of the crankcase 18, a boss portion (not illustrated) is formed. The boss portion of the crankcase 18 is fixed to the bracket 17 by a bolt 18a so as not to be swingable. Although not illustrated, a rear portion of the crankcase 18 is also fixed to another bracket by a bolt so as not to be swingable. Thus, the engine 20 is supported by the body frame 2 so as not to be swingable. The crankcase 18 incorporates unillustrated components such as a crankshaft and a transmission mechanism.
The engine 20 further includes: a cylinder block 24 extending forward from the crankcase 18; a cylinder head 26 fixed to a front end portion of the cylinder block 24; and a head cover 28 fixed to a front end portion of the cylinder head 26. The cylinder block 24, the cylinder head 26 and the head cover 28 constitute the cylinder unit 22. It is to be noted that any two or three of the cylinder block 24, the cylinder head 26 and the head cover 28 may be formed integrally with each other. The number of members constituting the cylinder unit 22 is not limited in any way. The cylinder unit 22 is located forward of the crankcase 18. The entire cylinder unit 22 may be formed separately from the crankcase 18. Alternatively, part of the cylinder unit 22 may be formed integrally with the crankcase 18. The cylinder unit 22 is located lower than a bottom surface 12a of the concave region 12. A center line of the cylinder block 24, i.e., a cylinder axis L1, extends obliquely forward and upward. In this embodiment, the cylinder axis L1 has an inclination angle of about 10° relative to a horizontal line, and thus extends substantially horizontally. The inclination angle of the cylinder axis L1 may be 10° or less, 15° or less, or 30° or less, for example.
FIG. 3 is a left side cross-sectional view of part of the cylinder unit 22 and part of the intake passage 40. As illustrated in FIG. 3, in the cylinder head 26, a combustion chamber 23 and an intake port 25, at least partially located more forward than the combustion chamber 23, are formed. The intake port 25 is formed in an upper half portion of the cylinder head 26. The intake port 25 is bent. In this embodiment, the intake port 25 extends obliquely forward and upward from the combustion chamber 23, and then extends upward. Between the intake port 25 and the combustion chamber 23, there is formed an opening 27b. The opening 27b is opened and closed by an intake valve 27. The intake valve 27 has an umbrella-like valve body 27a and a rod-like stem 27d. The intake valve 27 is driven by a camshaft 27c via an unillustrated rocker arm. With a rotation of the camshaft 27c, the intake valve 27 moves back and forth relative to the opening 27b along an axial direction of the stem 27d. An axis 27e of the stem 27d has an inclination angle θ1 ranging from 30° to 40°, for example, with respect to a horizontal line.
Although not illustrated, in a lower half portion of the cylinder head 26, an exhaust port located more forward than the combustion chamber 23 is formed. Between the exhaust port and the combustion chamber 23, there is formed another opening. This opening is opened and closed by an unillustrated exhaust valve. The exhaust port is connected with an unillustrated exhaust pipe.
The opening 27b is formed at a lower end of the intake port 25. At an upper end of the intake port 25, a port connection opening 25a is formed. The port connection opening 25a is connected with a throttle body 44 via a first intake pipe 42. The throttle body 44 is provided at its upper end portion with an upper connection opening 44b. The upper connection opening 44b is connected with one end portion of a second intake pipe 46. The other end portion of the second intake pipe 46 is inserted into the air cleaner 30 through a connection opening 32 of the air cleaner 30 (see FIGS. 2 and 8). The first intake pipe 42, the throttle body 44 and the second intake pipe 46 constitute the intake passage 40. As illustrated in FIG. 2, a lower portion of the intake passage 40 is located between the engine 20 and the main frame 4.
As illustrated in FIG. 3, the throttle body 44 has a cylindrical shape. At a longitudinal center of the throttle body 44, a single throttle valve 43 is located. The throttle valve 43 includes: a valve shaft 43b; and a valve plate 43a fixed to the valve shaft 43b. The throttle body 44 is provided at its lower end portion with a lower connection opening 44a connected to the first intake pipe 42, and is provided at its upper end portion with the upper connection opening 44b connected to the second intake pipe 46. The throttle body 44 is located above the intake port 25 and placed in a standing position. In other words, as illustrated in FIGS. 3 and 4, the throttle body 44 is located so that when viewed from above the motorcycle 1, the upper connection opening 44b, the lower connection opening 44a and the intake port 25 are at least partially overlapped with each other. Thus, a space is ensured in front of the throttle body 44. Utilizing this space, an injector 50 is located so as to be at least partially located more forward than the throttle body 44. The throttle body 44 is provided at its front portion with an injector placement portion 47. Although not illustrated in FIG. 4, the injector 50 is inserted into a hole 47a formed in the injector placement portion 47.
As illustrated in FIG. 4, when viewed from above the motorcycle 1, a front end of the port connection opening 25a is located more forward than a front end of the lower connection opening 44a. A rear end of the lower connection opening 44a is located more rearward than a front end of the upper connection opening 44b. The front end of the upper connection opening 44b is located more forward than a rear end of the port connection opening 25a. The rear end of the lower connection opening 44a is located at substantially the same position as the rear end of the port connection opening 25a, or located more rearward than the rear end of the port connection opening 25a. The rear end of the port connection opening 25a is located more forward than a center 44bA of the upper connection opening 44b. The rear end of the lower connection opening 44a is located more forward than the center 44bA of the upper connection opening 44b. The front end of the upper connection opening 44b is located at the same position as a center 25aA of the port connection opening 25a, or located more rearward than the center 25aA. The port connection opening 25a has a diameter smaller than that of the upper connection opening 44b. The diameter of the port connection opening 25a is larger than that of the lower connection opening 44a. When viewed from above the motorcycle 1, the center 44bA of the upper connection opening 44b, a center of the lower connection opening 44a, and the center 25aA of the port connection opening 25a are located on a straight line L3. On the straight line L3, a center of the hole 47a of the injector placement portion 47 is also located.
In this embodiment, as illustrated in FIG. 3, the throttle body 44 is inclined rearward so that in side view, a front end 44g of a lower edge of the throttle body 44 is located more forward than a front end 44c of an upper edge of the throttle body 44, and a rear end 44h of the lower edge is located more forward than a rear end 44f of the upper edge. That is to say, the throttle body 44 is inclined with respect to a vertical direction so as to be located more rearward as it extends upward. The front end 44g of the lower edge of the throttle body 44 is located higher than the rear end 44h of the lower edge, and the front end 44c of the upper edge is located higher than the rear end 44f of the upper edge. For example, an axis 44L of the throttle body 44 may be inclined rearward at an angle θ2 ranging from 5° to 30° with respect to a vertical axis. The angle θ2 may be in the range of 5° to 15°. Thus, in contrast to a case where the axis 44L of the throttle body 44 coincides with the vertical axis, an increase in height of the throttle body 44 (or in vertical length of the throttle body 44) can be prevented while a length A1 of the throttle body 44 is ensured. For example, the throttle body 44 may have the length A1 equal to or less than 1.5 times (e.g. , about 1.3 times) a length A2 of the injector 50. The front end 44c of the upper edge of the throttle body 44 (i.e., an upper end of the throttle body 44) is located lower than an upper end 50a of the injector 50.
As illustrated in FIG. 3, the injector 50 is attached to the throttle body 44 so as to be at least partially located more forward than the throttle body 44. In the present embodiment, the entire injector 50 is located more forward than the throttle valve 43. The injector 50 injects fuel toward the intake port 25. In this embodiment, the throttle body 44 is provided at its front portion with the injector placement portion 47. In the injector placement portion 47, the hole 47a extending obliquely downward is formed. The injector 50 is fixed by being inserted into the hole 47a. A tip end portion 52 of an injection nozzle of the injector 50 is located in the vicinity of an inner surface of the throttle body 44. When the motorcycle 1 is viewed laterally, the injector 50 is located so that an extension L2 of an axis of the injector 50 intersects the opening 27b. In other words, the extension L2 of the axis of the injector 50 extends toward a back surface of the valve body 27a of the intake valve 27 in a fully closed position. The injector 50 is located at a position from which fuel can be directly supplied to the combustion chamber 23 when the intake valve 27 is opened. The extension L2 of the axis of the injector 50 preferably forms an angle ranging from 30° to 40° with respect to the axis 27e of the stem 27d of the intake valve 27. Thus, an injection direction of the injector 50 can be further directed toward the combustion chamber 23.
In this embodiment, the extension L2 of the axis of the injector 50 does not overlap with the stem 27d of the fully closed intake valve 27. In this embodiment, the extension L2 of the axis of the injector 50 extends toward an upper portion of the valve body 27a of the fully closed intake valve 27. In other words, the extension L2 of the axis of the injector 50 passes through an upper half region of the opening 27b when the intake valve 27 is opened. However, the direction of the extension L2 is not limited to the above direction. For example, the extension L2 of the axis of the injector 50 may intersect an inner surface of the intake port 25. Also in such a case, fuel injected from the injector 50 is guided downward by air flowing through the intake port 25, thus allowing fuel to be effectively supplied to the combustion chamber 23. The injector 50 has an injection width W expanded gradually from the tip end portion 52 of the nozzle toward the opening 27b. When viewed in the fuel injection direction, the injection width W of the injector 50 is smaller than an inner diameter of the port connection opening 25a, and is approximately equal to or smaller than an inner diameter of the opening 27b. Thus, fuel can be supplied more directly to the combustion chamber 23.
The injector 50 is substantially vertically extended, but is inclined forward so that a front end 50b of a lower edge of the injector 50 is located more rearward than a front end 50c of an upper edge of the injector 50, and a rear end 50d of the lower edge is located more rearward than a rear end 50a of the upper edge. That is to say, the injector 50 is inclined with respect to a vertical direction so as to be located more forward as it extends upward. Thus, the front end 50b of the lower edge of the injector 50 is located lower than the rear end 50d of the lower edge, and the front end 50c of the upper edge is located lower than the rear end 50a of the upper edge. For example, the axis of the injector 50 may have an inclination angle in the range of 10° to 30° or in the range of 15° to 25° with respect to a vertical axis. The injector 50 is located in the forwardly-inclined position in this manner, thereby allowing the injection direction of the injector 50 to be further directed toward the combustion chamber 23. Furthermore, the injector 50 can be reduced in vertical length.
The first intake pipe 42 serves as a member interposed between the throttle body 44 and the cylinder head 26. In the present embodiment, the first intake pipe 42 is formed separately from the throttle body 44 and then fitted to the throttle body 44. However, the first intake pipe 42 may be formed integrally with the throttle body 44. Although not illustrated, in the present embodiment, the first intake pipe 42 includes: a core made of a resin; and heat-resistant rubber located around the core. The first intake pipe 42 is formed into a cylindrical shape and is connected to the port connection opening 25a of the intake port 25. The lower connection opening 44a of the throttle body 44 is inserted into an upper connection opening 42a of the first intake pipe 42. The first intake pipe 42 and the throttle body 44 are fixed to each other by a fixation band (not illustrated). The first intake pipe 42 is interposed between the throttle body 44 and the intake port 25 in this manner, thus making it possible to suppress influence of heat of the engine 20 exerted on the injector 50. That is to say, heating of the injector 50 by the engine 20 is suppressed. As a result, an excessive increase in temperature of the injector 50 is prevented. Furthermore, the first intake pipe 42 includes the rubber (heat-resistant rubber) and thus can absorb vibration of the engine 20. Therefore, the injector 50 is unlikely to be influenced by vibration of the engine 20. In this embodiment, the first intake pipe 42 extends straightly from the throttle body 44 to the intake port 25. A region of the first intake pipe 42, located in the vicinity of the port connection opening 25a, is substantially straightly formed. A region of the intake passage 40, located in the vicinity of the engine 20, is straightly formed in this manner, thus making it possible to reduce flow resistance of air sucked into the engine 20, compared with a case where the region of the intake passage 40 located in the vicinity of the engine 20 is bent. As a result, intake efficiency of the engine 20 is improved.
The first intake pipe 42 has a length A3 shorter than the length A1 of the throttle body 44. For example, the length A3 of the first intake pipe 42 is 0.1 to 0.4 times (e.g., 0.2 to 0.3 times) the length A1 of the throttle body 44. The first intake pipe 42 is sufficiently short, thus allowing the injector 50 to be located close to the combustion chamber 23. Therefore, fuel can be more directly supplied to the combustion chamber 23 from the injector 50. Note that when the injector 50 is located close to the combustion chamber 23, the injector 50 may be increased in temperature, and bubbles might be generated in fuel. However, in the present embodiment, the injector 50 is located more forward than the throttle body 44; hence, when the motorcycle 1 runs, wind blows from the front, and thus the injector 50 can be cooled by the wind. Consequently, generation of bubbles in fuel can be prevented.
FIGS. 5A and 5B are right side views of components such as the first intake pipe 42 and the engine 20. FIGS. 6A and 6B are left side views of components such as the first intake pipe 42 and the engine 20. As illustrated in FIGS. 5B and 6B, the first intake pipe 42 has a flange portion 42c. The flange portion 42c is formed at a lower end of the first intake pipe 42. The flange portion 42c is fixed to a peripheral edge of the port connection opening 25a (FIG. 3) of the cylinder head 26 by using an unillustrated bolt. In side view, a joint plane B between the first intake pipe 42 and the cylinder head 26 is located lower than a border line 26L of an upper wall 26a of the cylinder head 26. In other words, when the motorcycle 1 is viewed laterally, a lower end face 42b of the first intake pipe 42 is located lower than the border line 26L of the upper wall 26a of the cylinder head 26. The lower end face 42b of the first intake pipe 42 is inserted into the cylinder head 26. This allows the first intake pipe 42 and the throttle body 44 to be located at lower positions.
As illustrated in FIG. 2, the second intake pipe 46 extends upward from the throttle body 44. A material for the second intake pipe 46 is not particularly limited. For example, the second intake pipe 46 may be a resin duct, a metal pipe or a rubber hose. When the motorcycle 1 is viewed laterally, the second intake pipe 46 extends obliquely upward and forward along the main frame 4. The air cleaner 30 is at least partially located below a front portion of the main frame 4 and rearward of the head pipe 3. Furthermore, the air cleaner 30 is at least partially located below the head pipe 3. In this embodiment, a front end 34c of the air cleaner 30 is located more rearward than a front end 3a of the head pipe 3 and more forward than a rear end 3b of the head pipe 3. The air cleaner 30 is fixed to the main frame 4 by a bolt. At a rear portion of the air cleaner 30, the connection opening 32 is formed (see FIG. 8). The second intake pipe 46 is connected to the connection opening 32 of the air cleaner 30.
FIG. 7 is a rear view of components such as the air cleaner 30 and the main frame 4. FIG. 8 is a diagram equivalent to FIG. 7, from which the main frame 4 is removed. FIG. 9 is a left side view of the air cleaner 30 and its surroundings. And FIG. 10 is a top cross-sectional view of the air cleaner 30. As illustrated in FIG. 10, the air cleaner 30 has: an air cleaner case 34; and an element 36 located inside the air cleaner case 34. As illustrated in FIG. 9, the air cleaner case 34 includes a front case member 34A and a rear case member 34B. As illustrated in FIG. 8, the air cleaner case 34 further includes two ducts 38L and 38R.
As illustrated in FIGS. 8 and 9, at an upper surface of the air cleaner case 34, a groove 35 is formed at a position facing the main frame 4. The groove 35 is provided so as to surround part of lower and lateral surfaces of the main frame 4. The groove 35 extends obliquely downward and rearward along the main frame 4. The main frame 4 is at least partially located inside the groove 35. In the present embodiment, a lower portion of the main frame 4 is partially located inside the groove 35. The front case member 34A is located forward of the rear case member 34B. Upper ends 34Aa of the front case member 34A are located higher than upper ends 34Ba of the rear case member 34B. In side view, upper portions of the front case member 34A overlap with the main frame 4 (see FIG. 9). At the upper portions of the front case member 34A, openings 33a and 33b are formed. The openings 33a and 33b are formed at symmetrical positions, with the main frame 4 sandwiched therebetween. The ducts 38L and 38R are attached to the openings 33a and 33b, respectively. The ducts 38L and 38R each extend obliquely downward and rearward from the front case member 34A. The reference sign "94" in FIG. 9 represents a harness in which wires of the motorcycle 1 are bound together. In side view, the harness 94 extends obliquely downward and rearward along the main frame 4.
As illustrated in FIG. 8, the connection opening 32 of the air cleaner 30 is formed at a position located in a lower rear portion of the rear case member 34B and at a lateral surface of the groove 35. The connection opening 32 is opened obliquely rightward and downward. Furthermore, the connection opening 32 is located higher than a lower surface 34a of the air cleaner case 34, and located leftward of the main frame 4 (see FIG. 7) . When viewed from behind the motorcycle 1, the second intake pipe 46 is extended upward from the throttle body 44 so as to be inclined leftward toward the connection opening 32 and connected thereto. That is to say, the second intake pipe 46 extends leftward as it extends upward from the throttle body 44, and is then connected to the connection opening 32 of the air cleaner 30. Note that the connection opening 32 of the air cleaner 30 may be located rightward of the main frame 4. In that case, when viewed from behind the motorcycle 1, the second intake pipe 46 extends rightward as it extends upward from the throttle body 44, and is then connected to the connection opening 32. The connection opening 32 is offset leftward or rightward from a center of the main frame 4 in this manner, thereby allowing the second intake pipe 46 to be increased in length. Therefore, even when the first intake pipe 42 is short, an overall length of the intake passage 40 can be sufficiently ensured.
As illustrated in FIG. 9, when the motorcycle 1 is viewed laterally, the second intake pipe 46 extends obliquely upward and forward inside the air cleaner 30. As illustrated in FIGS. 8 and 10, the second intake pipe 46 extends leftward from the connection opening 32, and is then bent to extend rightward. As illustrated in FIG. 10, in this embodiment, the second intake pipe 46 has: a bent portion 46b; and an extended portion 46c extended rightward from an end of the bent portion 46b. The bent portion 46b is approximately U-shaped when viewed from above the motorcycle 1, and is located leftward of the main frame 4.
The extended portion 46c extends straightly rightward from the end of the bent portion 46b. When viewed from behind the motorcycle 1, the extended portion 46c extends from a position leftward of the main frame 4 to a position rightward of the main frame 4. When viewed from above the motorcycle 1, the extended portion 46c is located so as to extend transversely under the main frame 4. At an end of the extended portion 46c, an intake opening 46d is formed. The intake opening 46d is located opposite to the bent portion 46b relative to the main frame 4. As illustrated in FIG. 8, when viewed from behind the motorcycle 1, the intake opening 46d is located in an upper portion of the rear case member 34B and below the duct 38R. The intake opening 46d is opened rightward. The bent portion 46b and the extended portion 46c are located downstream of the element 36 inside the air cleaner 30. In other words, the bent portion 46b and the extended portion 46c are located at a "clean side" inside the air cleaner 30. Air introduced into the air cleaner 30 through the ducts 38L and 38R is guided to a region forward of the element 36 through the openings 33a and 33b. The air rearwardly passes through the element 36 and is thus cleaned by the element 36. The air, which has passed through the element 36, is introduced into the second intake pipe 46 from the intake opening 46d. The introduced air is guided to the intake port 25 of the engine 20 via the second intake pipe 46, the throttle body 44 and the first intake pipe 42.
As illustrated in FIG. 2, when the motorcycle 1 is viewed laterally, the second intake pipe 46 is located so as to be overlapped with the main frame 4. Specifically, the second intake pipe 46 has an overlapping portion 46e overlapping with the main frame 4 along a vertical direction. As the second intake pipe 46 and the main frame 4 are overlapped with each other along the vertical direction, an installation space for the injector 50 can be ensured below the second intake pipe 46 accordingly. FIG. 11 is a rear perspective view of the second intake pipe 46 and its surroundings. FIG. 12 is an enlarged view of the main parts of FIG. 11. And FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 12. As illustrated in FIGS. 11 to 13, at an outer wall of the second intake pipe 46, a concave portion 46f facing the main frame 4 is formed. In this embodiment, the concave portion 46f is formed at an outer wall of a region of the second intake pipe 46 located between the throttle body 44 and the connection opening 32. The concave portion 46f and the main frame 4 have a gap therebetween. The concave portion 46f is formed at the outer wall of the second intake pipe 46 in this manner, thereby making it possible to increase a bend radius of the second intake pipe 46 while avoiding interference between the second intake pipe 46 and the main frame 4. Hence, intake efficiency is further improved.
Note that as illustrated in FIG. 2, the air cleaner 30 is at least partially provided above the throttle body 44. More specifically, a rear end 34b of the air cleaner 30 is located more rearward than a front extremity 44d of the throttle body 44 and more forward than a rear extremity 44e of the throttle body 44. The air cleaner 30 is located forward of the concave region 12. The lower surface 34a of the air cleaner 30 is located at the same height as that of the bottom surface 12a of the concave region 12. The throttle body 44 is at least partially located lower than the bottom surface 12a of the concave region 12. The injector 50 is located below the air cleaner 30 and the second intake pipe 46, and above the cylinder head 26. In this embodiment, the injector 50 is located below the rear portion of the air cleaner 30, and located more forward than the rear end 34b of the air cleaner 30. Furthermore, the injector 50 is located lower than the bottom surface 12a of the concave region 12.
In the motorcycle 1 according to the present embodiment, as illustrated in FIG. 1, the concave region 12 is formed rearward of the head pipe 3, forward of the seat 9 and above the main frame 4 when the motorcycle 1 is viewed laterally. Therefore, a rider can easily straddle the main frame 4 when getting on the motorcycle 1, and thus can easily get on and off the motorcycle 1. As illustrated in FIGS. 3 and 4, the throttle body 44 is located so that the upper connection opening 44b, the lower connection opening 44a and the intake port 25 at least partially overlap with each other when viewed from above the motorcycle 1. The injector 50 is at least partially located more forward than the throttle body 44, and the injector 50 injects fuel toward the intake port 25. Therefore, the injector 50 can be further directed toward the combustion chamber 23. For example, fuel can be more directly supplied to the combustion chamber 23. Accordingly, the motorcycle 1 is capable of improving fuel efficiency while allowing a rider to get on and off the motorcycle 1 easily.
For example, if the entire injector 50 is located more rearward than the throttle body 44, the first intake pipe 42 has to be significantly bent forward in order to ensure an installation space for the injector 50. However, in the motorcycle 1, the injector 50 is at least partially located more forward than the throttle body 44. Therefore, the first intake pipe 42 does not have to be significantly bent forward. Accordingly, the degree of bending of the first intake pipe 42 can be reduced, and air is allowed to flow more smoothly through the first intake pipe 42. As a result, an improvement in intake efficiency is enabled.
Moreover, in the motorcycle 1, the throttle body 44 extends approximately vertically upward, thus making it possible to sufficiently ensure an installation space for the injector 50 in front of the throttle body 44. Besides, since the injector 50 is at least partially located more forward than the throttle body 44, wind flowing from the front due to running of the motorcycle 1 is likely to be directly blown against the injector 50. Therefore, the injector 50 can be efficiently cooled by wind. Accordingly, an increase in temperature of the injector 50 can be suppressed, and generation of bubbles in fuel can be inhibited. As a result, injection performance of the injector 50 can be favorably maintained.
FIG. 14 is a perspective view of the motorcycle 1. It is to be noted that illustration of components inside the front cover 11 is omitted. As illustrated in FIG. 14, the front cover 11 is opened forward. The fender 10 and the front cover 11 have a gap 19 therebetween. FIG. 15 is an enlarged view of a region XV of FIG. 14. The front cover 11 is provided rightward and leftward of the air cleaner 30. The injector 50 is located below the air cleaner 30 and forward of the throttle body 44, and faces a rear surface of the fender 10. Through the gap 19 between the fender 10 and the front cover 11, spaces diagonally forward of the injector 50 are widely open. When an inspection is performed on the engine 20, a tool or a hand can be inserted and withdrawn from in front of the front cover 11 by utilizing the gap 19. The injector 50 can be easily detached from and attached to a position forward of the throttle body 44 without having to remove the front cover 11. Accordingly, maintenance of the injector 50 can be easily performed. Note that the reference sign "90" represents a fuel hose through which fuel is supplied to the injector 50. As illustrated in FIG. 1, when the motorcycle 1 is viewed laterally, the fuel hose 90 extends obliquely upward and rearward along the seat frame 5. The fuel hose 90 is connected to a fuel pump (not illustrated) inside a fuel tank 92 located below the seat 9.
In this embodiment, as illustrated in FIG. 3, the opening 27b opened and closed by the intake valve 27 is formed between the intake port 25 and the combustion chamber 23. The injector 50 is located so that the extension L2 of the axis of the injector 50 intersects the opening 27b. This allows the injection direction of the injector 50 to be further directed toward the combustion chamber 23, thereby realizing more favorable fuel injection. Hence, fuel efficiency is further improved.
As illustrated in FIG. 1, in the underbone type motorcycle 1, the concave region 12 is formed rearward of the head pipe 3, forward of the seat 9 and above the main frame 4 when the motorcycle 1 is viewed laterally. Thus, a region of the main frame 4, located between the seat 9 and the handlebar 7, is reduced in height. As illustrated in FIG. 2, the air cleaner 30 is located below the main frame 4 and higher than the cylinder head 26. Therefore, a space formed below the air cleaner 30 and above the cylinder unit 22 is small.
However, in the present embodiment, as illustrated in FIG. 3, the throttle body 44 is inclined rearward so that when the motorcycle 1 is viewed laterally, the front end 44g of the lower edge of the throttle body 44 is located more forward than the front end 44c of the upper edge of the throttle body 44, and the rear end 44h of the lower edge is located more forward than the rear end 44f of the upper edge. That is to say, the throttle body 44 is inclined with respect to the vertical direction so as to be located more rearward as it extends upward. This can reduce the vertical length of the throttle body 44. Further, the injector 50 can be compactly located by utilizing the space forward of the throttle body 44. Therefore, it is unnecessary to raise the position of the concave region 12. Since the concave region 12 can be maintained at a low position, a rider is allowed to get on and off the motorcycle 1 with sufficient ease.
The injector 50 is inclined forward so that the front end 50b of the lower edge of the injector 50 is located more rearward than the front end 50c of the upper edge of the injector 50, and the rear end 50d of the lower edge is located more rearward than the rear end 50a of the upper edge. That is to say, the injector 50 is inclined with respect to the vertical direction so as to be located more forward as it extends upward. This allows the injection direction of the injector 50 to be further directed toward the combustion chamber 23, thereby realizing more favorable fuel injection. Hence, fuel efficiency is further improved. In addition, the vertical length of the injector 50 can be reduced. Therefore, the concave region 12 can be maintained at a low position, thus allowing a rider to get on and off the motorcycle 1 with sufficient ease.
In the present embodiment, the single throttle valve 43 is incorporated into the throttle body 44 and thus the length A1 of the throttle body 44 is shortened. The length A1 of the throttle body 44 is equal to or less than 1.5 times the length A2 of the injector 50. Therefore, the throttle body 44 can be easily located in a small space between the main frame 4 and the cylinder head 26.
In this embodiment, the length A3 of the first intake pipe 42 is shorter than the length A1 of the throttle body 44. The length A3 of the first intake pipe 42 is shortened in this manner, thereby allowing the injector 50 to be located close to the combustion chamber 23. Therefore, the injector 50 can be further directed toward the combustion chamber 23, thereby further improving fuel efficiency.
As illustrated in FIG. 5B, when the motorcycle 1 is viewed laterally, the lower end face 42b of the first intake pipe 42 is located below the border line 26L of the upper wall 26a of the cylinder head 26. This allows the first intake pipe 42 and the throttle body 44 to be located at lower positions. Therefore, an installation space for the throttle body 44 and the injector 50 can be sufficiently ensured below the main frame 4. As a result, the throttle body 44 and the injector 50 can be compactly located while a rider is allowed to easily get on and off the motorcycle 1.
As illustrated in FIGS. 7 and 8, the connection opening 32, located leftward of the main frame 4, is formed in the air cleaner 30. When viewed from behind the motorcycle 1, the second intake pipe 46 is extended upward from the throttle body 44 so as to be inclined leftward toward the connection opening 32 and connected thereto. This can increase the length of the second intake pipe 46 compared with a case where the second intake pipe 46 extends straightly forward as it extends upward. Therefore, even when the first intake pipe 42 is short, the overall length of the intake passage 40 can be sufficiently ensured. Accordingly, intake characteristics of the engine 20 can be favorably maintained. Since the second intake pipe 46 extends obliquely upward from the throttle body 44, the second intake pipe 46 can be reduced in lateral dimension compared with a case where the second intake pipe 46 extends laterally from the throttle body 44. Note that although the connection opening 32 is formed leftward of the main frame 4 in the present embodiment, the connection opening 32 may be formed rightward of the main frame 4. In that case, the second intake pipe 46 is extended upward from the throttle body 44 so as to be inclined rightward toward the connection opening 32 and connected thereto. Also in such a case, the above-described effects are obtainable.
In this embodiment, the connection opening 32 of the air cleaner 30 is formed at the rear portion of the air cleaner 30. The connection opening 32 is located higher than the lower surface 34a of the air cleaner 30. Thus, a region of the second intake pipe 46, located outside the air cleaner 30, can be reduced. Therefore, a space located between the main frame 4 and the cylinder unit 22 and occupied by the second intake pipe 46 can be reduced, and thus the installation space for the injector 50 can be sufficiently ensured.
When viewed from behind the motorcycle 1, the second intake pipe 46 extends leftward as it extends upward from the throttle body 44, and is then bent rightward inside the air cleaner 30 (see FIG. 10). Inside the air cleaner 30, the second intake pipe 46 is bent by 90° or more. This can further increase the length of the second intake pipe 46 without increasing the space occupied by the region of the second intake pipe 46 located outside the air cleaner 30, and thus can sufficiently ensure the overall length of the intake passage 40. Note that the bending angle of the second intake pipe 46 inside the air cleaner 30 is not particularly limited. For example, the bending angle may be 120° or more, or may be 135° or more. In the present embodiment, the entire second intake pipe 46 (including the regions thereof located inside and outside the air cleaner 30) is bent by 180°. However, the bending angle of the entire second intake pipe 46 is also not particularly limited.
Inside the air cleaner 30, the second intake pipe 46 extends from a position leftward of the main frame 4 to a position rightward of main frame 4. Specifically, when viewed from above, the second intake pipe 46 is located so as to extend transversely under the main frame 4. This can further increase the length of the second intake pipe 46 without increasing the space occupied by the region of the second intake pipe 46 located outside the air cleaner 30, and thus can sufficiently ensure the overall length of the intake passage 40. Note that when the connection opening 32 is formed rightward of the main frame 4, the second intake pipe 46 may be located so as to extend from a position rightward of the main frame 4 to a position leftward of the main frame 4 inside the air cleaner 30. Also in such a case, the above-described effects are obtainable.
As illustrated in FIG. 2, the second intake pipe 46 is located so as to be overlapped with the main frame 4 when the motorcycle 1 is viewed laterally. As the second intake pipe 46 and the main frame 4 are overlapped with each other along the vertical direction, the installation space for the injector 50 can be ensured below the second intake pipe 46 accordingly. Furthermore, the length of the second intake pipe 46 can be increased, and thus the overall length of the intake passage 40 can be sufficiently ensured.
As illustrated in FIGS. 12 and 13, the concave portion 46f facing the main frame 4 is formed at the outer wall of the second intake pipe 46. This can increase the degree of bending of the second intake pipe 46 while avoiding interference between the second intake pipe 46 and the main frame 4. Hence, intake efficiency can be further improved.
As illustrated in FIG. 2, the rear end 34b of the air cleaner 30 is located more rearward than the front extremity 44d of the throttle body 44, and more forward than the rear extremity 44e of the throttle body 44. This can shorten an overall fore-and-aft length of the air cleaner 30 and the throttle body 44. Hence, the air cleaner 30 and the intake passage 40 can be compactly located while a volume of the air cleaner 30 is ensured.
The injector 50 is located below the air cleaner 30. This allows a space, located below the air cleaner 30 and forward of the throttle body 44, to be effectively utilized as the installation space for the injector 50. Thus, the injector 50 can be compactly located. Besides, wind flowing from the front due to running of the motorcycle 1 blows against the lower surface 34a of the air cleaner case 34 or flows along the lower surface 34a, and thus the wind is guided toward the injector 50. The lower surface 34a of the air cleaner case 34 functions as a baffle plate, thereby making it possible to further facilitate cooling of the injector 50.

FIG. 16 is a schematic left side cross-sectional view of the throttle body 44 of a motorcycle according to Embodiment 2, and its surroundings. As illustrated in FIG. 16, in Embodiment 2, the injector 50, attached to the throttle body 44 in Embodiment 1, is attached to the first intake pipe 42. Specifically, the injector 50 is attached to the first intake pipe 42 so as to be at least partially located more forward than the throttle body 44. Other features are similar to those of Embodiment 1, and therefore, description thereof will be omitted.
In the motorcycle according to Embodiment 2, the injector 50 is attached to the first intake pipe 42 so as to be at least partially located more forward than the throttle body 44. Therefore, the injector 50 can be located closer to the combustion chamber 23. Accordingly, the injector 50 can be further directed toward the combustion chamber 23, thereby further improving fuel efficiency.

1	motorcycle
3	head pipe
4	main frame
20	engine
22	cylinder unit
23	combustion chamber
25	intake port
26	cylinder head
27	intake valve
30	air cleaner
40	intake passage
42	first intake pipe
44	throttle body
46	second intake pipe
50	injector

Claims

A motorcycle comprising:
a body frame having a head pipe, and a main frame extending obliquely downward and rearward from the head pipe;

a seat supported by the body frame and located rearward of the head pipe;

an engine having a cylinder unit located below the main frame, the engine being supported by the main frame so as not to be swingable;

an air cleaner at least partially located below the main frame and higher than the cylinder unit; and

an intake passage connected to the cylinder unit and the air cleaner,

wherein when the motorcycle is viewed laterally, a concave region is formed rearward of the head pipe, forward of the seat and above the main frame,

wherein inside the cylinder unit, there are formed a combustion chamber and an intake port at least partially located more forward than the combustion chamber,

wherein the intake passage has: a first intake pipe connected to the intake port; a throttle body connected to the first intake pipe and incorporating a throttle valve; and a second intake pipe connected to the throttle body and the air cleaner,

wherein the throttle body is provided at its lower end portion with a lower connection opening connected to the first intake pipe, and is provided at its upper end portion with an upper connection opening connected to the second intake pipe,

wherein the upper connection opening, the lower connection opening and the intake port are located so as to be at least partially overlapped with each other when viewed from above the motorcycle, and

wherein the motorcycle further comprises an injector for injecting fuel toward the intake port, the injector being attached to the throttle body or the first intake pipe so as to be at least partially located more forward than the throttle body.
A motorcycle according to Claim 1,
wherein the throttle body comprises an upper edge and a lower edge, and
wherein the throttle body is inclined rearward so that a front end of the lower edge is located more forward than a front end of the upper edge, and a rear end of the lower edge is located more forward than a rear end of the upper edge.
A motorcycle according to Claim 1 or 2,
wherein the injector comprises an upper edge and a lower edge, and
wherein the injector is inclined forward so that a front end of the lower edge is located more rearward than a front end of the upper edge, and a rear end of the lower edge is located more rearward than a rear end of the upper edge.
A motorcycle according to any one of Claims 1 to 3,
wherein between the intake port and the combustion chamber, there is formed an opening opened and closed by an intake valve, and
wherein the injector is located so that an extension of an axis of the injector intersects the opening.
A motorcycle according to any one of Claims 1 to 4,
wherein when the motorcycle is viewed laterally, a lower end face of the first intake pipe is located below a border line of an upper wall of the cylinder unit.
A motorcycle according to any one of Claims 1 to 5,
wherein the throttle body has a length equal to or less than 1.5 times that of the injector.
A motorcycle according to any one of Claims 1 to 6,
wherein the first intake pipe has a length shorter than that of the throttle body.
A motorcycle according to any one of Claims 1 to 7,
wherein in the air cleaner, there is formed a connection opening located rightward or leftward of the main frame, and
wherein when viewed from behind the motorcycle, the second intake pipe is extended upward from the throttle body so as to be inclined rightward or leftward toward the connection opening and connected thereto.
A motorcycle according to Claim 8,
wherein the connection opening is formed at a rear portion of the air cleaner.
A motorcycle according to any one of Claims 1 to 9,
wherein the second intake pipe is bent by 90° or more inside the air cleaner.
A motorcycle according to any one of Claims 1 to 10,
wherein inside the air cleaner, the second intake pipe extends from a position leftward of the main frame to a position rightward of the main frame, or extends from a position rightward of the main frame to a position leftward of the main frame.
A motorcycle according to any one of Claims 1 to 11,
wherein the second intake pipe is located so as to be overlapped with the main frame when the motorcycle is viewed laterally.
A motorcycle according to any one of Claims 1 to 12,
wherein at an outer wall of the second intake pipe, there is formed a concave portion facing the main frame.
A motorcycle according to any one of Claims 1 to 13,
wherein a rear end of the air cleaner is located more rearward than a front extremity of the throttle body, and more forward than a rear extremity of the throttle body.
A motorcycle according to any one of Claims 1 to 14,
wherein the injector is located below the air cleaner.