JP2006248524A - Motorcycle engine mounting structure - Google Patents

Abstract

An object of the present invention is to provide a technique for improving riding comfort of a motorcycle in which a rear wheel support rear fork is attached to a crankcase so as to be swingable.
In a scooter type motorcycle provided with a footrest for placing a driver's foot between a seat and a handle, a front portion of a rear fork 88 supporting a rear wheel can swing up and down to a crankcase 52 of an engine 16 The engine 16 is disposed with the central axis of the crankshaft 61 directed in the vehicle width direction, and the engine 16 is attached to the vehicle body frames 112 and 115 via elastic members 131, 133, and 135. An engine mounting structure for a motorcycle that absorbs vibration transmitted in a direction orthogonal to a direction orthogonal to the crankshaft and absorbs vibration in the axial direction of the crankshaft.
[Selection] Figure 5

Description

  The present invention relates to an engine mounting structure for a motorcycle.

Some motorcycles have an engine mounted on a vehicle body frame and a rear fork mounted on the engine so as to be able to swing up and down (see, for example, Patent Document 1).
Japanese Patent Publication No. 1-333392

The prior art disclosed in Patent Document 1 relates to a stepping device for a seat-type motorcycle. As shown in FIG. 1 of the publication, the technique refers to a vehicle body 1 (numbers are those described in the publication). The same applies hereinafter.) The engine E is attached, the rear fork F is attached to the crankcase 18 of the engine E so as to be able to swing up and down, and the rear wheel Wr is attached to the rear part of the rear fork F so as to be rotatable.
Further, in the above prior art, as shown in FIG. 2 of the publication, an output shaft 19 for transmitting the power of the crankshaft 9 to the belt-type continuously variable transmission M is disposed behind the crankshaft 9, The center of the output shaft 19 is aligned with the swing center of the rear fork F.

In the case of the conventional technique, the rigidity of the vehicle body 1 is further increased by fixing the highly rigid engine E to the vehicle body 1 with bolts.
However, when the motorcycle is driven, the rear wheel Wr vibrates according to the road surface condition, and the vibration (hereinafter referred to as “traveling vibration”) is generated from the rear wheel Wr via the rear fork F and the engine E. It is transmitted directly to 1. Therefore, there is room for improvement in order to reduce the traveling vibration transmitted to the vehicle body 1 and increase the riding comfort of the motorcycle.

  It is an object of the present invention to provide a technique for improving riding comfort of a motorcycle in which a rear wheel support rear fork is attached to a crankcase so as to be swingable.

  According to a first aspect of the present invention, in a scooter type motorcycle provided with a footrest for placing a driver's foot between a seat and a steering wheel, a front fork of a rear fork that supports a rear wheel is swung up and down to a crankcase of an engine. The engine is disposed with the center axis of the crankshaft directed in the vehicle width direction, and the engine is attached to the vehicle body frame via an elastic member, and the elastic member transmits vibration transmitted in a direction perpendicular to the crankshaft. While absorbing, it is characterized by absorbing vibration in the axial direction of the crankshaft.

  According to a second aspect of the present invention, in the first aspect, the engine is attached to the vehicle body frame via a plurality of elastic members, and the elastic members are disposed above and below the cylinder axis in a side view. And

  According to a third aspect of the present invention, in the second aspect, the engine is attached to the vehicle body frame via an elastic member at a position apart from the vertical position of the cylinder axis in the front-rear direction. It is characterized by that.

  According to a fourth aspect of the present invention, in a scooter type motorcycle provided with a footrest for placing a driver's foot between a seat and a handle, a front fork of a rear fork that supports a rear wheel is swung up and down to a crankcase of an engine. The engine is arranged with the center axis of the crankshaft directed in the vehicle width direction, and the engine is provided with mounting support portions for attaching the engine to the vehicle body frame in front and rear of the crankshaft. The mounting support portion is attached to the vehicle body frame with a fastening member via an elastic member, and the elastic member absorbs vibrations in the axial direction and the radial direction of the fastening member.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the body frame is composed of a pair of left and right members, and the engine is a parallel multi-cylinder engine and extends in a substantially horizontal direction in a side view. The engine is fixed to the vehicle body frame such that the attachment portion of the engine to the vehicle body frame is sandwiched between the pair of left and right vehicle body frames.

  A sixth aspect of the present invention provides the engine according to any one of the first to fourth aspects, wherein the engine includes a belt-type transmission mechanism including a belt and a pulley, and a central axis of the driving pulley is disposed in parallel with the crankshaft. It is characterized by that.

  In the invention according to claim 1, the running vibration transmitted from the rear wheel via the rear fork and the left-right vibration by the engine can be mitigated by the elastic member.

  In the invention according to claim 2, since the elastic members are respectively arranged above and below the cylinder axis, the distance between the elastic members can be set larger, and as a result, the force acting on the elastic member is reduced. Therefore, the vibration absorbability of the elastic member is increased.

  In the invention according to claim 3, the traveling vibration transmitted from the rear fork to the engine can be further mitigated by the elastic member at the rear portion, and the riding comfort of the motorcycle can be further enhanced.

  In the invention which concerns on Claim 4, an engine can be firmly attached to a vehicle body frame, absorbing the left-right vibration transmitted to an engine.

  In the invention according to claim 5, by adopting a multi-cylinder engine with a wide left and right, the engine can be mounted between the left and right frames, and the fixation to the vehicle body can be strengthened.

  In the invention according to claim 6, in an engine having a belt-type transmission mechanism in which the central axis of the drive pulley is arranged parallel to the crankshaft, vibration in the left-right direction is likely to occur due to the movement of the drive pulley. The left-right vibration can be reliably reduced.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
“Front”, “Rear”, “Left”, “Right”, “Up”, “Down” follow the direction seen from the driver, Fr is front, Rr is rear, L is left, R is right , CL indicates the vehicle body center (vehicle width center).

FIG. 1 is a left side view of a motorcycle according to the present invention.
The motorcycle 10 includes a body frame 11, a front fork 13 attached to the head pipe 12 of the body frame 11, a front wheel 14 attached to the front fork 13, a handle 15 connected to the front fork 13, and a rear part of the body frame 11. An engine 16 attached to the engine 16, a power transmission mechanism 17 attached to the engine 16 so as to be able to swing up and down, a rear wheel 18 attached to the power transmission mechanism 17, and a rear end in which a rear end portion of the power transmission mechanism 17 is suspended from the body frame 11. The scooter type motorcycle includes a cushion unit 19, a storage box 21 attached to the upper rear portion of the vehicle body frame 11, and a seat 22 disposed on the storage box 21 and attached to be openable and closable. The sheet 22 is a double sheet.

  Furthermore, the motorcycle 10 has a body frame 11 covered with a body cover 30. The body cover 30 is disposed between the front cover 31 that covers the front portion of the head pipe 12, the inner cover 32 that covers the rear portion of the front cover 31, the handle 15 and the seat 22, and the left and right sides on which the driver's feet are placed. A low floor type footrest plate (floor step) 33, left and right floor skirts 34 extending downward from the outer edge of the low floor type footrest plate 33, and a center extending rearward from the inner cover 32 and covering the longitudinal center of the body frame 11 The cover 35 includes a rear cover 36 that extends rearward from the center cover 35 and covers the rear portion of the vehicle body frame 11.

  In the figure, 37 is a handle cover, 38 is a front fender, 39 is a rear fender, 41 is a wind screen, 42 is an engine cooling radiator, 43 is a fuel tank, 44 is a passenger step, 45 is an air cleaner, 46 is a connecting tube (connection) Tube), 47 is an air chamber, 48 is an engine exhaust pipe, and 49 is an exhaust silencer.

FIG. 2 is a left side view of the engine and the power transmission mechanism according to the present invention.
The engine 16 is a four-cycle two-cylinder water-cooled engine in which a cylinder 54 extends forward from the crankcase 52. Let the axis of the cylinder 54 be L1.

3 is a cross-sectional view taken along line 3-3 of FIG.
The case portion of the engine 16 includes a crankcase 52 formed by bolting the left and right case halves 51L and 51R, a cylinder block 53 bolted to the front of the crankcase 52, and a left and right two provided in the cylinder block 53. Cylinders 54, 54, a cylinder head 55 bolted to the front of the cylinder block 53, combustion chambers 56, 56 formed in the cylinder head 55, a head cover 57 bolted to the front of the cylinder head 55, It consists of a valve operating chamber 58 formed between the cylinder head 55 and the head cover 57.

Therefore, the engine 16 is a parallel multi-cylinder (two-cylinder in the figure) engine with a wide left and right, and the engine 16 is configured to extend in the front-rear direction substantially horizontally in a side view as shown in FIGS. 1, 2, and 5. ing. The engine 16 is mounted and supported so as to be sandwiched between a pair of left and right frame members 111, 111, 115, 115 as will be apparent from FIG.
The engine 16 further includes a crankshaft 61 that is rotatably attached to the crankcase 52 and extends left and right, and pistons 63 and 63 that are connected to the crankshaft 61 via connecting rods 62 and 62 and reciprocate in the cylinders 54 and 54. The valve operating mechanism 64 is housed in the valve operating chamber 58.

The generator cover 66 is bolted to the right side of the right case half 51R to form a generator storage chamber 67 between the right case half 51R and the generator cover 66, and the generator 68 is placed in the generator storage chamber 67. Stowed. The generator 68 is connected to the right end portion of the crankshaft 61.
Since the generator cover 66 is fixed to the crankcase 52, it is assumed that it is a part of the crankcase 52 in the present invention.

The power transmission mechanism 17 is attached to the left case half 51L via a bearing 71 so that the front part can swing up and down and the rear part of the transmission mechanism case 72 is closed. 73, a transmission mechanism storage chamber 74 formed between the transmission mechanism case 72 and the case cover 73, and a transmission mechanism 75 stored in the transmission mechanism storage chamber 74. The transmission mechanism case 72 is formed with a boss 76 that protrudes from the middle of the longitudinal direction toward the center of the vehicle width.
The transmission mechanism 75 is a combination structure of a belt-type transmission mechanism 75A connected to the crankshaft 61 and a gear mechanism 75B connected to the belt-type transmission mechanism 75A, and connects the rear wheel axle 77 to the output side of the gear mechanism 75B. In addition, the rear wheel axle 77 is rotatably supported. Reference numeral 78 denotes a cover.

On the other hand, the generator cover 66 has a front arm 81 attached so that it can swing up and down. Specifically, a support shaft 82 is integrally provided at the front portion of the front arm 81, and the support shaft 82 is rotatably supported on the generator cover 66 via a bearing 83.
The front arm 81 extends rearward, and a boss portion 84 projects from the rear end along the rear portion of the crankcase 52 toward the vehicle width center side. The boss portion 76 of the transmission mechanism case 72 is bolted to the boss portion 84 by bolts 85 and 85. It is combined with. Further, the front arm 81 is formed by connecting a rear arm 86 to the rear portion with a bolt 87. The rear arm 86 extends rearward, and a rear wheel axle 77 is rotatably supported at the rear end thereof.

  Such a combination structure of the transmission mechanism case 72 and the front and rear arms 81 and 86 forms a rear fork (swing arm) 88 having a substantially H shape in plan view. Therefore, the front portion of the rear fork 88 that supports the rear wheel 18 via the rear wheel axle 77 can be attached to the crankcase 52 so as to be able to swing up and down.

In the present invention, the center P1 of the crankshaft 61 is made to coincide with the swing center P2 of the rear fork 88, that is, the swing center P2 of the transmission mechanism case 72 and the front arm 81.
If the swing center P2 of the rear fork 88 does not match (offset) with respect to the center P1 of the crankshaft 61, a mechanism for transmitting power from the crankshaft 61 to the rear wheel 18 (transmission mechanism). Is different from the swing angle of the rear fork 88. Therefore, the structure of the transmission mechanism must be complicated.

  On the other hand, in this embodiment, the swing center P2 of the rear fork 88 matches the center P1 of the crankshaft 61. Specifically, the drive pulley 79 of the transmission mechanism 75 is directly connected to the crankshaft 61 so that the input side center of the transmission mechanism 75 and the swing center P2 of the transmission mechanism case 72 are aligned with the center P1 of the crankshaft 61. As a result, the swing angle of the transmission mechanism 75 is the same as the swing angle of the rear fork 88. Therefore, the transmission mechanism 75 (mechanism for transmitting power from the crankshaft 61 to the rear wheel 18) is simplified. The central axis of the drive pulley 79 is arranged in parallel with the crankshaft 61. In the embodiment, the drive pulley 79 is attached to the shaft end of the crankshaft.

  In addition, the above prior art (Japanese Patent Publication No. 1-333392) transmits the power of the crankshaft to the belt type continuously variable transmission via the output shaft, and matches the center of the rear fork to the center of the output shaft. It has been made. However, since this embodiment does not have such an output shaft, the transmission mechanism becomes simpler.

  Further, this figure shows that brackets 89 and 89 for connecting the lower portions of the left and right rear cushion units 19 and 19 are provided at the rear end of the transmission mechanism case 72 and the rear end of the rear arm 86.

  Here, returning to FIG. The cylinder head 55 is formed integrally with an intake port 92 connected to the combustion chamber 56 and provided with an intake valve 91, and an exhaust port 94 connected to the combustion chamber 56 and provided with an exhaust valve 93. When the engine 16 is viewed from the side, the intake port 92 is an upward opening, and the exhaust port 94 is a downward opening.

An inlet pipe 95 connected to the intake port 92 extends rearward of the cylinder head 55, and a throttle valve 96 is connected to the rear end (upstream end). The upstream end of the throttle valve 96 faces rearward. The inlet pipe 95 is provided with a fuel injection device (injector) 97 that injects fuel toward the intake valve 91.
Such a combined structure of the intake port 92, the inlet pipe 95 and the throttle valve 96 forms an intake passage 98. In other words, the intake passage 98 is extended from the upper part of the cylinder 54 to the rear, and the intake port of the intake passage 98 is directed rearward. Then, the intake port of the intake passage 98, that is, the upstream end of the throttle valve 96 was connected to the air cleaner 45 via the air chamber 47 as shown in FIG. Reference numerals 99 and 99 denote camshafts of the valve operating mechanism 64.

By the way, the engine 16 includes an upper mounting bracket 101 disposed above and behind the central axis of the crankshaft 61 and a lower mounting bracket 102 disposed below and forward of the central axis of the crankshaft 61 in the crankcase 52. In addition, a front mounting bracket 103 is provided below the cylinder head 55.
Specifically, the upper mounting bracket 101 is provided above the cylinder 54, and the lower mounting bracket 102 and the front mounting bracket 103 are provided below the cylinder 54.
Therefore, as is apparent from FIG. 2, the brackets 101, 102, and 103 constituting the mounting support portion for mounting and supporting the engine on the vehicle body frame are disposed in front of and behind the crankshaft 61 in a side view.

FIG. 4 is a left side view of the vehicle body frame according to the present invention.
The body frame 11 extends the main pipe 111 rearward and downward from the head pipe 12, and extends the seat rail 112 from the middle of the main pipe 111 to the rear upper side, while from the head pipe 12 downward to the rear lower side of the main pipe 111. The lower pipe 113 is extended, the lower pipe 114 is extended rearward from the lower end of the down pipe 113, the lower end of the main pipe 111 is joined to the lower pipe 114 in the middle of the length, and the upper pipe 115 (standing frame member) is reared from the rear end of the lower pipe 114. This is a double cradle type frame that extends upward and has the rear end of the upper pipe 115 joined to the longitudinal direction of the seat rail 112.

  This figure shows that brackets 116, 116 for connecting the upper parts of the left and right rear cushion units 19, 19 (only the front left side is shown in the figure, the same applies hereinafter) are provided at the rear part of the seat rail 112. By connecting the rear cushion units 19, 19 between the brackets 89, 89 of the rear fork 88 and the brackets 116, 116 of the seat rail 112, the rear fork 88 is connected to the vehicle body frame 11 via the rear cushion units 19, 19. The rear left and right can be suspended.

FIG. 5 is a left side view of the rear portion of the vehicle body frame, the engine, and the power transmission mechanism according to the present invention.
The left and right upper pipes 115, 115 (shown only on the front left side in the figure. The same applies hereinafter) as the standing frame members of the vehicle body frame 11 are substantially orthogonal to the cylinder 54 in a side view, that is, approximately orthogonal to the cylinder axis L1. It is a member to do. The left and right upper pipes 115, 115 are provided with left and right upper brackets 121, 121 at the upper end, a first cross member 122 spanned between the lower ends, and a lower bracket 123 provided on the first cross member 122. is there. On the other hand, the left and right main pipes 111, 111 are configured such that a second cross member 125 is stretched between lower ends, and a front bracket 126 is provided on the second cross member 125.
A line passing through the center P1 of the crankshaft 61 and the center P3 of the rear wheel axle 77 is defined as L2.

FIG. 6 is a plan view of the engine mounting portion according to the present invention, and shows a structure in which the engine 16 is mounted on the vehicle body frame 11 indicated by an imaginary line.
In this figure, as described above, (1) the left and right upper pipes 115, 115 are provided with left and right upper brackets 121, 121, and (2) the first cross member 122 is bridged between the left and right upper pipes 115, 115. A lower bracket 123 is provided on one cross member 122, a pipe-like lower pivot part 124 is provided on the lower bracket 123, and (3) a second cross member 125 is bridged between the left and right main pipes 111, 111, A front bracket 126 is provided on the second cross member 125, and a pipe-like front pivot portion 127 is provided on the front bracket 126.

  In the first mount structure of the engine 16, bush holes 101a, 101a are formed in the left and right upper mounting brackets 101, 101 provided in the crankcase 52, and annular rubber bushes 131, 131 are formed in these bush holes 101a, 101a. And the rubber bushes 131 and 131 and the left and right upper brackets 121 and 121 are collectively stopped by a single pivot shaft 132 extending left and right.

  The second mounting structure of the engine 16 is such that bush holes 102a, 102a are formed in the left and right lower mounting brackets 102, 102 provided in the crankcase 52, and annular rubber bushings 133, 133 are formed in these bush holes 102a, 102a. And the rubber bushes 133 and 133 and the lower pivot portion 124 are collectively stopped by a single pivot shaft 134 extending left and right.

  The third mount structure of the engine 16 has bush holes 103a, 103a formed in the left and right front mounting brackets 103, 103 provided in the cylinder head 55, and an annular rubber bush 135, formed in these bush holes 103a, 103a. 135 is fitted, and the rubber bushes 135 and 135 and the front pivot portion 127 are collectively stopped by a single pivot shaft 136 extending left and right. The presence or absence of the third mount structure of the engine 16 is arbitrary.

The rubber bushings 131, 133, and 135 are vibration absorbing elastic members of the engine 16. The pivot shafts 132, 134, and 136 are bolts and nuts. In the figure, 137... (... indicates a plurality. The same applies hereinafter) is an elastic member for absorbing left and right vibrations of the engine 16, that is, an elastic member for absorbing axial vibration of the crankshaft 16, and 138.
In the present invention, the engine 16 is attached to the vehicle body frame 11 through the rubber bushings 131, 133, 135 (elastic members) that absorb vibrations in the direction perpendicular to the crankshaft 16, that is, rubber-mounted. It is characterized by that.

Here, returning to FIG. The present invention attaches the rubber bush 131 to the upper bracket 121 above the cylinder 54, thereby attaching the rubber bush 131 for the upper mounting bracket 101 to the upper pipe 115 and above the cylinder 54, and the lower bracket below the cylinder 54. The rubber bush 133 for the lower mounting bracket 102 is attached to the upper pipe 115 and lower than the cylinder 54 by attaching the rubber bush 133 to 123.
Further, according to the present invention, the rubber bush 131 for the upper mounting bracket 101 is disposed above the swing center P2 of the rear fork 88, and the rubber bush 133 for the lower mounting bracket 102 is disposed below the swing center P2 of the rear fork 88. It is characterized by.

When the motorcycle 10 is caused to travel, the rear wheel 18 (see FIG. 4) vibrates according to the road surface condition. This vibration is called “running vibration”.
Since the engine 16 is attached to the vehicle body frame 11 via rubber bushes (elastic members) 131, 133, 135, traveling vibrations transmitted from the rear wheel 18 to the engine 16 via the rear fork 88 are treated with the rubber bushings 131, 133, 133. By relaxing at 135, transmission to the body frame 11 can be made difficult. Therefore, the riding comfort of the motorcycle 10 in which the rear fork 88 is swingably attached to the crankcase 52 can be enhanced.

Furthermore, by extending the cylinder 54 forward from the crankcase 52, a space is created above and below the crankcase 52. Using these upper and lower surplus spaces, rubber bushings 131 and 133 are arranged above and below the cylinder 54, respectively, and these rubber bushings 131 and 133 are attached to an upper pipe 115 substantially orthogonal to the cylinder 54 in a side view. . That is, the rubber bushes 131 and 133 are arranged above and below the swing center P2.
Accordingly, it is easy to secure a space for arranging the rubber bushings 131 and 133, and the structure of the vehicle body frame 11 to which the rubber bushings 131 and 133 are attached is simple. Furthermore, a sufficient distance between the upper and lower rubber bushings 131 and 133 can be secured.

  By the way, due to running vibration, a moment acts on the crankcase 52 (cases) of the engine 16 with the upper rubber bush 131 as the center or the lower rubber bush 133 as the center. Due to the moment, the force acting on the upper or lower rubber bushing 131, 133 decreases as the distance between the upper and lower rubber bushings 131, 133 increases.

  As described above, in the present invention, the rubber bushings 131 and 133 are disposed above and below the cylinder 54, respectively. That is, the rubber bushes 131 and 133 are disposed above and below the swing center P2 of the rear fork 88, respectively. Accordingly, the distance between the rubber bushings 131 and 133 can be set larger. As a result, since the force acting on the rubber bushings 131 and 133 is reduced, the vibration absorbability of the rubber bushings 131 and 133 is increased. Therefore, the travel vibration transmitted to the engine 16 is further reduced by the rubber bushes 131 and 133, so that it can be made difficult to be transmitted to the vehicle body frame 11 and the riding comfort can be further enhanced.

  The mounting structure for a motorcycle according to the present invention is suitable for a scooter type motorcycle.

1 is a left side view of a motorcycle according to the present invention. 1 is a left side view of an engine and a power transmission mechanism according to the present invention. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is a left view of the body frame concerning the present invention. It is a left view of the rear part of a body frame concerning the present invention, an engine, and a power transmission mechanism. It is a top view of the engine attachment part which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Scooter type motorcycle, 11 ... Body frame, 15 ... Handle, 16 ... Engine, 18 ... Rear wheel, 22 ... Seat, 33 ... Footrest floor, 52 ... Crankcase, 54 ... Cylinder constituting multi-cylinder engine, 61 ... crankshaft, 75 ... belt-type transmission mechanism, 88 ... rear fork, 101, 102, 103 ... engine mounting support (bracket), 131, 133, 135 ... elastic member for reducing vibration in the direction perpendicular to the crankshaft, 137 ... An elastic member that relieves vibration in the axial direction of the crankshaft.

Claims (6)

In a scooter type motorcycle provided with a footrest for placing a driver's foot between a seat and a handle,
Attach the front of the rear fork that supports the rear wheels to the engine crankcase so that it can swing up and down.
The engine is arranged with the center axis of the crankshaft directed in the vehicle width direction,
The engine is attached to the vehicle body frame via an elastic member, and the elastic member absorbs vibration transmitted in a direction perpendicular to the crankshaft and absorbs vibration in the axial direction of the crankshaft.
An engine mounting structure for a motorcycle characterized by that. 2. The engine mounting structure for a motorcycle according to claim 1, wherein the engine is attached to the vehicle body frame via a plurality of elastic members, and the elastic members are arranged above and below the cylinder axis in a side view. . 3. The motorcycle according to claim 2, wherein the engine is attached to the vehicle body frame via an elastic member at a position separated in the front-rear direction with respect to the vertical position of the engine in addition to the vertical direction of the cylinder axis. Engine mounting structure. In a scooter type motorcycle provided with a footrest for placing a driver's foot between a seat and a handle,
Attach the front of the rear fork that supports the rear wheels to the engine crankcase so that it can swing up and down.
The engine is arranged with the center axis of the crankshaft directed in the vehicle width direction,
In the engine, mounting support portions for attaching the engine to the vehicle body frame are disposed before and after the crankshaft in a side view,
The engine is attached to the vehicle body frame with a fastening member via an elastic member at the attachment support portion, and the elastic member absorbs vibrations in an axial direction and a radial direction of the fastening member.
An engine mounting structure for a motorcycle characterized by that. The body frame is composed of a pair of left and right members, the engine is a parallel multi-cylinder engine and is configured to extend in a substantially horizontal direction when viewed from the side, and an attachment portion of the engine to the body frame is sandwiched between the pair of left and right body frames. The engine mounting structure for a motorcycle according to any one of claims 1 to 4, wherein the engine is fixed to the vehicle body frame. The automatic engine according to any one of claims 1 to 5, wherein the engine includes a belt-type transmission mechanism including a belt and a pulley, and a central axis of the driving pulley is arranged in parallel with the crankshaft. Engine mounting structure for motorcycles.

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