DESC:TECHNICAL FIELD
[0001] The present invention relates generally to an internal combustion engine of a two-wheeled vehicle, and more particularly, but not exclusively, to a holding structure for the internal combustion engine of the two-wheeled vehicle.
BACKGROUND
[0002] An internal combustion engine converts thermal energy obtained from burning of a fuel with an oxidizer (air) into mechanical energy, which can be used to do some kind of mechanical work. It is used in a wide range of applications including providing motive force for movement of a vehicle. The main parts of the engine include a cylinder head, a reciprocating piston on a cylinder block a connecting rod which connects the piston to the reciprocating crankshaft and a crankcase assembly.
[0003] Typically, the crankcase assembly for the internal combustion engine of the two-wheeled vehicle is divided into a left crankcase member and a right crankcase member. Generally, a sprocket and drive chain assembly is fitted to a side wall of the left crankcase member. The sprocket and drive chain assembly includes a sprocket fitted to a drive shaft with an endless drive chain wound around the sprocket.
[0004] Conventionally, the internal combustion engine includes an output shaft that is connected to driven wheel through the sprocket and drive chain assembly. The sprocket and chain assembly is an important force transmitting member that bears extreme load changes resulting into unpleasant gear clash noise during gear shifting operation in a sequential manual transmission gear boxes.
[0005] The existing arrangement of the sprocket and drive chain assembly on the side wall of the crankcase assembly results in unpleasant noise arising due to rubbing of a drive chain against at least one component and at least one strcuture provided on at least some adjoining portion of the sprocket and drive chain assembly. For example, chain jumping and/or whipping action of the drive chain may lead to damage of at least one inner wall and the at least one component including gear position sensor, speed sensor, etc, located in said at least some adjoining portion of the sprocket and drive chain assembly.These unpleasant noises and the damage to said at least one structure and the components may also result in uneven wearing off of the drive sprocket sleeve and the sprocket hub, which may lead to disturbed force transmission from the driven shaft to the rear wheel.
[0006] Hence, it is desirable to provide a guarding mechanism for the internal combustion engine in order to protect said at least one structure and at least one component provided on the side wall of the left crankcase member of the crankcase assembly from the undesirable effects of chain whipping and jumping action of the drive chain.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
[0008] Fig. 1 illustrates a right side view of a two-wheeled vehicle as an example, in accordance with one embodiment of the present invention.
[0009] Fig. 2 illustrates a side view of an engine assembly of the two-wheeled vehicle shown in Fig. 1, in accordance with one embodiment of the present invention.
[00010] Fig. 3 illustrates an enlarged perspective view of a left crankcase member of a crankcase assembly of the two-wheeled vehicle shown in Fig. 1, in accordance with one embodiment of the present invention.
[00011] Fig. 4 illustrates an exploded perspective view of the left crankcase member of the crankcase assembly of the two-wheeled vehicle shown in Fig. 1, in accordance with one embodiment of the present invention.
[00012] Fig. 5 illustrates a perspective view of a holding structure of the two-wheeled vehicle shown in Fig. 1, in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION
[00013] Most conventional two-wheeled vehicle utilizes a sprocket and a drive chain assembly mounted on the vehicle’s transmission output shaft to transmit power from the sprocket to a rear wheel of the vehicle. Generally, the sprocket and drive chain assembly fitted to a side wall of a left crankcase member of a crankcase assembly includes a drive chain wound over the sprocket. When the vehicle is running, the rear wheel of the vehicle can cause the drive chain to be whipped forward by the sprocket with a potential for causing damage to an engine casing. Such whipping action of the drive chain may result in damage to at least one structure including inner walls formed on the side wall of the crankcase assembly and also to at least one component including gear position sensor, speed sensor, etc. positioned therein. The damage to the inner walls and said at least one component provided on the side wall of the left crankcase member of the crankcase assembly may lead to the replacement and repair of the components and the engine casing and hence such replacement can be costly and time consuming.
[00014] Additionally, in order to meet the higher torque requirements, the pitch of the drive chain in the internal combustion engine has to be increased. This also helps in improving the durability of the drive chain. Further, such an increase in the pitch of the drive chain also leads to increase in the size or diameter of the sprocket, which eventually means that the clearance with the surrounding components and with the enclosing crankcase in the layout is largely reduced.
[00015] With the above objectives in view, it is desirable to provide a guarding mechanism for the internal combustion engine for the two-wheeled vehicle, which can prevent any damage to said at least one component and said at least one structure in said at least some adjoining portion of the sprocket and drive chain assembly, caused by the whipping and jumping movement of the drive chain wound over the sprocket. Further, it is a challenge to provide internal combustion engine with higher torque and at the same time ensure adequate clearance between the sprocket and drive chain assembly and said at least one component and said at least one structure in said at least some adjoining portion of the sprocket and drive chain assembly.
[00016] According to one embodiment of the present invention, the two-wheeled vehicle comprises a frame assembly extending along a vehicle longitudinal axis and an engine assembly supported by the frame assembly. In one embodiment, said engine assembly includes the crankcase assembly divided into two crankcase members, the sprocket and drive chain assembly including a chain guide structure for guiding the drive chain wound around the sprocket and supported on the side wall of at least one of the two crankcase members of the crankcase assembly. Referring to one embodiment of the present invention, said engine assembly further includes a holding structure being detachably secured to at least a portion of the side wall of at least one of the two crankcase members. In one embodiment, the holding structure comprises one or more retainer wall members protruding radially and extending axially around a periphery of the sprocket and drive chain assembly in the manner so as to form a barricade between the sprocket and drive chain assembly and at least some adjoining portion of the sprocket and drive chain assembly.
[00017] According to one embodiment of the present invention, said at least some adjoining portion of the sprocket and drive chain assembly includes said at least one component positioned on at least a portion of the side wall of said at least one crankcase member and at least one structure formed on said at least a portion of the side wall of said at least one crankcase member. As per one embodiment of the present invention, said at least one component includes speed sensor, gear position sensor etc. positioned on said at least a portion of the side wall of said at least one of the two crankcase members of the crankcase assembly and said at least one structure includes said inner walls formed on said at least a portion of the side wall of said at least one of the two crankcase members of the crankcase assembly.
[00018] The present invention describes the holding structure being detachably mounted around a circumference of a drive shaft. In one embodiment, the holding structure enables enclosing an oil seal and ensures the oil seal remains in position. Further, the holding structure of the present invention enables holding the speed sensor in its position. In one embodiment, the holding structure is jointly mounted on said at least a portion of the side wall of said at least one of the two crankcase members along with the speed sensor. Further, in one embodiment, the holding structure has protruding wall surfaces bisecting the inner surface of the crankcase and the rotating drive chain. Thus, the holding structure ensures that the rotating drive chain do not damage said at least one structure formed on the side wall of said at least one of two crankcase members by rubbing against the crankcase inner surface. In one embodiment, the protruding wall surfaces of the holding structure also ensures that the crankcase is not affected due to jumping or whipping of the rotating drive chain.
[00019] Further, in one embodiment, the holding structure comprises said one or more retainer wall member protruding radially and extending axially around a periphery of the sprocket and drive chain assembly in the manner so as to form a barricade between the sprocket and drive chain assembly and said at least some adjoining portion of the sprocket and drive chain assembly. In one embodiment, said one or more retainer wall members includes a first retainer wall member and a second retainer wall member. The first retainer wall member is integrally formed with the second retainer wall member and protrudes radially from at least a portion of said second retainer wall member. In one embodiment, said at least one component includes a speed sensor, a gear position sensor etc.
[00020] According to one embodiment of the present invention, the holding structure with said second retainer wall member acts as a barricade between the sprocket and drive chain assembly and the gear position sensor positioned in said at least some adjoining portion of the sprocket and drive chain assembly and thereby ensuring that the gear position sensor is not affected due to the rotating drive chain. In one embodiment, the present invention provides the holding structure that can be quickly and easily assembled during assembly of the internal combustion engine, and easily disassembled during servicing of the internal combustion engine.
[00021] The present invention provides the holding structure acting as the guarding mechanism for protecting the adjoining components, the speed sensor, and the gear position sensor mounted on said at least a portion of the side wall of at least one of the two crankcase memebers of the crankcase assembly. The holding structure of the present invention protects and guards said at least one structure formed on said at least some adjoining portion of the sprocket and drive chain assembly against drive chain rubbing.
[00022] In one embodiment, the holding structure of the present invention is a detachable structure that has eliminated several numbers of parts that otherwise would have been required in the internal combustion engine assembly. The holding structure of the present invention also reduced the number of fastening elements which otherwise would have to be used.
[00023] Further, in one embodiment, the holding structure of the present invention ensures that the crankcase is not modified to increase the layout clearance with the drive chain. The holding structure also ensures that the size of the sprocket is not reduced due to gear ratio requirements.
[00024] The holding structure of the present invention is assembled behind the sprocket, thereby ensuring non-removal of the holding structure whenever the drive chain or the sprocket has to be serviced. Thus, the holding structure of the present invention ensures that the overall service time is not increased.
[00025] The holding structure of the present invention also helps in achieving other benefits such as reduction in machining operation of the crankcase and other parts in the vicinity of the holding structure. It also reduces the overall machining and assembly cost. The holding structure also helps in reducing the lead time required in the assembly and servicing processes. Moreover, the holding structure of the present invention also ensures that drive chain with enhanced pitch, for example, in one embodiment, the pitch of the drive chain is enhanced from approximately ½” to approximately 5/8”. Further, the holding structure also enhances the overall durability of the engine without any major changes in the layout and other surrounding parts.
[00026] It is an object of the present invention to provide the holding structure in the form of a guarding mechanism for the internal combustion engine, which can be readily and economically removed and repaired or replaced compared to the time and expense involved in repairing or replacing a damaged engine casing.
[00027] Various other features and advantages of the invention are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. With reference to the accompanying drawings, wherein the same reference numerals will be used to identify the same or similar elements throughout the several views. It should be noted that the drawings should be viewed in the direction of orientation of the reference numerals.
[00028] Further, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers to a side to side, or left to right axis relative to the vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
[00029] Fig. 1 illustrates a right side view of a two-wheeled vehicle (100) (hereinafter ‘vehicle’) as an example, in accordance with one embodiment of the present invention. The vehicle (100) has a frame assembly (105), which acts as skeleton for the vehicle (100). The frame assembly (105) extends along a vehicle longitudinal axis (AA) and includes a head tube (105A), a main tube (not shown), and a down tube (not shown). A swing arm (110) is swingably connected to the frame assembly (105). A rear wheel (115) is rotatably supported by the swing arm (110). One or more rear suspension(s) (not shown) is connecting the swing arm (110) to the frame assembly (105) at an angle, to sustain both the radial and axial forces occurring due to wheel reaction, to the frame assembly (105). A seat assembly (125) is mounted to a pair of rear tubes of the one or more rear tubes (not shown), which extend rearwardly from the main tube (not shown). A fuel tank (130) is disposed forwardly of the seat assembly (125).
[00030] Further in Fig. 1, as per one embodiment of the present invention, an engine assembly (135) is mounted to an anterior portion of the frame assembly (105). The engine assembly (135) includes a starting mechanism, a transmission system for transferring the power to the rear wheel (115). Further, the engine assembly (135) includes an intake manifold and an exhaust manifold, and an air supply mechanism is coupled to the intake manifold of the IC engine through a carburetor or the like. A handle bar assembly (140) is connected to a steering shaft (not shown), one or more front forks (145) are coupled to the steering shaft. A front wheel (150) is rotatably supported by the one or more front fork(s) (145). A front fender (155) covers at least a portion of the front wheel (150). The handle bar assembly (140) includes a handle bar, an instrument cluster, handle grips and one or more levers. The vehicle (100) has various electrical loads including a headlamp (160), a tail lamp (175), and a starter motor (not shown). Plurality of body panels (165) are mounted to the frame assembly (105). Further, the vehicle (100) includes an airflow control device, for example in this particular embodiment; a carburetor (170) is used. The airflow control device includes a carburetor, a fuel injector system or the like.
[00031] Fig. 2 illustrates a side view of the engine assembly (135) of the vehicle (100) shown in Fig. 1, in accordance with one embodiment of the present invention. In one embodiment, the engine assembly (135) is composed of a power generating mechanism and a power transmission mechanism integrated with each other. In one embodiment, the engine assembly (135) includes a crankcase assembly (300) (shown in Fig. 3) for housing a crankshaft, a cylinder block (204) mounted to the crankcase assembly (300), and a cylinder head (202) mounted on top of the cylinder block (204). A cylinder head-cover is mounted to the cylinder head (202) that is having a valve train (not shown). The cylinder head-cover, the cylinder head (202) and, the cylinder block (204) are secured to the crankcase assembly (300) through a plurality of fastening members. Further, the engine assembly (135) includes a spark plug (not shown) mounted to cylinder head (202). Furthermore, the present embodiment includes a carburetor (170) (not shown) connected to an intake port of the cylinder head (202), which is disposed in a rear portion of the cylinder head (202). An exhaust port of the engine assembly (135) is coupled to an exhaust assembly (not shown) and being disposed in a front portion of the cylinder head (202).
[00032] Further in Fig.2, as per one embodiment of the present invention, the crankcase assembly (300) (shown in Fig.3) is divided into two crankcase members on both sides in a crankshaft axial direction and As per one embodiment of the present invention, said two crankcase members includes a left crankcase member (212) disposed on left hand side (LH) and a right crankcase member (not shown) disposed adjacently to the crankcase-left member (212) on the right hand side (RH), which are adapted to support engine parts including cylinder block (204), crankshaft, gears, and bearings (not shown). A crank chamber (not shown) and a gear chamber (not shown) are formed in a space formed by coupling together the left crankcase member (212) and the right crankcase member constituting left and right halves of the crankcase assembly (300).
[00033] Referring to one embodiment of the present invention, a left crankcase cover is located at the left crankcase member outside surface (307) comprising a side wall (304), a right crankcase cover located at the right crankcase member outside surface (307) (shown in Fig.3 and Fig.4) comprising a side wall (303) (shown in Fig.3). According to one embodiment of the present invention, said sprocket and drive chain assembly comprising the chain guide structure (219) is mounted within the left crankcase cover attached to the side wall (303) of the outer surface (304) of the left crankcase member (212). As per one embodiment of the present invention, the sprocket and drive chain assembly is mounted about a drive shaft of the engine assembly (135). According to one embodiment of the present invention, the sprocket and drive chain assembly comprises a chain guide structure for guiding a drive chain (208) wound around the sprocket (210) supported on a side wall of at least one of the two crankcase members (212) of the crankcase assembly (300). The sprocket and drive chain assembly ensures that the power from the drive shaft is seamlessly transmitted to the rear wheel (115) (shown in Fig.1) of the vehicle (100). In one embodiment, the sprocket and drive chain assembly includes a sprocket (210) rotatably coupled to the drive shaft of the engine assembly (135). A drive chain (208) is movably disposed around the sprocket (210), in such a manner that the drive chain (208) rotates along with the rotation of the sprocket (210). In one embodiment, a lock plate (206) is mounted about the sprocket (210). According to one embodiment of the present invention, said engine assembly (135) further includes a holding structure (218) being detachably secured to at least a portion of the side wall of at least one of the two crankcase members (212). According to one embodiment of the present invention, the holding structure (218) is disposed substantially behind the sprocket (210) in such a manner that the sprocket (210) and the drive chain (208) can be accessed without removing the holding structure (218). In one embodiment, the holding structure (218) juxtaposes a gear position sensor (216) on one side, and a speed sensor (214) on another side.
[00034] Fig. 3 illustrates an enlarged perspective view of the crankcase assembly (300) of the two-wheeled vehicle (100) shown in Fig. 1, in accordance with one embodiment of the present invention. In one embodiment, the crankcase assembly (300) includes the left crankcase member (212) housing the holding structure (218). In one embodiment of the present invention, the crankcase left member (212) has a crankshaft mounting opening to receive the crankshaft (not shown). As per one embodiment of the present invention, a plurality of roller bearings (302) for mounting the crankshaft is disposed circumferentially around the crankshaft mounting opening.
[00035] As per one embodiment of the present invention, the holding structure (218) includes said one or more retainer wall members (306) protruding radially and extending axially around periphery of the rotating drive chain (208) in the manner so as to form a barricade between the chain guide structure of the sprocket and drive chain assembly (219) and at least some adjoining portion of the sprocket and drive chain assembly (219). Referring to one embodiment of the present invention, said at least some adjoining portion of the sprocket and drive chain assembly (219).includes said at least one component positioned on at least a portion of the side wall (303) of said at least one crankcase member (212) and said at least one structure including said inner walls formed on said at least a portion of the side wall (303) of said at least one crankcase member (212). In one embodiment of the present invention, said at least one component (216) includes a speed sensor, a gear position sensor etc.
[00036] Further in Fig.3, referring to one embodiment of the present invention, said one or more retainer wall members (306) includes the first retainer wall member (306-1) and the second retainer wall member (306-2). In one embodiment, the first retainer wall (306-1) is integrally formed with the second retainer wall member (306-2) and protrudes radially from at least a portion of said second retainer wall member (306-2). Referring to one embodiment of the present invention, the one or more retainer wall members (306) protect the inner surface of the crankcase left member (212) from rubbing against the rotating drive chain (208). Further, the one or more retainer wall members (306) also protect the gear position sensor (216) from coming into contact with the rotating drive chain (208). In one embodiment, the holding structure is jointly mounted with the help of a single fastening element along with the speed sensor (214). Further, in one embodiment, the holding structure (218) guides a speed sensor cable (304) from the speed sensor (214).
[00037] Fig. 4 illustrates an exploded perspective view of the crankcase assembly (300) of the vehicle (100) shown in Fig. 1 in accordance with one embodiment of the present invention, the engine assembly (135) (shown in Fig.2) supported by the frame assembly (105) (shown in Fig.1) includes a crankcase assembly (300) divided into said two crankcase members (212), the sprocket and drive chain assembly (219) including the chain guide structure for guiding the drive chain (208) wound around the sprocket (210) and supported on the side wall (303) of said at least one of the two crankcase members (212) of the crankcase assembly (300). Further, as per one embodiment, the crankcase assembly (300) includes the drive shaft (402) for rotation about a drive axis, a recess in said at least a portion of the side wall (303) for receiving at least a portion of the drive shaft, the oil seal (404) positioned at least in part in said recess and at least partially surrounding said drive shaft (402).
[00038] Further in Fig.4, referring to one embodiment of the present invention, said sprocket (210) of the sprocket and drive chain assembly (219) is rotatably coupled to the drive shaft (402) of the engine assembly (135). In one embodiment, the holding structure (218) is circumferentially disposed about the drive shaft (402) and enables holding an oil seal (404) in position during the rotation of the drive shaft (402). Further, in one embodiment, the holding structure (218) ensures that the speed sensor cable (304) does not interfere with the rotating drive chain (208) by appropriately guiding the speed sensor cable (304).
[00039] Fig. 5 illustrates a perspective view of the holding structure (218) of the vehicle (100) shown in Fig. 1, in accordance with one embodiment of the present invention. In one embodiment, the holding structure (218) acts as a retainer member that retains the oil seal (404) (shown in Fig. 4) in its position during the rotation of the drive shaft (402) (not shown). In one embodiment, the holding structure (218) has a centrally provided drive shaft opening (502) for receiving the drive shaft (402) (shown in Fig.4) and enveloping the oil seal (404) (shown in Fig. 4). In one embodiment, the holding structure (218) includes one or more mounting slots that enables attaching the holding structure (218) with the crankcase left member (212) (shown in Fig.3 and Fig.4).
[00040] In one embodiment, the holding structure (218) includes a top mounting slot (504), and a bottom mounting slot (506). In one embodiment, the bottom mounting slot (506) is a combined mounting slot that jointly mounts the holding structure (218) and the speed sensor (214) (shown in Fig.3 and Fig.4) to the crankcase left member (212). In one embodiment, the holding structure (218) has a protruding cable guide member (508) adjoining the combined mounting slot (506). The cable guide member (508) ensures that the speed sensor cable (304) (shown in Fig.3 and Fig.4) is guided and routed appropriately without interfering with the functioning of the drive chain (208) (shown in Fig.2, Fig.3 and Fig.4). Further, in one embodiment, the holding structure (218) includes the first retainer wall member (306-1) disposed circumferentially and extending axially between the two mounting slots (504), (506). In one embodiment, the first retainer wall member (306-1) protrudes radially in such a manner that it acts as a barricade between the rotating drive chain (208) (shown in Fig.2, Fig.3 and Fig.4) and said at least some adjoining portion of the side wall (303) of the crankcase left member (212), thereby preventing the damage of the crankcase left member (212), which may have occurred due to the rubbing of the rotating drive chain (208).
[00041] Further in Fig.5, referring to one embodiment of the present invention, the holding structure (218) further includes the second retainer wall member (306-2) that is disposed adjacent to the first retainer wall member (306-1). In one embodiment, the second retainer wall member (306-2) extends axially between the top mounting slot (504) and the first retainer wall member (306-1). The second retainer wall member (306-2) also protrudes radially in such a manner that the adjoining gear position sensor (216) (not shown) is isolated from the rotating drive chain (208). The second retainer wall member (306-2) prevents the gear position sensor (216) from rubbing against the rotating drive chain (208).
[00042] Advantageously, as per one embodiment of the present invention, the holding structure with said at least one retainer wall member when detachably secured to said at least a portion of the side wall of said at least one of the two crankcase members, forms a barricade between the sprocket and drive chain assembly and said at least some adjoining portion of the sprocket and drive chain assembly and hence prevents said at least one components positioned in a said at least some adjoining portion of the sprocket and drive chain assembly and said at least one structure formed in said at least some adjoining portion of the sprocket and drive chain assembly from the damage due to the chain jumping and/or whipping movement of the roatating drive chain.
[00043] In addition, as per one embodiment, as the holding strcuture is a detachable strcuture, thus its its assembly and replacement on said at least a portion of the side wall of said at least one of two crankcase members can be done quickly and easily and further can be easily disassembled during servicing of the internal combustion engine.
[00044] Many modifications and variations of the present invention are possible in the light of above disclosure. Therefore, within the scope of claims of the present invention, the present disclosure may be practiced other than as specifically described. ,CLAIMS:I/We claim :
1. A two-wheeled vehicle (100), the vehicle (100) comprising:
a frame assembly (105) extending along a vehicle longitudinal axis (AA);
an engine assembly (135) supported by the frame assembly (105); said engine assembly (135) including a crankcase assembly (300) divided into two crankcase members (212), and a sprocket and drive chain assembly (219) including a chain guide structure for guiding a drive chain (208) wound around a sprocket (210) and supported on a side wall (303) of at least one of the two crankcase members (212) of the crankcase assembly (300);
wherein said engine assembly (135) further includes a holding structure (218) being detachably secured to at least a portion of the side wall (303) of said at least one of the two crankcase members (212); and wherein said holding structure (218) comprises one or more retainer wall members (306) protruding radially and extending axially around a periphery of the sprocket and drive chain assembly (219).
2. The two-wheeled vehicle (100) as claimed in claim 1, wherein said one or more retainer wall member (306) includes a first retainer wall member (306-1) and a second retainer wall member (306-2).
3. The two-wheeled vehicle (100) as claimed in claim 2, wherein said first retainer wall member (306-1) is integrally formed with the second retainer wall member (306-2) and protrudes radially from at least a portion of said second retainer wall member (306-2).
4. The two-wheeled vehicle (100) as claimed in claim 1, wherein said crankcase assembly (300) includes a drive shaft (402) for rotation about a drive axis, a recess in said at least a portion of the side wall (303) for receiving at least a portion of the drive shaft (402), a oil seal (404) positioned at least in part in said recess and at least partially surrounding said drive shaft (402).

5. The two-wheeled vehicle (100) as claimed in claim 3, wherein said second retainer wall member (306-2) of said holding structure (218) comprises of a drive shaft opening (502) and at least one mounting slot.
6. The two-wheeled vehicle (100) as claimed in claim 5, wherein said drive shaft opening (502) is configured for receiving at least a portion of the drive shaft (402) and enveloping the oil seal (404).
7. The two-wheeled vehicle (100) as claimed in claim1, wherein the holding structure (218) comprises said at least one mounting slot including a top mounting slot (504) and a bottom mounting slot (506).
8. The two-wheeled vehicle (100) as claimed in claim 7, wherein the holding structure (218) has a protruding cable guide member (508) adjoining the bottom mounting slot (506).
9. The two-wheeled vehicle (100) as claimed in claim 1, wherein said sprocket (210) of the sprocket and drive chain assembly (219) is rotatably coupled to the drive shaft (402) of the engine assembly (135).
10. The two-wheeled vehicle (100) as claimed in claim 1, wherein said at least one mounting slot is configured to receive one or more fastener for securing said holding structure (218) to said at least a portion of the side wall (300) of said at least one crankcase member (212) of the crankcase assembly (300).