Abstract: A crankcase for a multiple-cylinder four-cycle engine, including an upper crankcase and a lower crankcase which are joined to each other at a joint surface; a separating wall which is integrally cast with the upper crankcase and the lower crankcase to extend from the joint surface toward the opposite side of the joint surface and are configured to define crank chambers corresponding to adjacent cylinders; and a crank journal bearing hole which is formed on the separating wall and is configured to support a crankshaft. At least the separating wall formed in the upper crankcase has a thickness that increases from the joint surface of the crankcase to a region near a deepest portion of the crank journal bearing hole and decreases from the region near the deepest portion of the crank journal bearing hole toward the opposite side of the joint surface of the crankcase.

Abstract: A vehicle combustion engine includes an engine cylinder block having an exhaust port defined in a front surface area thereof and fluidly connected with an exhaust tube. A transmission is arranged rearwardly of a crankcase. The vehicle combustion engine also includes at least one of an oil filter for filtering oil and an oil cooler for cooling the oil, which is positioned outside the cylinder block and the crankcase, but close to a lower portion of the cylinder block at a location rearwardly of the cylinder block.

Abstract: An exhaust system of an engine of a motorcycle, including an exhaust pipe configured to extend in one of an upward direction and a downward direction from an exhaust port formed at a front portion of a cylinder head of the engine and to then be bent to extend in an opposite direction to form a bent portion at a location in front of the engine.

Abstract: A vehicle combustion engine includes an engine cylinder block having an exhaust port defined in a front surface area thereof and fluidly connected with an exhaust tube. A transmission is arranged rearwardly of a crankcase. The vehicle combustion engine also includes at least one of an oil filter for filtering oil and an oil cooler for cooling the oil, which is positioned outside the cylinder block and the crankcase, but close to a lower portion of the cylinder block at a location rearwardly of the cylinder block.

Abstract: A crankcase for a multiple-cylinder four-cycle engine, including an upper crankcase and a lower crankcase which are joined to each other at a joint surface; a separating wall which is integrally cast with the upper crankcase and the lower crankcase to extend from the joint surface toward the opposite side of the joint surface and are configured to define crank chambers corresponding to adjacent cylinders; and a crank journal bearing hole which is formed on the separating wall and is configured to support a crankshaft. At least the separating wall formed in the upper crankcase has a thickness that increases from the joint surface of the crankcase to a region near a deepest portion of the crank journal bearing hole and decreases from the region near the deepest portion of the crank journal bearing hole toward the opposite side of the joint surface of the crankcase.

Abstract: There is provided an in-line multicylinder combustion engine of a type, in which the length and the width of the combustion engine can be reduced; which can be assembled compact in size with its center of gravity lowered in position; in which mass centering in the combustion engine can be accomplished, The engine (E) includes a crankshaft (17), an input shaft (18) and an output shaft (19). The crankshaft (17) is connected with the input shaft (18) through a clutch gear (40). An imaginary plane (H) containing respective axes (70, 80) of the crankshaft (17) and the input shaft (18) lies substantially horizontally, while the axis (90) of the output shaft (19) is positioned above the imaginary plane (H).

Abstract: An exhaust system of an engine of a motorcycle, including an exhaust pipe configured to extend in one of an upward direction and a downward direction from an exhaust port formed at a front portion of a cylinder head of the engine and to then be bent to extend in an opposite direction to form a bent portion at a location in front of the engine.

Abstract: There is provided a lubricating device for a motorcycle combustion engine, which allows the motorcycle to exhibit a desired banking angle and also to have a lower center of gravity. The lubricating device is designed to supply a lubricant oil to an in-line multicylinder combustion engine (E) mounted on a motorcycle frame structure (FR) and having a crankcase (CR) and includes a main gallery (21) formed in a lower portion of the crankcase (CR) and journal oiling passages (25) branched off from the main gallery (21) for supplying the lubricant oil towards crank journals (23b) of a crankshaft (23) of the engine. The main gallery (21) has opposite end portions (21a, 21a) inclined to extend outwardly upwardly.

Abstract: There is provided a lubricating device for a motorcycle combustion engine, which allows the motorcycle to exhibit a desired banking angle and also to have a lower center of gravity. The lubricating device is designed to supply a lubricant oil to an in-line multicylinder combustion engine (E) mounted on a motorcycle frame structure (FR) and having a crankcase (CR) and includes a main gallery (21) formed in a lower portion of the crankcase (CR) and journal oiling passages (25) branched off from the main gallery (21) for supplying the lubricant oil towards crank journals (23b) of a crankshaft (23) of the engine. The main gallery (21) has opposite end portions (21a, 21a) inclined to extend outwardly upwardly.

Abstract: There is provided an in-line multicylinder combustion engine of a type, in which the length and the width of the combustion engine can be reduced; which can be assembled compact in size with its center of gravity lowered in position; in which mass centering in the combustion engine can be accomplished, The engine (E) includes a crankshaft (17), an input shaft (18) and an output shaft (19). The crankshaft (17) is connected with the input shaft (18) through a clutch gear (40). An imaginary plane (H) containing respective axes (70, 80) of the crankshaft (17) and the input shaft (18) lies substantially horizontally, while the axis (90) of the output shaft (19) is positioned above the imaginary plane (H).

Abstract: To provide a combined oil filter and oil cooler unit in which the oil filter and the oil cooler are neatly integrated together to thereby suppress any undesirable interference with peripheral component parts such as, for example, exhaust tubes, the combined oil filter and oil cooler unit (U) includes a mounting bracket (5) adapted to be mounted on a vehicle engine (1) or a vehicle body structure (F) carrying the vehicle engine (1) and having a filter support (5a) and a cooler support (5b) defined therein, an oil filter (3) supported by the filter support (5a) of the mounting bracket (5), and an oil cooler (4) supported by the cooler support (5b) of the mounting bracket (5).