Abstract: An oil pan structure for a four-cycle engine, in which oil stored in an oil pan is sucked up by an oil pump through an oil strainer and in which oil lubrication is performed by supplying the sucked oil again to each of parts of the engine to be lubricated. In this oil pan structure, a bottom portion of the oil pan is formed nearly like a bowl by being swelled to a side, which is opposite to a crankcase, from an attaching peripheral portion, to which a crankcase lower-part is attached, toward a central portion thereof. An oil pan cover covering a part of the bottom portion is separately provided thereon. Oil passages and are formed from the oil pan cover and the bottom portion. An oil introduction opening portion and an oil suction opening portion 82 are formed in the bottom portion.

Abstract: An engine starter mechanism arrangement for snow vehicles, in which a starter mechanism is disposed so as to maintain excellent traveling stability of the snow vehicle. A crankshaft (7) extends through an engine (2) in a transverse direction of a body frame. A rear balancer shaft (62) is disposed in a rear part of the engine at a location rearward of the crankshaft in a manner extending substantially parallel to the crankshaft. A starter motor (65) is disposed in the engine at a location above the rear balancer shaft.

Abstract: In a snowmobile, a four-cycle engine is mounted in such a manner that its crankshaft is arranged along the body width direction and the central axis of a cylinder(s) is tilted rearward by angle ? with respect to the vertical direction of the body, forming a rear tilted engine. At least part of the engine intake system including an air cleaner box and throttle body, connected to the intake port(s) of the engine is accommodated in the space inside the topmost projected portion of the engine hood. Exhaust is led out to the muffler located in front of the cylinder(s) by the exhaust system connected to the exhaust port(s) at the front of the cylinder head. Further, the intake passage is arranged between the engine body and the steering post.

Abstract: A lubricating structure for engines, wherein an oil feed pump and an oil recovery pump are disposed so as to avoid interference between the oil feed and recovery pumps and a clutch mechanism and an increase in the size of the engine. The clutch mechanism 38 is disposed at a location toward a left end of a crankshaft 7 as an output shaft 7a, which is rotatably supported between an upper crankcase 5 and a lower crankcase 6, that is, disposed on a left side of an engine room. A magnet cover 60 is fixed to right side parts of the two crankcases 5, 6. A magnet MG is disposed between the two crankcases 5, 6 and the magnet cover 60 at a location toward a right end 7b of the crankshaft 7. An oil pump FEP for feeding lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60, and an oil pump SCP for recovering lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60.

Abstract: A four-stroke-cycle engine of a vehicle such as snowmobile comprises a crank case, which is dividable into a plurality of crank case components having mating surfaces, through which the crank case is assembled, a crank shaft rotatably supported in the crank case at a portion between the mating surfaces of the crank case components, and a belt driven-type continuously variable transmission mechanism operatively connected to one end of the crank shaft through a clutch belt. The continuously variable transmission mechanism includes a drive shaft, and the clutch belt is stretched around the drive shaft and the crank shaft so that a tensioning direction of the clutch belt is shifted from a line passing the mating surfaces of the crank case components at a predetermined angle therebetween.

Abstract: A snowmobile provided with a water-cooling type engine has a body, half of which is covered by an engine hood so as to form an engine room therein. The water-cooling engine is transversely mounted in the engine room, and the engine includes a crank case, a cylinder block disposed above the crank case, a cylinder head disposed above the cylinder block, and a crank shaft rotatably supported in a manner inclined rearward. The cylinder head is covered by a head cover so that a mating surface thereof is inclined forward such that a front side of the cylinder head is lower, in level, than a rear side thereof.

Abstract: In a drive mechanism for a four-cycle engine having an output shaft for outputting the torque of the engine by decelerating the rotation of the crankshaft, the output shaft is placed coaxially with the crankshaft. Intermediate shaft having a driven gear for decelerating the rotation of the crankshaft is placed in parallel with the crankshaft. The rotation of the crankshaft is transmitted to the output shaft through the intermediate shaft.

Abstract: In a drive mechanism for a four-cycle engine having an output shaft for outputting the torque of the engine by decelerating the rotation of the crankshaft, the output shaft is placed coaxially with the crankshaft. Intermediate shaft having a driven gear for decelerating the rotation of the crankshaft is placed in parallel with the crankshaft. The rotation of the crankshaft is transmitted to the output shaft through the intermediate shaft.

Abstract: In a snowmobile, a four-cycle engine has an alternator as a generator while the snowmobile body has heat exchangers through which the cooling water of the engine is cooled by heat exchange with external air and snow, in a front part and at the ceiling of a crawler house. The alternator is positioned between the four-cycle engine and the front heat exchanger. Further, an exhaust manifold is arranged at an upper position in front of the engine body while an approximately cylindrical oil filter is provided under the exhaust manifold and inclined forwards in the vehicle's direction of travel.

Abstract: A drive mechanism for a snow vehicle, i.e., so-called snowmobile, includes: a four cycle engine having a cylinder head at the top thereof, arranged at the approximate center of an engine room formed in the front body of the snow vehicle; a steering post having a pair of steering bars for maneuvering the snow vehicle attached at the top end thereof, projectively arranged in the rear of the engine with respect to the vehicle's direction of travel in the engine room, with the steering side slightly inclined to the rear. In this snowmobile, a speed reducing mechanism for reducing the output speed of rotation from the engine is provided in front of the engine with respect to the vehicle's direction of travel.

Abstract: A four-stroke-cycle engine of a vehicle such as snowmobile comprises a crank case, which is dividable into a plurality of crank case components having mating surfaces, through which the crank case is assembled, a crank shaft rotatably supported in the crank case at a portion between the mating surfaces of the crank case components, and a belt driven-type continuously variable transmission mechanism operatively connected to one end of the crank shaft through a clutch belt. The continuously variable transmission mechanism includes a drive shaft, and the clutch belt is stretched around the drive shaft and the crank shaft so that a tensioning direction of the clutch belt is shifted from a line passing the mating surfaces of the crank case components at a predetermined angle therebetween.

Abstract: An engine starter mechanism arrangement for snow vehicles, in which a starter mechanism is disposed so as to maintain excellent traveling stability of the snow vehicle. A crankshaft (7) extends through an engine (2) in a transverse direction of a body frame. A rear balancer shaft (62) is disposed in a rear part of the engine at a location rearward of the crankshaft in a manner extending substantially parallel to the crankshaft. A starter motor (65) is disposed in the engine at a location above the rear balancer shaft.

Abstract: A lubricating structure for engines, wherein an oil feed pump and an oil recovery pump are disposed so as to avoid interference between the oil feed and recovery pumps and a clutch mechanism and an increase in the size of the engine. The clutch mechanism 38 is disposed at a location toward a left end of a crankshaft 7 as an output shaft 7a, which is rotatably supported between an upper crankcase 5 and a lower crankcase 6, that is, disposed on a left side of an engine room. A magnet cover 60 is fixed to right side parts of the two crankcases 5, 6. A magnet MG is disposed between the two crankcases 5, 6 and the magnet cover 60 at a location toward a right end 7b of the crankshaft 7. An oil pump FEP for feeding lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60, and an oil pump SCP for recovering lubricating oil is disposed between the two crankcases 5, 6 and the magnet cover 60.

Abstract: A snowmobile provided with a water-cooling type engine has a body, half of which is covered by an engine hood so as to form an engine room therein. The water-cooling engine is transversely mounted in the engine room, and the engine includes a crank case, a cylinder block disposed above the crank case, a cylinder head disposed above the cylinder block, and a crank shaft rotatably supported in a manner inclined rearward. The cylinder head is covered by a head cover so that a mating surface thereof is inclined forward such that a front side of the cylinder head is lower, in level, than a rear side thereof.

Abstract: In a snowmobile, a four-cycle engine is mounted in such a manner that its crankshaft is arranged along the body width direction and the central axis of a cylinder(s) is tilted rearward by angle &agr; with respect to the vertical direction of the body, forming a rear tilted engine. At least part of the engine intake system including an air cleaner box and throttle body, connected to the intake port(s) of the engine is accommodated in the space inside the topmost projected portion of the engine hood. Exhaust is led out to the muffler located in front of the cylinder(s) by the exhaust system connected to the exhaust port(s) at the front of the cylinder head. Further, the intake passage is arranged between the engine body and the steering post.

Abstract: In a snowmobile, a four-cycle engine is mounted in such a manner that its crankshaft is arranged along the body width direction and the central axis of a cylinder(s) is tilted rearward by angle &agr; with respect to the vertical direction of the body, forming a rear tilted engine. At least part of the engine intake system including an air cleaner box and throttle body, connected to the intake port(s) of the engine is accommodated in the space inside the topmost projected portion of the engine hood. Exhaust is led out to the muffler located in front of the cylinder(s) by the exhaust system connected to the exhaust port(s) at the front of the cylinder head. Further, the intake passage is arranged between the engine body and the steering post.

Abstract: An oil pan structure for a four-cycle engine, in which oil stored in an oil pan is sucked up by an oil pump through an oil strainer and in which oil lubrication is performed by supplying the sucked oil again to each of parts of the engine to be lubricated. In this oil pan structure, a bottom portion of the oil pan is formed nearly like a bowl by being swelled to a side, which is opposite to a crankcase, from an attaching peripheral portion, to which a crankcase lower-part is attached, toward a central portion thereof. An oil pan cover covering a part of the bottom portion is separately provided thereon. Oil passages and are formed from the oil pan cover and the bottom portion. An oil introduction opening portion and an oil suction opening portion 82 are formed in the bottom portion.

Abstract: In a cooling arrangement for a water-cooled snowmobile engine, a water pump is disposed on the front side of the cylinder head, under the exhaust manifold and is coupled to a crankshaft so that it is driven by the rotational force which is transmitted through a drive belt from a drive pulley fitted on the crankshaft end. A cooling water inlet port for leading cooling water into the interior of the engine is provided on the front side of the cylinder block and under the exhaust manifold while a cooling water outlet port through which cooling water is taken out from the interior of the engine is arranged on the cylinder head's side face at a position over and opposite to the drive belt and a thermostat is arranged at the cooling water outlet port.

Abstract: A drive mechanism for a snow vehicle, i.e., so-called snowmobile, includes: a four cycle engine having a cylinder head at the top thereof, arranged at the approximate center of an engine room formed in the front body of the snow vehicle; a steering post having a pair of steering bars for maneuvering the snow vehicle attached at the top end thereof, projectively arranged in the rear of the engine with respect to the vehicle's direction of travel in the engine room, with the steering side slightly inclined to the rear. In this snowmobile, a speed reducing mechanism for reducing the output speed of rotation from the engine is provided in front of the engine with respect to the vehicle's direction of travel.

Abstract: In a snowmobile, a four-cycle engine has an alternator as a generator while the snowmobile body has heat exchangers through which the cooling water of the engine is cooled by heat exchange with external air and snow, in a front part and at the ceiling of a crawler house. The alternator is positioned between the four-cycle engine and the front heat exchanger. Further, an exhaust manifold is arranged at an upper position in front of the engine body while an approximately cylindrical oil filter is provided under the exhaust manifold and inclined forwards in the vehicle's direction of travel.