Abstract: A motorcycle has a crankcase containing a crank shaft and a balancer shaft, and a cylinder and a cylinder head positioned above the crankcase, and an exhaust pipe extends from the cylinder head. The balancer shaft is positioned in front of the crank shaft, and the crankcase has a balancer shaft housing supporting the balancer shaft thereinside, and has a recessed part depressed rearward in a front end center part of the balancer shaft housing. The balancer shaft has balancer shaft weights apart from each other in one side and in the other side in an axis direction.

Abstract: One or more throttle bodies and a surge tank are disposed behind a cylinder head, and an intercooler is disposed by being adjacent to the surge tank at a position behind the cylinder head and the one or more throttle bodies. A supercharger is provided in front of the intercooler.

Abstract: A motorcycle has a crankcase containing a crank shaft and a balancer shaft, and a cylinder and a cylinder head positioned above the crankcase, and an exhaust pipe extends from the cylinder head. The balancer shaft is positioned in front of the crank shaft, and the crankcase has a balancer shaft housing supporting the balancer shaft thereinside, and has a recessed part depressed rearward in a front end center part of the balancer shaft housing. The balancer shaft has balancer shaft weights apart from each other in one side and in the other side in an axis direction.

Abstract: One or more throttle bodies and a surge tank are disposed behind a cylinder head, and an intercooler is disposed by being adjacent to the surge tank at a position behind the cylinder head and the one or more throttle bodies. A supercharger is provided in front of the intercooler.

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: 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: An engine controller for a vehicle having an automatic centrifugal clutch device, includes an engine halt controlling means (ECM) for performing engine halt control. The engine halt controlling means halts the engine with the condition that the engine speed becomes equal to or higher than a first set rotational frequency, which is set to be equal to or lower than the clutch engagement rotational frequency of the automatic centrifugal clutch device.

Abstract: A vehicle-mounted four cycle engine control device which includes an oil pressure detecting sensor that detects a pressure of lubricating oil circulated under pressure in an engine. An oil pressure detecting sensor failure judging system judges whether or not the oil pressure detecting sensor has failed. An engine speed judging system judges whether or not a speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system judges whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more.

Abstract: An engine controller for a vehicle having an automatic centrifugal clutch device, includes an engine halt controlling means (ECM) for performing engine halt control. The engine halt controlling means halts the engine with the condition that the engine speed becomes equal to or higher than a first set rotational frequency, which is set to be equal to or lower than the clutch engagement rotational frequency of the automatic centrifugal clutch device.

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: 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 vehicle-mounted four cycle engine control device which includes an oil pressure detecting sensor that detects a pressure of lubricating oil circulated under pressure in an engine. An oil pressure detecting sensor failure judging system judges whether or not the oil pressure detecting sensor has failed. An engine speed judging system judges whether or not a speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system judges whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more.

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: 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: 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.