Abstract: An internal combustion engine (10) dry sump lubrication system including multiple oil paths through the engine, the engine being constructed and arranged such that when the engine is mounted on a vehicle and the vehicle is level and upright and the engine is not in operation, oil in each of the multiple oil paths collects at oil collection portions (3,26,514,516) within the engine, each oil collection portion being at a low portion with respect to gravity in one of the oil paths; a plurality of oil drainage openings (510,512,508) fluidly connected to the oil collection portions; and a single drain plug (500) simultaneously removeably sealing each of the oil drainage openings, whereby substantially all of the oil in the system is drained from the system when the single drain plug is removed.

Abstract: An internal combustion engine has a crankcase, a crankshaft, a cylinder block, at least one piston, a cylinder head assembly, and a cooling system for cooling at least a portion of the engine. The cooling system has a first cooling jacket for cooling a first side of the cylinder block, a second cooling jacket for cooling a second side of the cylinder block, and a cylinder head cooling jacket for cooling the cylinder head assembly. A coolant inlet and a coolant outlet fluidly communicate with the first and second cooling jackets respectively. Coolant flowing in the cooling system flows from the coolant inlet to the first cooling jacket, then to the cylinder head cooling jacket, then to the second cooling jacket, and finally to the coolant outlet. A cylinder block, an engine cooling system, and a method of cooling an engine are also disclosed.

Abstract: An internal combustion engine (10) dry sump lubrication system including multiple oil paths through the engine, the engine being constructed and arranged such that when the engine is mounted on a vehicle and the vehicle is level and upright and the engine is not in operation, oil in each of the multiple oil paths collects at oil collection portions (3,26,514,516) within the engine, each oil collection portion being at a low portion with respect to gravity in one of the oil paths; a plurality of oil drainage openings (510,512,508) fluidly connected to the oil collection portions; and a single drain plug (500) simultaneously removeably sealing each of the oil drainage openings, whereby substantially all of the oil in the system is drained from the system when the single drain plug is removed.

Abstract: An internal combustion engine has a crankcase, a crankshaft, a cylinder block, at least one piston, a cylinder head assembly, and a cooling system for cooling at least a portion of the engine. The cooling system has a first cooling jacket for cooling a first side of the cylinder block, a second cooling jacket for cooling a second side of the cylinder block, and a cylinder head cooling jacket for cooling the cylinder head assembly. A coolant inlet and a coolant outlet fluidly communicate with the first and second cooling jackets respectively. Coolant flowing in the cooling system flows from the coolant inlet to the first cooling jacket, then to the cylinder head cooling jacket, then to the second cooling jacket, and finally to the coolant outlet. A cylinder block, an engine cooling system, and a method of cooling an engine are also disclosed.

Abstract: A four cycle engine having at least one cylinder unit is disclosed. The engine includes a continuously variable transmission (CVT) connected to the engine on one side of the engine. An air box is also provided that is located on the same side of the engine as the CVT. The engine further includes an intake manifold operatively connected to the air box for connecting the air box to each cylinder unit and a throttle assembly operatively connected to air box and the intake manifold. The intake manifold may have a generally Y-shaped manifold having a connector leg connected to the throttle assembly and a pair of branches. One branch is operatively connected to one of the cylinder units and another branch is connected to another of the cylinder units. The connector leg is generally parallel to the axis of the crankshaft. The intake manifold may further include a baffle assembly, which directs gas flow within the intake manifold.

Abstract: A snowmobile with arrangement of a four cycle engine is disclosed providing a relatively low center of gravity for improved handling and maneuverability. The engine comprises a cylinder unit slanted to the back of the snowmobile and an improved packaging of auxiliary components in order to optimize the location of the center of gravity on the snowmobile. The engine has a balancer shaft rotatably coupled to the crankshaft and the balancer shaft axis is positioned above the crankshaft axis.

Abstract: A four cycle engine having at least one cylinder unit is disclosed. The engine includes a continuously variable transmission (CVT) connected to the engine on one side of the engine. An air box is also provided that is located on the same side of the engine as the CVT. The engine further includes an intake manifold operatively connected to the air box for connecting the air box to each cylinder unit and a throttle assembly operatively connected to air box and the intake manifold. The intake manifold may have a generally Y-shaped manifold having a connector leg connected to the throttle assembly and a pair of branches. One branch is operatively connected to one of the cylinder units and another branch is connected to another of the cylinder units. The connector leg is generally parallel to the axis of the crankshaft. The intake manifold may further include a baffle assembly, which directs gas flow within the intake manifold.

Abstract: A snowmobile with an arrangement of a four cycle engine is disclosed providing a relatively low center of gravity for improved handling and maneuverability. The engine comprises a cylinder unit slanted to the back of the snowmobile and an improved packaging of auxiliary components in order to optimize the location of the center of gravity on the snowmobile.

Abstract: An arrangement of a four cycle engine is disclosed for use in a vehicle providing a relatively low center of gravity for improved handling and maneuverability. The engine components are located on opposing sides of the longitudinal axis of the vehicle and behind the axis of the crankshaft to move the center of gravity to the middle of the vehicle.

Abstract: A dry sump lubrication system for a four cycle engine is disclosed. The dry sump lubrication system has at least two lubricant storage chambers. A first lubricant storage chamber stores a first volume of lubricant. The first lubricant storage chamber may be located in a lower part of the crankcase. A second lubricant storage chamber is an oil tank and stores a second volume of lubricant. The oil tank may be secured to the output end of the crankcase. The first lubricant storage chamber is capable of storing at least 30% of a total volume of lubricant within the dry sump lubrication system.

Abstract: A torsional-vibration damper for decoupling the torsional vibration between a drive assembly and a secondary assembly is disclosed. The damper includes a first connector operatively connected to one of the assemblies, a pressure body connected to the first connector, a second connector operatively connected to the first connector permitting transmission of rotational motion therebetween, an axial displacement limiter, and a ramp unit. The ramp unit includes a resilient member and a ramp body that is connected to the second connector. The ramp body includes first and second ramps that are operatively interactive with the pressure body. The first and second ramps define a stable position when the first and second ramps and the pressure body are pressed into engagement with one another by the resilient member. The first and second connectors are rotatable with respect to one another through a predetermined angle of rotation measured from the stable position.

Abstract: A vibration and noise dampening connection mechanism for securing at least two components together having a simplified construction is disclosed. A passageway is formed in one of the components with a milled thread having a runout. The end face of the bolt and the runout of the milled thread cooperate to establish an inserted end position having a desired initial tension.

Abstract: An arrangement of a four cycle engine is disclosed for use in a vehicle providing a relatively low center of gravity for improved handling and maneuverability. The engine components are located on opposing sides of the longitudinal axis of the vehicle and behind the axis of the crankshaft to move the center of gravity to the middle of the vehicle.

Abstract: A dry sump lubrication system for a four cycle engine is disclosed. The dry sump lubrication system has at least two lubricant storage chambers. A first lubricant storage chamber stores a first volume of lubricant. The first lubricant storage chamber may be located in a lower part of the crankcase. A second lubricant storage chamber is an oil tank and stores a second volume of lubricant. The oil tank may be secured to the output end of the crankcase. The first lubricant storage chamber is capable of storing at least 30% of a total volume of lubricant within the dry sump lubrication system.

Abstract: A four cycle engine having at least one cylinder unit is disclosed. The engine includes a continuously variable transmission (CVT) connected to the engine on one side of the engine. An air box is also provided that is located on the same side of the engine as the CVT. The engine further includes an intake manifold operatively connected to the air box for connecting the air box to each cylinder unit and a throttle assembly operatively connected to air box and the intake manifold. The intake manifold may have a generally Y-shaped manifold having a connector leg connected to the throttle assembly and a pair of branches. One branch is operatively connected to one of the cylinder units and another branch is connected to another of the cylinder units. The connector leg is generally parallel to the axis of the crankshaft. The intake manifold may further include a baffle assembly, which directs gas flow within the intake manifold.

Abstract: A four stroke internal combustion engine includes a cylinder head having a valve train having reduced profile that permits access to a spark plug assembly located therein.

Abstract: A four stroke internal combustion engine includes a cylinder head having a valve train having reduced profile that permits access to a spark plug assembly located therein.