Abstract: A vehicle track includes an endless belt. A plurality of laterally-elongated propulsive lugs and longitudinally-elongated turning lugs extend outwardly from an outer side of the endless belt. The propulsive lugs provide substantially longitudinally facing surfaces that dig into the snow to give the vehicle track propulsion and braking traction. However, the gripping force of the propulsive lugs impedes the longitudinally-elongated track's ability to pivot about a generally vertical axis as the tracked vehicle turns. The turning lugs include longitudinally-elongated side surfaces that substantially face in the lateral direction of the track. When the tracked vehicle is steered, the turning lugs form laterally-facing ramps that push the track upwardly away from the snow in response to lateral forces exerted by the snow on the turning lugs. The resulting upward track movement partially disengages the propulsion and turning lugs from the snow to enhance the track's steerability.

Abstract: A modular family of internal combustion engines is described. The family includes at least three engine configurations selected from a single cylinder, V-type, inline, opposed, W-type, and radial configurations. Each of the engines in the family includes at least one cylinder with identical top end packages. A method for designing such a family of engines is also disclosed. A family of recreational vehicles and method for designing a family of recreational vehicles is also disclosed.

Abstract: A side panel for a recreational vehicle, such as a snowmobile is disclosed. The side panel extends from the windshield portion of the snowmobile to the pan portion. The side panel is hingedly attached at a front edge to the snowmobile so that the side panel opens outwardly along vertically oriented hinges. The side panel includes a windshield to protect the operator's legs. The side panel also includes an airbox which provides an air charge to the engine for combustion. In addition, an airbox, divisible into two parts is also disclosed. The airbox includes a portion adapted to be attached to the interior of the side panel or to a belt guard. A second portion of the air box can be disposed within the engine compartment.

Abstract: A power unit is described that combines an internal combustion engine and a lubrication system. The internal combustion engine includes a crankcase suction chamber and a transmission case suction chamber. At least one partition separates the crankcase suction chamber from the transmission case suction chamber. The lubrication system supplies lubricant to the internal combustion engine. The lubrication system includes a lubrication tank and a supply line for supplying lubricant to the internal combustion engine. At least one crankcase drainage line extends from the crankcase to drain a fluid from the crankcase suction chamber and transfer the fluid to the transmission case suction chamber. At least one pump operatively connects to one of either the crankcase chamber or the transmission case chamber. By the operation of the at least one pump, a negative pressure within at least one of the crankcase chamber and the transmission case chamber is created.

Abstract: A straddle-type vehicle includes a frame supporting front and rear wheels, a seat supported above the frame, and an engine having an output shaft. The engine is supported by the frame below the seat. A transmission is coupled to the output shaft. The transmission includes gears. A shift assembly is operatively connected to the engine and is displaceable over a predetermined distance upon application of a predetermined amount of force by a vehicle operator. The selective displacement of the shift assembly shifts the gears. A parking gear assembly is selectively displaceable along with the shift assembly to selectively engage one of the gears to prevent movement of the output shaft.

Abstract: A front suspension system for a recreational vehicle such as a snowmobile has a lower A-arm assembly and an upper suspension arm for connecting each front ski to the chassis of the recreational vehicle. The lower A-arm restrains the front ski from moving backward or laterally while the upper arm connects to the top of the spindle to ensure that the spindle remains substantially vertical when the front ski encounters a bump.

Abstract: A snowmobile is propelled by an endless track that is operatively connected to the snowmobile's engine by two drive sprockets. Each drive sprocket includes one set of external teeth and two sets of internal teeth that engage three corresponding sets of track teeth formed on the track. Alignment cleats are mounted on the inside of each of one of the sets of track teeth. During low-load operation, contact between the cleats (and the track teeth on which the cleats are mounted) is minimized or eliminated, which reduces or eliminates noise caused by collisions between the metal sprocket and the metal cleats. During higher load operation, the track deforms such that the set of external sprocket teeth engage the cleats and associated set of track teeth.

Abstract: A novel mountain snowmobile comprises a frame, an engine disposed on the frame, at least one ski disposed on the frame, a seat disposed on the frame, a steering device disposed on the frame forward of the seat that is operatively connected to the at least one ski for steering the snowmobile, and a novel long length drive track disposed below the frame and connected operatively to the engine for propulsion of the snowmobile. The novel drive track comprises an endless body having a ground-engaging outer surface with a central portion flanked by first and second lateral portions, a plurality of longitudinally spaced reinforcing rods disposed in the body along a transverse direction of the body. The rods define a plurality of pitches, and a plurality of profiles project from the outer surface of the body along the plurality of pitches. A plurality of non-profile regions is defined along the plurality of pitches, and the profiles and profile-free regions define a pattern for each pitch.