Abstract: The present invention provides a method of operating a dynamic exhaust system of a motorcycle engine. The method includes providing a valve in the exhaust system that is movable to direct exhaust gases between a first flow path through the exhaust system and a second flow path through the exhaust system. The method includes actuating the valve at a first speed to redirect exhaust gases from the first flow path to the second flow path and actuating the valve at a second speed greater than the first speed to redirect exhaust gases from the second flow path to the first flow path.

Abstract: A housing includes a removable cover having a top side and downwardly extending side walls covers a fixed cradle containing an internal combustion engine. The side walls define a plurality of outwardly opening recessed grooves extending from a bottom edge to a plurality of catches. A plurality of stretchable straps are disposed in the recessed grooves with fixed ends attached to the engine cradle and opposite free ends defining tabs that engage the catches to bias the cover to the engine cradle. The cover also defines an air baffle at the top side having a venturi nozzle defined by a convex circumferential surface having a narrowing diameter from top to bottom so that air drawn into engine through the nozzle is essentially non-turbulent. At one end, the cover houses an air filter and has a downwardly extending hold-down to limit movement of the air filter.

Abstract: An intake manifold for a compact internal combustion engine includes a pair of arm having air passageways and coolant passageways formed therethrough. The air passageways couple an air inlet at a carburetor flange to respective air outlets at the ends of the arms. The coolant passageways couple coolant inlets at the ends of arms to a coolant chamber having a first and second coolant outlet, the first coolant outlet providing a first coolant path for connecting the coolant chamber to a radiator assembly, and the second coolant outlet providing a second coolant path for connecting the coolant chamber directly to a coolant pump. A thermostatic valve disposed in the coolant chamber directs the engine coolant along the first and second coolant paths as a function of coolant temperature. The manifold further includes an integral radiator support element.

Abstract: A coolant pump housing for an internal combustion engine includes a cover having integral supports for an ignition module. Each ignition module support projects outwardly to define an elongated member having a mounting end defining a bore sized to receive fasteners for securing an ignition module. Preferably, the coolant pump cover is cast of aluminum. The cover further a pump cavity in fluid communication with inlet and outlet passageways having respective ports for communication of coolant through the coolant pump and the rest of the cooling system.

Abstract: A coolant overflow bottle is interposed between the centrifugal fan and the radiator for guiding air expelled by the fan toward the radiator. The bottle includes a top, a bottom, a pair of nested curved sidewalls, and a rear wall. The side walls are joined at a leading edge, and join the top and bottom. The rear wall is joined to the side walls at a trailing edge, and joins the top and bottom. The bottle wails define an exterior shape for guiding air.

Abstract: A V-type engine having a crankcase with a face, and cylinders arranged so as to form a V space therebetween. Pistons slidably mounted in the cylinders rotatably drive a crankshaft. The crankshaft is rotatably mounted in the crankcase at the junction of the V and has one end extending through the crankcase face. A timing gear engaged by the crankshaft rotatably drives a camshaft rotatably mounted in the crankcase. The camshaft extends through the crankcase face and has a sprocket mounted thereon which engages a drive belt. The drive belt rotatably drives a coolant pump interposed between the crankcase face and flywheel. The coolant pump has a pump cavity which is formed as an integral part of the crankcase face, and an impeller shaft with a rotational axis arranged substantially parallel to the crankshaft outside of the V space. A flywheel is mounted on the crankshaft end extending through the crankcase face and substantially covers the face and coolant pump.