Abstract: A primary housing for a motorcycle engine includes an inner housing that defines internal coupling apertures, transmission coupling apertures, and external coupling apertures. Internal fasteners extend through the internal coupling apertures and the transmission coupling apertures to couple the inner housing to the crankcase and the transmission. An outer housing defines coupling apertures that align with the external coupling apertures and fasteners extend through the coupling apertures, through the external coupling apertures, and into the engine crankcase to couple the inner and outer housings to the crankcase. A resonant damping device is rigidly or moveably coupled to an anti-node region of the outer housing to reduce noise emissions from the outer housing during engine operation.

Abstract: A primary housing for a motorcycle engine includes an inner housing that defines internal coupling apertures, transmission coupling apertures, and external coupling apertures. Internal fasteners extend through the internal coupling apertures and the transmission coupling apertures to couple the inner housing to the crankcase and the transmission. An outer housing defines coupling apertures that align with the external coupling apertures and fasteners extend through the coupling apertures, through the external coupling apertures, and into the engine crankcase to couple the inner and outer housings to the crankcase. A resonant damping device is rigidly or moveably coupled to an anti-node region of the outer housing to reduce noise emissions from the outer housing during engine operation.

Abstract: A primary housing for a motorcycle engine includes an inner housing that defines internal coupling apertures, transmission coupling apertures, and external coupling apertures. Internal fasteners extend through the internal coupling apertures and the transmission coupling apertures to couple the inner housing to the crankcase and the transmission. An outer housing defines coupling apertures that align with the external coupling apertures and fasteners extend through the coupling apertures, through the external coupling apertures, and into the engine crankcase to couple the inner and outer housings to the crankcase. A resonant damping device is rigidly or moveably coupled to an anti-node region of the outer housing to reduce noise emissions from the outer housing during engine operation.

Abstract: A primary housing for a motorcycle engine includes an inner housing that defines internal coupling apertures, transmission coupling apertures, and external coupling apertures. Internal fasteners extend through the internal coupling apertures and the transmission coupling apertures to couple the inner housing to the crankcase and the transmission. An outer housing defines coupling apertures that align with the external coupling apertures and fasteners extend through the coupling apertures, through the external coupling apertures, and into the engine crankcase to couple the inner and outer housings to the crankcase. A resonant damping device is rigidly or moveably coupled to an anti-node region of the outer housing to reduce noise emissions from the outer housing during engine operation.

Abstract: A breather assembly for a motorcycle engine includes first and second substantially identical rocker supports that are each coupled to a respective cylinder head. Rocker covers are coupled to the rocker supports and cooperate therewith to define respective rocker chambers. Each rocker support defines a first breather passage and a second breather passage. A first breather assembly is coupled to the first breather passage of the first rocker support, and second breather assembly is coupled to the second breather passage of the second rocker support. A gasket member positioned between the rocker supports and the cylinder heads obstructs the unused breather passages of each rocker support. A sealing member is also provided that seals the interface between the rocker support and the rocker cover, and that also seals the interface between the breather assembly and the associated breather passage.

Abstract: A breather assembly for a motorcycle engine includes first and second substantially identical rocker supports that are each coupled to a respective cylinder head. Rocker covers are coupled to the rocker supports and cooperate therewith to define respective rocker chambers. Each rocker support defines a first breather passage and a second breather passage. A first breather assembly is coupled to the first breather passage of the first rocker support, and second breather assembly is coupled to the second breather passage of the second rocker support. A gasket member positioned between the rocker supports and the cylinder heads obstructs the unused breather passages of each rocker support. A sealing member is also provided that seals the interface between the rocker support and the rocker cover, and that also seals the interface between the breather assembly and the associated breather passage.

Abstract: A stamped, steel insert for use in metal die cast articles. The insert includes first and second interconnected stamped steel insert halves spaced from one another at certain locations to define a void. Openings communicating with the void extend through each insert half to facilitate material flow and to improve interlock of the insert and die cast material. The edges of the insert lie below the surface of the casting to avoid bimetallic machining. The insert halves cooperate to define a pair of elongated passages, which are bored following die casting to form fastener holes. At least one of the passages has an elongated cross section to allow for expansion and contraction of the insert during casting.