Abstract: A modified cross-section wire material is formed into piston rings such as oil-control rings for use in an engine. An apparatus of the present invention for forming the modified cross-section wire material has a forming unit (15) comprising in combination a non-powered pre-stage four-roll turks-head (16) and a powered post-staged four-roll turks-head (17). Disposed in tandem and downstream of the forming unit (15) is a non-powered finishing four-roll turks-head (21). A forming roll of the powered turks-head (17) has a diameter equal to or larger than 70 times as much as a height-of a flange of the material. In forming, the material is kept at a tension equal to or less than 300 N between the non-powered turks-head stand (16) and the powered turks-head (17), and at a tension of from 50 to 200 N between the forming unit (15) and the finishing turks-head (21).

Abstract: A modified cross-section wire material is formed into piston rings such as oil-control rings for use in an engine. An apparatus of the present invention for forming the modified cross-section wire material has a forming unit (15) comprising in combination a non-powered pre-stage four-roll turks-head (16) and a powered post-staged four-roll turks-head (17). Disposed in tandem and downstream of the forming unit (15) is a non-powered finishing four-roll turks-head (21). A forming roll of the powered turks-head (17) has a diameter equal to or larger than 70 times as much as a height-of a flange of the material. In forming, the material is kept at a tension equal to or less than 300 N between the non-powered turks-head stand (16) and the powered turks-head (17), and at a tension of from 50 to 200 N between the forming unit (15) and the finishing turks-head (21).

Abstract: The present invention relates to an improvement in an exhaust system structure for a motorcycle. A motorcycle has an engine disposed between front and rear wheels, an exhaust pipe extending from the engine, and a silencer connected to the exhaust pipe for discharging exhaust gases. The silencer, which is a heavy object, is of the type having a gas outlet disposed near a gas inlet. The silencer is disposed below the engine with the gas inlet facing toward the rear wheel, and the exhaust pipe extends to a position near the rear wheel and is connected to the gas inlet of the silencer. By elongating the length of the exhaust pipe and placing the silencer under the engine, the exhaust system performs sufficiently with high output engines, while at the same time lowers the center of gravity of a motorcycle body and balances the weight of the motorcycle body in its longitudinal direction.

Abstract: In a motorcycle, an increase in the wedge effect of the upper cowl occurs with respect to the wind buffeted thereto during travel for reducing wind drag while maintaining continuity of the upper surface of the screen with respect to the upper surface of the head of the rider in a fully bent posture while providing a meter with high visibility even for the rider in a fully bent posture. In a motorcycle wherein the upper surface of the upper cowl covers the upper end portion of the front fork and is formed into a convex surface with a backward rising gradient a screen is provided having an upper surface formed into a convex shape with a backward rising gradient mounted on the upper cowl around the periphery of an open-rear notch for mounting the screen. A meter is disposed inside the upper cowl and the screen.

Abstract: The present invention relates to an improvement in an exhaust system structure for a motorcycle. A motorcycle has an engine disposed between front and rear wheels, an exhaust pipe extending from the engine, and a silencer connected to the exhaust pipe for discharging exhaust gases. The silencer, which is a heavy object, is of the type having a gas outlet disposed near a gas inlet. The silencer is disposed below the engine with the gas inlet facing toward the rear wheel, and the exhaust pipe extends to a position near the rear wheel and is connected to the gas inlet of the silencer. By elongating the length of the exhaust pipe and placing the silencer under the engine, the exhaust system performs sufficiently with high output engines, while at the same time lowers the center of gravity of a motorcycle body and balances the weight of the motorcycle body in its longitudinal direction.