Abstract: A vibration-absorbing coupler (30A) which is capable of suppressing the torsional vibration of the transmission shaft (7) and also capable of enhancing the durability thereof is disclosed. This vibration-absorbing coupler (30A) is featured in that the rotation of an output shaft (31) of an internal combustion engine (6) is enabled to transmit to a transmission shaft (7) through a torsion coil spring (40A) and torsional vibration of the transmission shaft (7) is enabled to be absorbed by the torsion coil spring (40A). The vibration-absorbing coupler (30A) further includes a regulator (50, 37A) for regulating the rotation of the torsion coil spring (40A) so as not to allow it to twist more than a predetermined angle.

Abstract: A vibration-absorbing coupler (30A) which is capable of suppressing the torsional vibration of the transmission shaft (7) and also capable of enhancing the durability thereof is disclosed. This vibration-absorbing coupler (30A) is featured in that the rotation of an output shaft (31) of an internal combustion engine (6) is enabled to transmit to a transmission shaft (7) through a torsion coil spring (40A) and torsional vibration of the transmission shaft (7) is enabled to be absorbed by the torsion coil spring (40A). The vibration-absorbing coupler (30A) further includes a regulator (50, 37A) for regulating the rotation of the torsion coil spring (40A) so as not to allow it to twist more than a predetermined angle.

Abstract: There are provided a method and an apparatus for applying electroless plating to the cylinder of an internal combustion engine, which are capable of applying the plating exclusively to the portion where the plating is essentially required, thereby making it possible to save the plating solution and to reduce the cost for the metal plating. The plating apparatus is capable of applying electroless plating to the inner surface of the cylinder having a through-hole at the head portion thereof and is constituted by: clamping means for holding the cylinder in a predetermined posture; plating solution-introducing means for introducing a plating solution into the cylinder; and plating solution-circulating means for filling the interior of the cylinder with the plating solution introduced by the plating solution-introducing means while enabling the plating solution to pass along the axial line and through the interior of the cylinder to thereby apply the plating to the inner surface of the cylinder.

Abstract: A method is provided for manufacturing a cylinder for an internal combustion engine, which makes it possible not only to manufacture the cylinder by a high-pressure die casting method at low cost and in high precision, but also to prevent relative misalignment among the scavenging port, suction port and exhaust port of the cylinder. This method is characterized by the steps of: preparing a cylinder liner made of an aluminum alloy pipe and provided with the scavenging port, and a bore-core die as well as cores for scavenging ducts both being uncollapsible and configured so as not to intrude into the scavenging ports; setting the cylinder liner in place in the bore-core die; and casting, by means of metal mold casting method, an aluminum alloy onto the outer peripheral surface of the cylinder liner to thereby mold a main body of the cylinder.