Abstract: Disclosed is an oil passageway structure for an engine, which comprises: a body-side oil passage; a cover-side oil passage; an oil passage coupling section in which a first mating face formed around a peripheral edge of an endless transmission band cover-facing open end of the body-side oil passage is coupled to a second mating face formed around a peripheral edge of a body-side oil passage-facing open end of the cover-side oil passage; a groove formed in one of the first mating face and the second mating face; a cutout provided in the one mating face formed with the groove; and a sealing member attached to the groove, wherein the sealing member is formed with an outward protrusion protruding beyond an outer edge-side end of the cutout, and the cutout is formed inclinedly with respect to a cylinder axis as viewed in a cylinder row direction.

Abstract: Disclosed is an oil passageway structure for an engine, which comprises: a body-side oil passage; a cover-side oil passage; an oil passage coupling section in which a first mating face formed around a peripheral edge of an endless transmission band cover-facing open end of the body-side oil passage is coupled to a second mating face formed around a peripheral edge of a body-side oil passage-facing open end of the cover-side oil passage; a groove formed in one of the first mating face and the second mating face; a cutout provided in the one mating face formed with the groove; and a sealing member attached to the groove, wherein the sealing member is formed with an outward protrusion protruding beyond an outer edge-side end of the cutout, and the cutout is formed inclinedly with respect to a cylinder axis as viewed in a cylinder row direction.

Abstract: A four-cycle engine in which a mixed gas of a fuel and air containing a lubricating oil is transferred from a carburetor to a cylinder or a crank chamber, the gas is pushed out in the stage of descending the piston to the passage on the reverse side, transferred into a rocker arm chamber including an intake valve at the top of the cylinder via a passage including a valve gear mechanism, and it is directed to the cylinder in the intake stage, whereby the engine is lubricated by the lubricating oil. The engine has no oil pan and can be run at any inclination angle (360.degree.). Also disclosed is that it is also possible for the four-cycle engine to provide a diverged second passage extending to the crank room, to provide a lead valve on a portion of the second the passage, to provide a diverged third passage extending to the lower end of the crank chamber, to provide a lead valve or rotary valve, and to provide a fourth and/or fifth passage(s) to circulate the mixed gas.