Systems and methods for combustion engines with interchangeable components are described herein. An engine sub-assembly for a gasoline powered engine can include a crankcase having an opening extending at least through an upper surface thereof, the opening being configured to receive a crank arm therethrough, and a first mounting plate configured to be coupled with the crankcase. The first mounting plate can be selectively removable from the crankcase. The opening of the first mounting plate can generally align with the opening in the crankcase when the first mounting plate is coupled with the crankcase. The first mounting plate can be configured to receive a first cylinder block and to couple the first cylinder block to the crankcase. A second mounting plate can be configured to couple with a second cylinder block that is different than the first cylinder block and to couple the second cylinder block to the crankcase.

An engine is described having a crankcase, a liner and a head assembly. The crankcase is split along a plane defining a two part crankcase, where fluid passages are passing through only one of the crankcase portions, so as to not require crossing the split line. A connecting rod also includes a tapered end, and the piston has a complementary carrier receiving the connecting rod.

The overhead camshaft engine (10) includes a cylinder block (11), a crankcase (12) attached to a lower part of the cylinder block to define a crankcase chamber (32), a bearing retaining member (60) attached to a part of the cylinder block, a crankshaft (20) rotatably supported by a pair of bearings (21, 22) supported by the cylinder block and the bearing retaining member, respectively, and a crankshaft pulley (53) attached to a part of the end of the crankshaft projecting outward from the bearing supported by the bearing retaining member.

An engine (E) includes a crankcase body (19) including a bottom plate (19a) and a tubular portion (19c), a crankcase cover (20) covering a case opening portion (19b) of the crankcase body (19), a crankshaft (2), a cylinder base portion (21a) located inside the crankcase body (19), a cylinder block (21b) located outside the crankcase body (19), and a camshaft (25) located inside the crankcase body (19) and between the bottom plate (19a) and cylinder base portion (21a). The crankcase body (19) has the bottom plate (19a) detachably attached to the tubular portion (19c).

An engine (E) includes a crankcase body (19), a crankcase cover (20) covering a case opening portion (19b) of the crankcase body (19), a crankshaft (2), a cylinder base portion 21a located inside the crankcase body (19), a cylinder block (21b) located outside the crankcase body (19). The crankcase cover (20) is detachably attached to an upper portion of the crankcase body (19).

An internal combustion engine-includes at least one cylinder crankcase, at least one cylinder head (2) including at least one valve cover (1), charge-cycle valves, a valve train-assembly, injectors (3), an injector cable harness, injection lines (4), a fuel rail (5) and a pre-separator for separating the oil aerosols present in the blow-by volume flow being situated in the cylinder head (2).

A power unit includes: a crankcase which accommodates a crankshaft and a main shaft arranged in parallel to each other; a crank side cover which covers one end portion of the crankshaft from the outside in an axial direction of the crankshaft; a primary driven gear which is provided in the main shaft and meshes with a primary drive gear of the crankshaft; a clutch provided at one end portion of the main shaft; and a clutch cover which covers the clutch from the outside in an axial direction of the main shaft and is fastened and fixed to a packing surface provided on the crankcase to surround the clutch, wherein the primary driven gear and the packing surface overlap in a virtual straight line when viewed from the axial direction of the main shaft.

An engine is provided with: an engine body; and a top cover that covers the engine body, wherein at least a pair of engaging claws are provided to lateral walls, on both sides, of the top cover so as to extend downward, and a pair of engaging holes with which the engaging claws engage are provided to the engine body side. Each of the engaging claws is provided with a plate section that is provided so as to extend downward, and a bulging section that is provided to the leading end of the plate section and that bulges inward from the plate section, and the bulging section engages with the bottom surface of an inner wall section of the corresponding engaging hole.

An engine (E) includes a crankcase body (19) including a bottom plate (19a) and a tubular portion (19c), a crankcase cover (20) covering a case opening portion (19b) of the crankcase body (19), a crankshaft (2), a cylinder base portion (21a) located inside the crankcase body (19), a cylinder block (21b) located outside the crankcase body (19), and a camshaft (25) located inside the crankcase body (19) and between the bottom plate (19a) and cylinder base portion (21a). The crankcase body (19) has the bottom plate (19a) detachably attached to the tubular portion (19c).

An engine is provided with: an engine body; and a top cover that covers the engine body, wherein at least a pair of engaging claws are provided to lateral walls, on both sides, of the top cover so as to extend downward, and a pair of engaging holes with which the engaging claws engage are provided to the engine body side. Each of the engaging claws is provided with a plate section that is provided so as to extend downward, and a bulging section that is provided to the leading end of the plate section and that bulges inward from the plate section, and the bulging section engages with the bottom surface of an inner wall section of the corresponding engaging hole.