Abstract: A cooling structure for an engine in a straddled type vehicle provided with steerable left and right front wheels and an engine positioned at the center in a forth-back direction of a vehicle body is improved in that a cooling fan is disposed in front of the engine and an engine radiator is disposed contiguously to an upper half section of the cooling fan.

Abstract: A side cover structure used in a motorcycle having a motorcycle frame, a fuel tank supported on the motorcycle frame, a driver's seat disposed on the motorcycle frame, and an engine supported on the motorcycle frame below the fuel tank and the driver's seat. The side cover structure includes a side cover member attached laterally to the motorcycle frame below the fuel tank and the driver's seat, the side cover member having at least one opening for permitting air to flow therethrough. With this arrangement, the space defined by the side cover member is effectively ventilated to protect a battery, a reservoir tank for a cooling liquid, and other motorcycle elements or components which may be disposed in the space from being affected by the heat produced by the engine. The side cover member allows the battery and the reservoir tank to be visually checked for liquid levels through the opening.

Abstract: Radiator for a two-wheeled motor vehicle with a lateral V-type crankshaft straddle type engine. The radiator is attached to the front section of the down tubes and comprises an upper section between an upper tank connected to coolant recovery piping and a middle tank, and a pair of lower sections between the middle tank and a pair of lower tanks supplying coolant piping at both sides. One of the lower tanks is lower than the other, with a connecting pipe between them inclined so as to equalize the coolant flow speed.

Abstract: A cooler for a belt type transmission in a power unit for vehicles in which a transmission casing is provided on one side of an engine body, and a belt type transmission composed of a drive pulley connected with the crankshaft of the engine body, a driven pulley connected with an output shaft and an endless transmitting belt engaged between the pulleys is contained in a transmitting chamber in the transmission casing, wherein an air intake passage and a rear air exhaust passage are respectively provided front and rear portions of the transmission casing, an intermediate air exhaust passage is provided in the intermediate between the front portion and the rear portion of the transmission casing, so that the inlet of the intermediate air exhaust passage is opened in the zone that the endless transmitting belt is isolated from the driven pulley at the tension side of the endless transmitting belt in the transmission chamber; and further wherein a suction port is opened in the outer wall of the transmission casin

Abstract: An arrangement of an engine radiator in a straddled type vehicle such as a four-wheel buggy vehicle is improved in that an aperture is formed in the rear wall of each front wheel fender, a first louver is disposed so as to cover the front side of the aperture for achieving a mud-guard function and also introducing running wind flowing along the inner surface of the fender into the aperture, each of engine radiator units which jointly form an engine radiator is supported from a vehicle body frame so as to be positioned behind the first louver as opposed to the aperture, and a second louver is disposed so as to cover the rear side of each engine radiator unit for guiding warm running wind which has passed through the engine radiator unit outwards in the widthwise direction of the vehicle body frame.

Abstract: An oiler cooler surrounding the head pipe of a motorcycle on three side and is fixed thereto. It is positioned vertically between the top bridge and the bottom bridge and laterally between the pair of left and right front fork pipes which are inserted through the top and bottom bridges. Upon turning, the cooler remains stationary relative to the motorcycle main frame.

Abstract: A radiator for a motorcycle having a core with an arcuate front surface. The radiator tanks remain parallel. The radiator is retained by means of a pin and fastener means nonconcentrically arranged to insure proper mounting under heavy load road conditions. The tubes of the core may be arranged in either vertical or horizontal extension and may be arcuate to define the concave front surface of the core. Straight tubes of varying width may also be employed to define the arcuate front surface.

Abstract: An air cleaner system for motorcycles employing the hollow interior of a main frame member. A U-shaped cavity facing forwardly of the motorcycle in the fuel tank allows access to the air cleaner assembly positioned within the main frame member. An inlet opening is provided on the upper surface of the main frame member while outlet openings on the lower surface thereof extend to carburetors. The inlet opening of the main frame member is reinforced and a baffle is positioned between the air filter assembly and the intake passages to the carburetors.

Abstract: A motorcycle includes a frame and a front fork connected to the frame and disposed in opposed relation to the front portion of the frame, and an engine mounted on the frame. A radiator is connectable to a fluid circulating system operatively associated with the engine for cooling a fluid flowing through the circulating system. The radiator includes a generally vertically-disposed body pivotally connected at an upper portion thereof to the front portion of the frame for angular movement between an operative position where the radiator body is disposed adjacent to the front portion of the frame and an inoperative position where the radiator body is away from the front portion. Retaining means is formed on the front portion of the frame and disposed at a level lower than the upper portion of the radiator body, the retaining means being engageable with the radiator body when the radiator body is in its operative position to releaseably hold the radiator body against angular movement.

Abstract: A plurality of heat radiating passages are juxtaposed to each other. A fluid distributing chamber and a fluid collecting chamber are disposed at respective opposite ends of the radiating passages in communication therewith. The heat radiating passages each having a substantially U-shaped configuration and extending in the same directions with each other so that the fluid distributing chamber and the fluid collecting chamber are closely juxtaposed to each other.

Abstract: A motor vehicle with a riding saddle has a frame including a main pipe employed as an air intake passage for supplying air to an air cleaner. The main pipe has an air inlet defined in its front end. An air guide member is disposed on one side of the main pipe for introducing external air into the air inlet, and a radiator for cooling a water-cooled engine is disposed on the other side of the main pipe.

Abstract: A motorcycle comprising an engine, a radiator mounted in front of the engine and a seat cowl mounted on the rear portion of the motorcycle, a guide member extends from the radiator to the seat cowl for guiding air from the rear of the radiator to the seat cowl. In one embodiment of the present invention, the guide member is a guide plate which forms a passage with a chamber cover. The air flow through the passage cools an engine exhaust chamber located in the passage. In an alternate embodiment, the guide member is a Y-shaped guide duct having a main body with an air intake located to the rear of the radiator and branched portions with exhaust ports located at the sides of the seat cowl.

Abstract: A device for cooling both a belt casing of an engine and the engine itself, in which both the inside and the outside of the belt casing are cooled by exterior air which is sucked in by respective fans. The air which cools the outside of the belt casing also is used to cool the rest of the engine, and then exits the engine at a side opposite the side at which the air first was sucked in. As a result, air flow through the engine does not impede rotation of the fans and hence does not hamper the cooling process.

Abstract: A water-cooled engine cooler of the divided type for such vehicles as autobikes, autotricycles, four wheel buggy, etc., is disclosed. The cooler has two radiators for cooling the water-cooled engine, these radiators being inclined with respect to the direction of progress of the vehicle such that their axes extending at right angles to their front intersect with each other at a forward position of the radiator.

Abstract: In a motorcycle engine having front and rear engine blocks arranged along the longitudinal line of a vehicle body, the front engine block is equipped with cooling fins for air-cooling and the rear engine block is provided with a water jacket for water-cooling. The engine may be a V-type engine or a horizontal opposed-type engine. The present invention is applicable to a motor scooter having left and right steps for placement of the feet of the driver to place his feet, the steps being installed in the lower portion of the vehicle body between the front and rear wheels of the vehicle.

Abstract: The present invention discloses a cowling structure of thin sheet material which forms a part of the vehicle frame in which the opposite side sections of the cowling firmly interconnected through the medium of the power propelling unit. Formed in one, or preferably both, of the opposite side sections of the cowling structure is an air outlet opening in which a radiator unit is fitted and a bifurcated air passage duct is defined in the cowling structure by an air-flow dividing guide plate so that an ample air supply is obtained through the front opening of the cowling to the pair of right and left radiator units during vehicle travel. In this manner, a cooling system of highly increased capacity is obtainable without any increase in air resistance of the vehicle. The guide plate also serves to strengthen the cowling structure without any substantial increase in weight.

Abstract: A radiator circular or conical in shape for a motorcycle which may be advantageously located in a position adjacent the motorcycle in an arrangement similar to that of a muffler. The radiator includes a core of ring-shaped cross section with an inlet tank and an outlet tank. The inlet and outlet tanks may be positioned on either end of the radiator with radiator tubes extending generally longitudinally therebetween. Alternately, the tubes may be ring-shaped with the inlet and outlet tanks arranged generally along the longitudinal direction. A plurality of corrugated or plate fins may be used to enhance heat transfer. A plate may be positioned at one end of the radiator to insure radial air flow through the core thereof.

Abstract: An engine cooling system for a small motorcycle employing a radiator mounted compactly in the vacant space in front of a water-cooled engine. The radiator and engine are located and protected in the rear body of the motorcycle. The rear body prevents the radiator from being damaged by objects picked up from the roadway. Outlet openings at the rear of the rear body aid in the flow of air through the radiator, passed the engine and from the engine compartment.

Abstract: Motorcycles having front leg shields, step floors and rear bodies. The rear bodies contain engines and water cooling systems therefor. The radiators of such systems are located above or behind the engine with inlet air directed to the radiator and independently to the engine of these motorcycles.

Abstract: A motorcycle having a radiator mounted forwardly of the fuel tank and above the engine. The motorcycle further includes a cowling extending from forwardly of the radiator to either side of the motorcycle. A radiator baffle plate is positioned between the radiator and the fuel tank. This plate includes a downwardly extending panel which is positioned between the radiator and the fuel tank and which further extends rearwardly on either side of the motorcycle to positions to either side of and adjacent the forward portion of the fuel tank. Passageways are created between the cowling and the downwardly extending panel to direct the air heated by the radiator downwardly and to the side of the motorcycle for discharge without impinging upon the rider.

Abstract: Motorcycles of the type having front leg shields, step floors and rear mounted engines have water-cooled engines with radiators mounted at the front leg shield. Tubes connecting the radiator with the water-cooled engine extend below the step floor. In certain of the embodiments, a trunk is illustrated within which the filler cap and the radiator tank are positioned for easy access. The trunk may be mounted above and spaced from the front fender to define a passage for frontal air to be directed to the front mounted radiator.

Abstract: A motorcycle having a water-cooled engine. The cooling system includes a radiator located in a hollow front leg shield of the motorcycle. The radiator may be positioned on one side of the down tube while a radiator tank is located on the other. A damper mechanism is disclosed which allows selected flow of heated air from the radiator to be directed toward the rider for warmth. Alternately, heated air flows from the radiator downwardly from the hollow interior of the front leg shield.

Abstract: A system for cooling the engine compartment and for providing clean air to the air cleaner of a motorized cycle having a body cover, including an engine fan, a fan cover extending between the fan and a head cover surrounding the cylinder head, and a vent hole in the shroud formed by the fan cover and the head cover directing the air flow induced by the fan, after it has been used to cool the cylinder head, into the engine compartment defined by the body cover and towards the air cleaner intake port.

Abstract: A radiator system for motorcycles including a radiator mounted on the front of the motorcycle frame such that the filler cap affixed to the top of the radiator filler tube is located within a chamber in the front of the motorcycle frame and is enclosed within said chamber by means of a pair of perforated cover plates detachably mounted on each side of the motorcycle frame.

Abstract: A cooling fan is provided on at least one of the drive pulley and the driven pulley which are drivingly coupled together by means of a belt. The casing in which the pulleys and the belt are accommodated is provided with air inlet port means and air outlet port means. Rotation of the cooling fan in unison with rotation of the pulley provided with the cooling fan causes fresh air to be forcibly sucked into the casing through the air inlet port means, and discharged to the outside through the air outlet port means after cooling the pulleys and the belt. The air inlet port means and the air outlet port means are arranged or constructed so as to prevent intrusion of dust, mud, water, etc. into the casing. Further provided are means for enhancing the efficiency of cooling the driven pulley by the fresh air drawn in as well as means for radiating heat generated within the casing through the casing walls.

Abstract: A motorcycle having a liquid-cooled engine with a liquid cooling system. The system includes a radiator, a water jacket about the engine and connecting feed and return lines. The radiator is located in the forward part of the motorcycle while the engine is located in the rear. The cooling lines pass beneath a step floor located intermediate a front leg shield and the rear body of the vehicle. A thermostat is positioned to selectively control flow through the return line while a water pump pumps flow to the engine. A bypass line extends from the uppermost portion of the cooling jacket at the engine to the radiator for extraction of air from the system. A pressure controlled radiator cap provides selective communication with a reserve tank.

Abstract: A heat exchange device for mounting between the front fork and the engine of a motorcycle comprises two vertical coolant outflow tanks on either side of a core area, and a coolant inflow tank located midway between the outflow tanks and connected to the latter. The lower part of the device comprises a series of bent tubes having cooling fins therebetween, to form an inverted U-shaped space which straddles the top of the engine, so as to provide sufficient clearance to accommodate the expansion and contraction strokes of the front fork.

Abstract: A cooling structure for an internal combustion engine, comprises a crankcase for housing an engine crankshaft, a cover defining a cooling chamber between the cover and the crankcase and a transmission case integral with the crankcase. The structure comprises communication passages communicable with the cooling chamber and the transmission case chamber for providing air from the outside through the communication passages to the transmission chamber to suppress the overheating of the transmission unit.

Abstract: The present invention is directed to a V-type multi-cylinder internal combustion engine mounted on the middle portion of a vehicle body having front and rear wheels. The internal combustion engine has a supercharger comprising an exhaust turbine provided in an exhaust passage of the engine and a compressor provided in an intake passage of the engine and arranged to be driven by the turbine. In the present invention, an expansion chamber is interposed in the intake passage so as to be positioned between an outlet opening of the compressor and respective intake pipes extending from respective intake ports of the cylinders of the engine. The expansion chamber is placed in a space defined by a V bank of the engine.

Abstract: A radiator mounting mechanism for a motorcycle provided with a water-cooled engine. A pair of radiators are positioned below a fuel tank and are movably supported to a frame by means of the radiator mounting mechanism. The mechanism includes a guide means for guiding the movement of the radiators, and a fixing means for releasably fix the radiator at a desired position relative to the frame.

Abstract: In a motorcycle equipped with a water-cooled engine, part of the frame, on which the engine is supported, is used as a passage for engine cooling water. The above part of the frame may be formed of a hollow tubular member which can be separated from the frame body. The hollow tubular member may be disjoinably joined to the frame body by coupling means utilizing engagement of a pair of a protuberance and a recess or engagement of a pair of a convex surface and a concave surface.

Abstract: A cooling system for the internal combustion engine of a motorcycle includes a radiator and means defining air passages each having a forwardly facing inlet opening disposed respectively on the opposite sides of the motorcycle's front fork. Each air passage extends rearwardly from the inlet opening to an outlet which opens into a plenum chamber disposed adjacent the radiator. The cross-sectional area of each passage increases gradually between its inlet and outlet ends. An exhaust duct is connected to the plenum chamber and the radiator is disposed between the plenum chamber and the exhaust duct.

Abstract: Several embodiments of water cooled motorcycles incorporating an improved compact arrangement wherein the components do not interfere with each other or the rider's stance. In each embodiment the engine cooling system includes a heat exchanger that is positioned on one side of the frame adjacent the down tube. An exhaust system is incorporated that includes an expansion chamber that is disposed on the opposite side of the down tube and which is connected to the engine by a U-shaped section of sufficient length so as to provide the desired exhaust performance. In some embodiments the cooling capacity is increased by employing multiple radiator sections. In each embodiment the side-to-side balance of the motorcycle is maintained by the positioning and sizing of the components.

Abstract: Power unit apparatus for a motorcycle driven by an internal combustion engine has a split power unit case. The crankshaft and the driving shaft of a reduction gear mechanism are clamped between the upper and lower sections of the power unit case. The driven shaft is located on the lower section. A guide shaft for shifter forks and a shift drum controlling operation of the shifter forks are both located on the upper section above the driving and driven shafts.

Abstract: A front wheel suspension system for motorcycles wherein only one front shock absorber is provided and is arranged adjacent the upper part of the front surface of an upper fork. The shock absorber and at least one link mechanism forming a quadrilateral on the side are connected with each other through a rod functioning as a load transmitting member. The number of shock absorbers is thus reduced, the weight of the suspension system is reduced, the moment of inertia required to rotate the suspension system to the right and left is reduced, and the shock absorber is protected from being adversely affected by mud or the like.

Abstract: A front wheel suspension for a motorcycle including at least one first linkage in the form of a four-bar linkage having an upper fork assembly pivoted to the vehicle frame and a lower fork assembly supporting the front wheel, the upper fork assembly and the lower fork assembly being connected with each other through front and rear arms which are both pivotable, and at least one shock absorber, wherein at least one second linkage is interposed between the first linkage and the shock absorber, the second linkage having an input part pivotably connected to the first linkage and an output part pivotably connected to one of the ends of the shock absorber, the output part being movable by a progressive displacement additional to a displacement of the input part with respect to a direction substantially effective for the shock absorber to exhibit the function thereof.

Abstract: A motorcycle is equipped with a water cooled engine and a radiator for the engine. The radiator is mounted to the front fork of the vehicle. A number (symbol) displaying plate is mounted to the front fork ahead of the radiator. An opening is placed adjacent to the mounting plate, and air guides are placed so that the on coming air is guided to the radiator, preferably as a laminar flow.

Abstract: A motorcycle power train arrangement is disclosed which comprises a liquid cooled engine block and a transmission case, substantially exposed and mounted symmetrically to the longitudinal median plane of the motorcycle, largely filling the space between the front wheel and the rear wheel, and including a liquid coolant radiator mounted in substantially vertical position transversely to the direction of travel, a plurality of parallel cylinders being arranged transversely and a crankshaft longitudinally to the direction of travel, the transmission case being located under and/or behind the engine block, and a valve chamber cover forming a symmetrical outer longitudinal limit of the power train; characterized in that the cylinders are located on one side of the engine block in a single line; in that the crankshaft is located on the other side of the engine block and is spaced from and parallel to the longitudinal median plane; and in that covers for the valve chamber and a crank space form on both sides symmetr

Abstract: An induction system for a fuel injection V-type motorcycle engine has a pair of mixing bodies extending upwardly from the intake ports within the V formed by the cylinders. A surging tank is above the mixing bodies and below the fuel tank. An air intake passage is disposed alongside of the surging tank, and an air flow meter is disposed in the intake passage.

Abstract: A two-wheeled motorcycle includes a shell for enveloping a power unit for driving a rear wheel of the motorcycle and to the front end of which a head pipe is fixed. The shell is composed of an upper shell half constituted at least by a top plate and right and left side plates, and a lower shell half constituted at least by left and right side plates and a bottom plate. The power unit is connected to the lower shell half to serve also as a mechanical strength member. The upper and lower shell halves are separably connected to each other at the ends of the side plates thereof.

Abstract: A motorcycle engine mounting structure having a head tube (23), a main frame pipe (21) extended rearwardly from the head tube, and an engine (60). In order to increase the freedom of design for mounting an engine and to ensure a radiator mounting space, a pair of supporting members (40, 50; 240, 250) are suspended from the front part of the main frame (21), and the engine (60) is supported in the front part through the supporting members.

Abstract: A coolant circulating system for a motorcycle having a liquid cooled engine. The system includes a radiator mounted to the front fork, an engine mounted to the frame, pipes from the engine, pipes from the radiator, and a fluid conducting, two-channel swivel connector on the steering shaft to enable the radiator and engine to be interconnected without requiring flexure of the pipes. Preferably the swivel connector is a body separate from and attachable to the steering shaft.