Abstract: This invention relates to a four-wheeled vehicle intended to be driven as a moped. The vehicle chassis consists of a frame, with four wheels placed in a rhombus pattern. It includes a back drive wheel whose axle is carried by a frame and a front steering wheel whose axle is carried in a fork which is guided in a tube of the frame and which is solid with a handlebar. The steering wheel and fork, like the frame, is centered in relation to the plane of symmetry of the vehicle. The vehicle includes two side stabilizing wheels.

Abstract: A coupling device, located between the drive part and the cycle part of a moped, wherein the crank drive is provided with a stationary double pinion, connected by an endless chain to the free-wheel pinion, which is secured to the back wheel of the moped, for driving the back wheel by either pedaling or by engine power. The axle of the crank drive passes through the hub of a trapezoidically grooved pulley which is connected by an endless belt to the drive pulley, which is driven by an engine. A mechanism, carried by the grooved pulley, makes it possible to optionally connect or disconnect the grooved pulley, and its associated double pinion, from the engine drive. This mechanism constitutes a double lever having a bent projecting nose, which lever is controlled by a pivotable control button to move the lever between a locked and unlocked position, as desired. When the engine drive is uncoupled from the rear wheel of the moped the moped can be powered by pedalling or by free wheeling.

Abstract: An anti-theft device for a vehicle having an internal combustion engine provided with an electrical circuit constituting an ignition or engine-heating circuit. The device includes a first circuit member having an output, a second circuit member having an input, the first and second circuit members being parts of the electrical circuit. A plurality of magnetic switches are disposed in a housing. One or more of the magnetic switches are electrically connected in series between the output of the first circuit member and the input of the second circuit member, all remaining ones of magnetic switches are connected between the input of said second circuit member or the output of the first circuit member and ground of the electrical circuit. One or more magnets are carried on a support in the form of a key which can be inserted into a slot in the housing.

Abstract: A two-cycle internal combustion engine includes a power cylinder, a drive piston being positioned therein. A first transfer duct extends between an auxiliary cylinder, which is supplied with carburetted air and the power cylinder and opens thereinto via a carburetted air inlet port provided on the side wall of the power cylinder or its combustion chamber. A pump crankcase, which is supplied with pure air, is connected to the power cylinder via a second transfer duct which opens thereinto via a scavenging inlet port on the side wall of the power cylinder. An exhaust port is provided on the side wall of the power cylinder. The ports are operatively arranged so that the scavenging port starts to open after the exhaust port and before the carburetted air inlet port.

Abstract: An antitheft device for two-wheeled vehicles includes a U-shaped fork whose central portion is articulated on the vehicle. The two branches pivot about an axis defined by the central portion in planes substantially parallel to the longitudinal plane of symmetry of the vehicle. In a first position, ends of the branches are located near respective sides of a wheel of the vehicle. In a second position the ends are located on sides of a support member. In a third position the ends of the branches are located to the rear of the vehicle. In each of the positions, a locking member, preferably in the form of a bar removably connects the two ends. The locking member includes a key operated lock whose bolt cooperates with an orifice or bore near one end of the U-shaped fork, the orifice or bore acting as a keeper for the bolt.

Abstract: An ignition system for an internal combustion engine, which includes circuitry for producing pulses at a frequency directly related to rotational speed of the engine and a capacitor discharge circuit. A first monostable circuit responsive to the pulses is arranged for triggering the capacitor discharge circuit by passing from its stable state to its unstable state. A second monostable circuit responsive to the pulses is arranged for triggering the capacitor discharge circuit when passing from its unstable state to its stable state. The time constant of the first monostable circuit is substantially equal to the frequency of the ignition system discharge corresponding to the maximum admissible speed of the engine. The time constant of the second monostable circuit being equal to a predetermined value equal to a value of retarded ignition allowing operation of the engine at a reduced power.

Abstract: A security device for a fuel tank of a two-wheeled vehicle having a front fork, which can be locked in a position while it forms an angle other than 180.degree. with respect to the longitudinal plane of symmetry of the vehicle. The device includes a fuel tank cap provided with one or more notches therein. An elongated member, which is fixed on the fork, is so positioned with respect to the cap that when the fork is in its locked position, the member is in one or another of the notches. The result is that when the fork is in the locked position, the fuel tank cap cannot be unscrewed. The notch or notches are formed in the upper surface of the cap and extend to the periphery thereof.

Abstract: A two-cycle internal combustion engine, comprising a first cylinder wherein an engine piston moves and a second cylinder wherein a movable balancing device moves, the internal faces of the engine piston and the movable balancing device delimiting the chamber of a crankcase pump, the outer face of the engine piston delimiting a combustion chamber and the outer face of the movable balancing device delimiting an auxiliary compression chamber.

Abstract: A single-cylinder two-stroke engine having a carburetor, an intake tube leading into the crankcase, and an intake valve between the intake tube and the crankcase has its carburetor flow axis essentially parallel to the crankshaft axis and has the intake valve and the downstream part of the intake tube arranged so that their axis forms an acute angle with the planes perpendicular to the crankcase axis.

Abstract: A transparent plate and a process for the preparation thereof whose transparence at every point is a function of the coordinates of this point. A three-dimensional form representative of said function is made which has a base of a contour homothetic to that of the transparent surface to be made, and the thickness measured from the base is proportional to the values of the function, the form being made from a material which absorbs X-rays. A radiograph of this three-dimensional form is then made on the desired scale, and the transparent plate is the support of the radiograph thus obtained.

Abstract: An anti-theft device for helmets particularly adapted to be used on vehicles with a locking front fork for preventing the vehicle from being stolen. The device contains securing means for securing the helmet to the vehicle and a locking means for locking the securing means by placing the fork of the vehicle in its locked position. The helmet is secured in a position which protects its interior from exposure to the weather.

Abstract: An intake system for an internal combustion engine has been developed to include a translationally movable throttle to cause cross-sectional passage of the intake manifold of the engine cylinders to vary. This throttle utilizes a substantially rigid plate which is pierced with orifices adapted to be connected with each of the intakes corresponding to the various engine cylinders. A movable blade is provided with apertures corresponding in number and spacing to the orifices which contacts with a control and guide means so that the blade is allowed to move parallel to the plate from a running position in which the apertures of the blade are substantially opposite the orifices of the plate to an idle position in which at least the majority of the orifices of the plate are obturated by the blades.

Abstract: A fuel injection assembly has a fuel injector and an air intake manifold connected to a cylinder of an engine. The air intake manifold has an extension which extends between the injector and the cylinder wall to conduct heat coming from the cylinder wall away from the injector and into the air passing through the manifold.

Abstract: A system for separate oil lubrication for internal combustion engines, especially for 2-cycle engines, comprises a tank of oil under pressure and a pump composed of a shaft engaged inside a bore with slight play, at least one of these two elements being threaded and the other being smooth or threaded, these two elements being in relative rotation.