Abstract: A two-cycle internal combustion engine includes a cylinder, a piston in the cylinder and a crankcase pump. The crankcase pump is divided into a first chamber and a second chamber by a membrane. At least one respective transfer passage connects each of the respective chambers to the cylinder. Inlets are provided for admitting pure air into the first chamber and for admitting carbureted air into the second chamber. Devices are provided for opening that one of the transfer passages communicating between the cylinder and the first chamber first and thereafter for opening the one of the transfer passages communicating between said cylinder and said second chamber during operation of the engine.

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.