The use of prechambers in Otto engines has gained more and more importance in recent years due to the fact that the requirements for reducing emissions from engines are becoming more and more strict. The use of such a combustion space enables the combustion of a lean mixture, the main disadvantages of which are difficult ignition and detonating combustion. In order to reduce these defects, prechambers are installed in the engine head that enable faster ignition of the mixture in the main combustion chamber, thereby reducing peak temperatures, heat losses and emissions of nitrogen oxides NOx. In conventional Otto engines, the use of a normal spark plug does not result in the combustion of a lean mixture, but requires the installation of a prechamber containing an injector (injects a minimum amount of fuel) and a spark plug (ignites a rich mixture). The rest of the fuel is injected directly into the cylinder or into the intake port where it mixes with air and then enters the cylinder. The installation of the prechamber reduces the losses of the exchange of the working substance, and increases the efficiency of the engine due to the possibility of power regulation by controlling the air to fuel ratio. In this paper, various versions of the prechamber are presented, the principle of active and passive prechamber is elaborated, followed by 3D CAD models and related technical documentation. In addition to the model of the prechamber, a 3D CAD model of the chassis of the Yamaha XT 600E motorcycle with an Otto engine was also created, on which each prechamber was upgraded separately.