During the study of noise emitted by accelerating mini-vehicle control, using theory of sound intensity measurement, it is actualized spotting the noise sources with the mini-vehicle engine. In the procees of the contour of sound intensity and frequency spectrum analysis, main noises of the engine are from oil sump tank and delivery menifold shield and two-way branch exhaust pipe shield. These noises are produced from the engine combustion. According to all analysis, the authors bring forward methods of modifying structure of shield-shell parts and consider them as main methods of reducing noises.