In this paper we present the results of the analysis of the B-light curve for the flares of the red dwarf YZ CMin , which were observed on September 2002, with the help of the 30-inch Cassegrain telescope of the Stephanion Observatory. The combined use of Fractal analysis, DFT-analysis and Wavelet analysis enable us to estimate the proper random noise and detect possible weak transient optical oscillations. Our results indicate that: (1) Transient high frequency oscillations occur during the flare event and during the quiet-star phase as well. (2) The Observed frequencies range between 0.0083Hz (period 2min) and 0.3 Hz (period 3s) not rigorously bounded. The phenomenon is most pronounced during the flare state. (3) During the flare state:(a) Oscillations with period 2 to 1.5min, 11s, 7.5s and 4s appear during the pre-flare state and persist during the whole flare state, (b) From the flare maximum phase on, a progressive increase of oscillations with periods 20s up to 4.0s is markedly indicated and (c) At the end of the flare only the oscillation of the pre-flare state do remain. This result is in favour of (or does not contradict) the suggested explanation, i.e. the evolution of a fast mode magneto-acoustic wave generated at the impulsive phase of the flare and travelling through the magnetic loop. This procedure may occur many times during the development of a large flare. Finally, the transient optical oscillation, which occurs during the quiet-star state, are not necessary connected with any flare and may be a general characteristic of the active stars atmospheres.