We study the propagation over long distances under the influence of the Raman effect of certain subpicosecond solitons, which are solutions of a perturbed nonlinear Schro¨dinger equation describing the propagation of light pulses in monomode optical fibers. We calculate the corresponding propagation distance limit due to the intrapulse Raman scattering soliton timing jitter. A formula that describes the soliton timing jitter effect due to the influence of amplified spontaneous emission noise on soliton group velocity induced by the coupling between amplitude and velocity is given and the propagation distance limit of soliton communication systems caused by this effect is evaluated.