  We study chargino pair production at LEP II in supersymmetric models with
spontaneously broken R-parity. We perform signal and background analyses,
showing that a large region of the parameter space of these models can be
probed through chargino searches at LEP II. In particular, we determine the
attainable limits on the chargino mass as a function of the magnitude of the
effective bilinear R-parity violation parameter $\epsilon$, demonstrating that
LEP II is able to unravel the existence of charginos with masses almost up to
its kinematical limit even in the case of R-parity violation. This requires the
study of several final state topologies since the usual MSSM chargino signature
is recovered as $\epsilon \to 0$. Moreover, for sufficiently large $\epsilon$
values, for which the chargino decay mode $\chi^\pm \to \tau^\pm J$ dominates,
we find through a dedicated Monte Carlo analysis that the $\chi^\pm$ mass
bounds are again very close to the kinematic limit. Our results establish the
robustness of the chargino mass limit, in the sense that it is basically
model-independent. They also show that LEP II can establish the existence of
spontaneous R-parity violation in a large region of parameter space should
charginos be produced.
