  The 1-loop evolution of couplings in the minimal supersymmetric standard
model, extended to include baryon nonconserving $(B\!\!\!/)$ operators through
explicit $R$-parity violation, is considered keeping only $B\!\!\!/$
superpotential terms involving the maximum possible number of third generation
superfields. If all retained Yukawa couplings $Y_i$ are required to remain in
the perturbative domain $(Y_i < 1)$ upto the scale of gauge group unification,
upper bounds ensue on the magnitudes of the $B\!\!\!/$ coupling strengths at
the supersymmetry breaking scale, independent of the model of unification. They
turn out to be similar to the corresponding fixed point values reached from a
wide range of $Y_i$ (including all $Y_i$ greater than unity) at the unification
scale. The coupled evolution of the top and $B\!\!\!/$ Yukawa couplings results
in a reduction of the fixed point value of the former.
