  We have performed detailed numerical calculations of the non-conservative
evolution of close binary systems with low-mass (1.0-2.0 M_sun) donor stars and
a 1.3 M_sun accreting neutron star. Rather than using analytical expressions
for simple polytropes, we calculated the thermal response of the donor star to
mass loss, in order to determine the stability and follow the evolution of the
mass transfer. Tidal spin-orbit interactions and Reimers wind mass-loss were
also taken into account. We have re-calculated the correlation between orbital
period and white dwarf mass in wide binary radio pulsar systems. Furthermore,
we find an anti-correlation between orbital period and neutron star mass under
the assumption of the "isotropic re-emission" model and compare this result
with observations. We conclude that the accretion efficiency of neutron stars
is rather low and that they eject a substantial fraction of the transferred
material even when accreting at a sub-Eddington level. The mass-transfer rate
is a strongly increasing function of initial orbital period and donor star
mass. For relatively close systems with light donors (P < 10 days and M_2 < 1.3
M_sun) the mass-transfer rate is sub-Eddington, whereas it can be highly
super-Eddington by a factor of 10^4 for wide systems with relatively heavy
donor stars (1.6 - 2.0 M_sun) as a result of their deep convective envelopes.
We briefly discuss the evolution of X-ray binaries with donor stars in excess
of 2 M_sun.
  Based on our calculations we present evidence that PSR J1603-7202 evolved
through a phase with unstable mass transfer from a relatively heavy donor star
and therefore is likely to host a CO white dwarf companion.
