  We discuss the observable effects of enhanced black-hole mass loss in a black
hole--neutron star (BH--NS) binary, due to the presence of a warped extra
spatial dimension of curvature radius $L$ in the braneworld scenario. For some
masses and orbital parameters in the expected ranges the binary components
would outspiral, the opposite of the behavior due to energy loss from
gravitational radiation alone. If the NS is a pulsar, observations of the rate
of change of the orbital period with a precision obtained for the Binary Pulsar
B1913+16 could easily detect the effect of mass loss. For $M_{BH}=7M_\odot$,
$M_{NS}=1.4M_\odot$, eccentricity $e=0.1$, and $L=10\mu$m, the critical orbital
period dividing systems which inspiral from systems which outspiral is
P$\approx$6.5 hours, which is within the range of expected orbital periods;
this value drops to P$\approx$4.2 hours for $M_{BH}=5M_\odot$. Observations of
a BH--pulsar system could set considerably better limits on $L$ in these
braneworld models than could be determined by torsion-balance gravity
experiments in the foreseeable future.
