  Motivated by evidence that the top quark mass lies near the $bWZ$ threshold,
we compute the decay rate for $t\rightarrow bWZ$ in the Standard Model,
including the effects of the finite widths of the $W$ and $Z$ bosons. In the
limit where the width effects are negligible, our results disagree with
previously published calculations. We also examine the decay $t\rightarrow
bWH$. Although the widths induce a sizable enhancement near threshold for both
decays, we find that the rates are still too small to be observed in the
present generation of experiments. This means that detection of either mode in
one of these experiments would be a signal of new physics.
