  We perform an $su(2)$ Hamiltonian reduction in the bosonic sector of the
$su(2)$-invariant action for two free $(4,4,0)$ supermultiplets. As a result,
we get the five dimensional \Nf supersymmetric mechanics describing the motion
of an isospin carrying particle interacting with a Yang monopole. Some possible
generalizations of the action to the cases of systems with a more general
bosonic action constructed with the help of the ordinary and twisted \Nf
hypermultiplets are considered.
