We build an SU(2)-Hopf bundle over a quantum toric four-sphere whose radius
is non central. The construction is carried out using local methods in terms of
sheaves of Hopf-Galois extensions. The associated instanton bundle is presented
and endowed with a connection with anti-selfdual curvature.Comment: minor changes, appendix section extended. To appear in Letters in
Mathematical Physics. 22 pages, no figure