We consider the dimensional reduction of the (deformed) Hermitian YangâMills condition on S1-invariant KĂ€hler Einstein 6-manifolds. This allows us to reformulate the (deformed) Hermitian YangâMills equations in terms of data on the quotient KĂ€hler 4-manifold. In particular, when the gauge group is U(1) we apply this construction to the canonical bundles of CP2 and CP1ĂCP1 endowed with the Calabi ansatz metric to find abelian instantons. We show that these are determined by a suitable subset of the spectrum of the zero section and are explicitly given in terms of certain hypergeometric functions. As a by-product of our investigation we find a coordinate expression for the holomorphic volume form on OCP2(â3) and use it to construct a new special Lagrangian foliation. We also find 1-parameter families of explicit deformed Hermitian YangâMills connections on certain non-compact S1-invariant KĂ€hler Einstein 6-manifolds.