We provide infinitely many rational homology 3-spheres with weight-one fundamental groups which do not arise from Dehn surgery on knots in
S
3
S^3
. In contrast with previously known examples, our proofs do not require any gauge theory or Floer homology. Instead, we make use of the
S
U
(
2
)
SU(2)
character variety of the fundamental group, which for these manifolds is particularly simple: they are all
S
U
(
2
)
SU(2)
-cyclic, meaning that every
S
U
(
2
)
SU(2)
representation has cyclic image. Our analysis relies essentially on Gordon-Luecke’s classification of half-integral toroidal surgeries on hyperbolic knots, and other classical 3-manifold topology.