The stretch-bender Hamiltonian for a symmetric triatomic molecule, which we have recently derived for a symmetric triatomic molecule [Duxbury et al., J. Chem. Phys. 108, 2336 (1998), preceding paper], has been used in conjunction with the Barrow, Dixon, and Duxbury [Mol. Phys. 27, 1217 (1974)] and the Jungen and Merer [Mel. Phys. 40, 25 (1980)] methods of solving the Renner-Teller coupling problem in molecules which are executing large amplitude nuclear motion, to calculate the vibronic structure of the (a) over tilde (1)A(1) and (b) over tilde B-1(1) states of the methylene radical CH2. The results of the compact stretch-bender variational calculations are compared with the more extensive calculations of Green et al. [J. Chem. Phys. 94, 118 (1991)] to show that good agreement between the two methods has been demonstrated. We have also compared the relative and complementary uses of following the variation of the calculated expectation value of the orbital angular momentum, [L-z], and of the "end over end" rotation constants B and q, as increasingly complex vibronic mixing is caused by the interplay between Renner-Teller and anharmonic coupling. In the present example the anharmonic coupling is principally due to Fermi resonance terms.