  Effective \Delta S=1 four fermion operators involving left- and right-handed
currents are relevant in left-right gauge extensions of the standard model and
scalar extension of the Yukawa sector. They induce K to \pi\pi\ decays which
are strictly constrained by experimental data, typically resulting in strong
bounds on the new physics scales or parameters. We evaluate the K to \pi\pi\
hadronic matrix elements of such operators within the phenomenological
framework of the Chiral Quark Model. The results are consistent with the
estimates used in a previous work on TeV scale left-right symmetry, thus
confirming the conclusions obtained there.
