client.cpp find this:
Code:
void HUD_PostRunCmd

somewhere in body add following
Code:
if (cvar.recoil_switch && me.alive)
        {
                  char signal0[128];
                  sprintf(signal0, "rcl_%s", gGetWeaponName(me.ent->curstate.weaponmodel));
                  extern CommandInterpreter cmd;;
                  cmd.exec(signal0);
        }

Register your cvars
cvar.cpp Code:
REGISTER_CVAR_INT( recoil_switch ,1)

cvar.h Code:
recoil_switch;


rcl_(name of weapon) "(value) recoil" command in your hack main cfg