Search for the decay [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]]

An upper limit on the branching ratio for the decay [ital K][sup +][r arrow][pi][sup +][nu][bar [nu]] is set at 7.5[times]10[sup [minus]9] (90% C.L.) using the kinematic region above the [ital K][sub [pi]2]([ital K][sup +][r arrow][pi][sup +][pi][sup 0]) peak. When combined with our result from below the [ital K][sub [pi]2] peak, we obtain the limit 5.2[times]10[sup [minus]9]. An upper limit of 1.7[times]10[sup [minus]9] is also found on the branching ratio for decays of the form [ital K][sup +][r arrow][pi][sup +][ital X0] where [ital X][sup 0] is any massless, weakly interacting neutral particle. Limits are also set for cases where [ital M][sub [ital X]][sup 0][gt]0.