We find the walk-off acceptance for multicolor soliton formation in second-harmonic generation schemes with single-frequency pump light. It is revealed that even though soliton families exist, outside the allowed band of walk-off values they are not actually excited. However, we predict that inside the allowed band the soliton content of the input signals can be almost flat. We also show how the acceptance bandwidth can be adjusted through the mismatch. Direct implications to the experimental observation of temporal quadratic solitons with tilted pulse techniques in phase-matched ß-BaB2O4 and LiIO3 are discussed.