A cutter guard assembly for a knife drive of an agricultural farm implement is provided. The cutter guard assembly includes a cutter bar assembly, a floor assembly and a knife assembly. The cutter bar assembly has a cutter bar. The floor assembly includes a floor extending from the cutter bar and a cover extending from the floor. The knife assembly is covered by and situated below the floor assembly. In operation the cover drapes over a rigid frame of a header shielding the knife assembly from debris.