Complex sentence: Ralston Purina tried further to mature the restaurant's image, renaming it "Monterey Jack's" in 1985, a disastrous move; the Jack in the Box name was restored in 1986.
Split into simpler sentences: Ralston Purina tried further to mature the restaurant's image, renaming it "Monterey Jack's" in 1985, a disastrous move that lasted a short time. The Jack in the Box name was restored in 1986.