How bad is it? The lead is unconvincing as himself.
Should you see it? Yes, as a time capsule and for the cast.
Evel Knievel plays himself (George Hamilton played him in a biopic), except that he's now involved in a Hollywood plot. His thrill show is touring Mexico, where criminals plan to sabotage one of his motorcycle jumps, so they can use his coffin to smuggle cocaine. There's some good unintentional laughs. The rest of the cast: Gene Kelly, Lauren Hutton, Red Buttons, Dabney Coleman, Cameron Mitchell and Marjoe Gortner. If that cast intrigues you, you'll like this film.