There is no evidence that Robert Crumb filed suit to have his name removed from the film's credits. Contradictory to this claim, Crumb's name continues to appear in the credits, even on home media releases. His name, however, does not appear in the credits for The Nine Lives of Fritz the Cat (1974).
Ralph Bakshi bought the rights to use Billie Holiday's performance of the song "Yesterdays" for $35.
For the Harlem bar scene, Bakshi traveled to Washington Square Park, invited several black militants and activists to the recording studio, and allowed them to say what they wanted. He edited the results to get the dialog heard in the film.
The first animated film to receive an 'X' rating from the MPAA. The X rating was never trademarked by the MPAA and was eventually disavowed in 1990, succeeded by the NC-17 rating. However, since Fritz the Cat was never submitted to the MPAA to be re-rated, it has been unrated since 1990.
Much of the dialogue spoken by incidental characters are actually recordings of real New Yorker's conversations.