Melvin Van Peebles contracted gonorrhea from one of the actresses during filming of one of the sex scenes in the movie. He applied for compensation from the Directors Guild because he "got hurt on the job" and used the money to buy more film.
This was one of Earth, Wind, and Fire's early work. Melvin Van Peebles paid them with a cheque that later bounced. To this day, the band has still not been paid for their contribution to the film.
No Hollywood studio would back this movie with a majority-black cast, so actor/writer/director Melvin Van Peebles financed it himself, aided by a $50,000 loan from Bill Cosby. It became a hit, earning $15 million.
For the biker gang scene, the Hell's Angels were hired, and paid in advance. When the leader of the gang announced that the gang was ready to leave, Peebles refused to let them leave because the scene had not yet been completed. The leader then pulled out a knife and began taunting Peebles. So Peebles "snapped his fingers", and his crew came out with their rifles. The Angels relented and stayed to finish the scene.