After seeing this film "Knightriders" mentioned on the armourarchive, I figured I'd get a copy and check it out. It appears to be out of print, but copies can still be had for relatively cheap.
The film was made in 1981, and stars Ed Harris. It also has Patricia Tallman, of Babylon-5 fame. Because of when it was made, and presumably had a low budget, it suffers somewhat. It seems to take some of the worst of two decades: the look and feel of the 70's and the cheap production values of the 80's.
I was afraid that it would be some ridiculous "artistic" concept, with Camelot and knights using motorcycles. But it was much, much better. Yes, it features knights riding motorcycles, but they're a band of about 30 people (including mechanics, artists, and musicians) that travels around the country, much like a traveling carnival. They joust with motorcycles, with all of the fanfare of a period tournament.
The story is not complex, and the pacing may seem a bit slow or flat to modern viewers. But the film has a message, about standing up for one's ideals and beliefs. Many of the primary characters are very dynamic, in that they learn important moral lessons, including the main character who learns humility.
The costumes, and even the acting at times, are quite cheezy. The armor and the jousts as portrayed would be quite deadly. The helmets are ridiculous, and the riders all have bare exposed throats as they charge at each other with lances. Even though they show them cutting the lances in advance to weaken them, the inertia of a speeding motorcycle has to go somewhere... and they also use some steel weapons (clearly plastic and fiberglass props though). The various suits of armor used look like they're made out of fiberglass, plastic, and even foam rubber. They also attack the wheels of the bikes to send each other flipping end over end at times.
If you can get past all the cheezy and cheap production values, and just enjoy the story for what it is, you can see elements of an Arthurian tale unfolding. You can also catch a glimpse of knightly chivalry, not just in terms of upholding what's right, but also the combat/tournament mindset, and honor on and off the field.