https://www.wellesnet.com/orson-welles- ... eed-rider/
The British Film Institute lists Rider as a 1974 effort, directed by Sinclair and co-written by Sinclair and Welles. The cast included, Reed, Welles, Kodar and Meg Wynn Owen. It was produced by Brian Jackson.
Relatively little else is known about Rider. The brief filming could have taken place before Welles began shooting the party sequences for The Other Side of the Wind with John Huston and Rich Little in February 1974 or during a break in production in the spring of that year.
It is unknown whether any of the shot footage survives or not.