The Harley, one of four panheads originally purchased by Fonda from an L.A. police department auction, was customized by Fonda, customizer Tex Hall and actor Dan Haggerty who had a brief appearance in Easy Rider but is best known for his role in the TV series "Grizzly Adams." The three did all the chopping, welding, fabricating and painting to produce four bikes for the movie. They made two "Billy Bikes" named for and ridden by the character played by Dennis Hopper and two of the more radically chopped Captain America machines ridden by Fonda. Two of each were built in order to switch back and forth due to the rigors of film production.

They held together quite well during the production except for the Captain America that was trashed in the last scene of the movie. The machines seemed poised to become the property of the actors and producers until thieves broke into a storage garage and took them all except the one trashed Captain America. Since the movie had not yet been released, the bikes, in fact, meant little to the thieves as they were nothing more than customized Harley Panheads. They left the damaged Captain America behind.

After the movie was released, Fonda gave the bike to Dan Haggerty who put it back together. From his Woodland Hills home, Haggerty said he rebuilt the bike as a momento to his work on the film.

A Mecum Auction Company spokesman said Haggerty is willing to part with this film artifact only reluctantly, but also stated that the Mecum Auction in Del Mar, in conjunction with the Goodguys Rod and Custom event, would be a good place to sell the bike due to the tens of thousands of people who will be in attendance and have the opportunity to see an American icon.