The real deal with the story

The story was taken from a little known, self published book (in the 80s) called "My Life as a Motorcycle Mama" by Brenda Phillips. Phillips is in the movie as "Bubbles" (the fat broad getting married in the wedding scene).
Phillips was a hanger-on and pretty much wanna-be who got some coin from the screen writer for the story, likeness rights, etc.
It's based on an amalgam of characters from the Arizona biker scene of the 70s; clubs like the Boneshakers and Dirty Dozen.
Some of the stuff is fictionalized, of course; and other events are true, like the guy who rides into the goat-roper bar through the saloon doors, and the ensuing brawl. I know that guy personally.

So anyway, that's the low-down.