Even if the global craze it caused was relatively brief, it was remarkable to witness.
I was a 12-year-old sketching the Captain America chopper on a Mighty Pad at Devon Intermediate, one of millions of boys around the world doing more or less the same thing.
That bike brought more reverie than the moon landing of the same year. Soon after the first movie posters of it appeared in New Plymouth record shops, almost every kid at my school bolted high handlebars on to their bicycles. A few of us even extended our front forks.
Almost overnight, posters of the choppers ridden by Peter Fonda, and a slightly less outlandish one ridden by Dennis Hopper, appeared on teenage bedroom walls across the world.
There hasn't been a motorcycle before or since which affected the popular culture so deeply.
Those heavily chromed forks (extended two feet if they were an inch); ape hangers, upswept exhausts; sissy bar and tear-drop tank emblazoned with the stars and stripes just captivated us.
You didn't have to "like motorcycles", though a lot of us actually did end up doing so.
But why? Despite one of the best soundtracks , it wasn't as if the movie was high art.
A couple of stoners tour the States and get blown away by hillbillies - big deal.
Hopper and Fonda were drunk or stoned through much of the filming. They didn't even write a full script, making up most of the story as they went along. They didn't hire a crew, instead picking up hippies at communes across the country and using friends and passers-by to hold cameras. The movie looked as if it had been made that way, too.
Watch closely and you'll also see what a pig the Captain America bike was to ride. You can see the terror on Fonda's face in some of the riding scenes.
Despite all that, every youngster around at the time adored those bikes.
Today choppers are a relatively arcane art form, pursued by one group of bike enthusiasts. Back then - for a few months anyway - choppers in general, and the Captain America bike in particular, were the meat and drink of teen rebellion.
