Around the time cosmonauts were orbiting the earth and an unknown band called The Beatles were playing the Top Ten Club in Hamburg, an unusual side project was being cooked up by Honda engineers at Japan's Tama Tech amusement park.
Not much bigger than a tricycle but equipped with a sporty 50cc engine, the prototype Z100 soon became the park's most popular ride, and as people remarked how simian riders looked as they phutted around the track, the novelty bike quickly became known as "the Monkey".
Almost 45 years on, the diminutive Monkey still raises a chuckle from onlookers while providing grown-up bikers with a cool, fun and portable method of short-distance transport. Among those to go ape over them are the pop star Jay Kay and Prince Philip, who rides a Jincheng Easy Rider around the Windsor estate.
Known as "mini" or "pocket" bikes in the US and manufactured also by Yamaha and Harley-Davidson, they are banned in several US cities. With their tiny eight-inch wheels and compact 49cc engines, they are technically not mopeds, which means that bored teens hooked on Jackass-style stunts don't need a licence to ride one. There have already been a number of incidents in the UK, and the Royal Society for the Prevention of Accidents has gone on record with its "concerns about small motorbikes". In its country of origin, meanwhile, the Monkey rivals that of Tamagotchi or Star Wars in terms of cult appeal. At least four magazines reflect the custom Monkey scene in Japan, and to satisfy demand from collectors, Honda bring out an annual limited-edition Monkey.
"The scene is massive in Japan; it's as big as the Mini cult is over here," says David Blackwell of Monkey Bike UK, the main importer of Honda Monkeys and the cheaper Jincheng copies, made in China. His team stages rallies, races and meets all over the country.
Before the weather took a turn for the worse, Blackwell has been selling around 20 bikes a month from his shop in Leamington Spa. Recently, he shipped a two-seater version to Puerto Banus in Spain so that a yacht-owning client could ride around the harbour. Honda publicity from the 1960s featured aircraft captains and gleaming gin palaces, claiming the Monkey was "just the job for storing in your Bentley".
Tom Cole owns a large collection, including a rare tartan-seated 1967 Z50 M. "I can put them into the boot of my van or go on short trips into town," he says. Despite the shortage of power in pre-tuned models, the Monkey rarely goes unnoticed. Adds Cole: "I turned up at the Isle of Man TT race on one and it got more looks than a Ducati."
Blackwell, who offers a basic £200 tuning service right up to a £4,000 Takegawa four-valve, twin-cam engine upgrade, admits that riding a Monkey is not without its dangers.
For a start, riders are lower to the ground than other motorcyclists, so can have problems seeing far ahead. Other vehicles, especially lorries, seem terrifying as they thunder overhead. "Just like other bikers, it's important to wear bright clothing, as well as gloves, boots and full-face motorcycle helmet," advises Blackwell.
Often it's their speed, not size, that poses the danger. Standard versions average only around 30mph, yet with an engine upgrade of up to 120cc, they can reach the heights of 60mph.
To illustrate the mini bike's sporting prowess, Blackwell points to the fast-developing Monkey racing scene, based around the Phoenix Racing Centre, Preston and Scunthorpe's Mini X Motopark. Then there's the annual Isle Wight Monkey Bike Run, where a record 150 devotees turned up this year. Or you can choose the 100-mile cross-country run in the Derby Dales. "There were about 100 of us and we go through all these little villages and up and down the country lanes," he explains. "The views are fantastic, although it can be slow going for those with standard engines." The Monkey magic seems set to continue for a long while yet.
Dan Synge is the author of 'Cool Collectibles' published by Miller's, £14.99
Three classic Honda monkeys
The first Monkey to be imported in the UK. As chic and fashionable as the Lambretta during the 'Swinging Sixties'.
Z50 M (1967)
Improved engine, folding handlebars and higher tartan-covered seat made this the most practical Monkey to date.
Z50 J (1974)
With full front and rear swing arm suspension, this model is still in production today. The 'Gorilla' version has a bigger fuel tank and luggage racks.Reuse content