This Incredibly Rare 1966 Honda S600 is an Evolutionary Link Between Honda’s Cars & Motorcycles (It’s Chain Drive, Too!)

Thanks to a big push into the scooter market in the early 1960s, Honda quickly built a reputation as a major motorcycle manufacturer—but automobiles were already on the company’s horizon.

Long before the N600/Z600 arrived in the United States, Honda released the tiny T360 truck in Japan in 1963.

Less than a year later, it unveiled the S600.

Produced from 1964 to 1966, Honda only made around 13,000 S600 models in that short timespan. It’s considered Honda’s first mass-marketed automobile, and the first one it designed with left-hand and right-hand drive options for export—though it never officially came to the United States.

That means they’re super, super rare over here, so when we spotted this one at a recent Cars & Coffee event, we had to track down its owner to learn more.

“Only 72, I think, are in this country that have an owner and a VIN,” Karl Munson says. “Approximately half of those are running.”

About five years ago, Munson was searching for a British roadster like the one he had in college. “But when I saw this one at an auction up in Maine,” he quips. “I knew I had to have it.”

So, how does a car that was never sold in the U.S. get across the Pacific?

This particular S600 is a 1966 model that was originally owned by an American Serviceman stationed in Okinawa, Japan. “He had it specifically set up with left-hand drive because he knew he would take it home to the States,” Munson explains. The car was also optioned with rare features like a factory luggage rack, back-up lamps, heater, and AM radio that cleverly integrates the antenna into the windshield visor.

It was in pretty good shape when Munson got it too, needing only small mechanical fixes and some minor bodywork to remedy a few bubbles forming on the roadster’s steel body.

Under the hood of the S600 lives a 606cc powerplant that, as Munson describes, was designed and built specifically for this car. It makes 57 horsepower and 37 lb.-ft. of torque, which can propel the 1,600 pound roadster to a top speed of around 90 miles per hour, and from zero-to-sixty in about 16 seconds.

While the engine was bespoke for the S600 automobile, it borrowed plenty from Honda’s motorcycle expertise—which is evident when you see the tachometer’s astronomical 9,500 rpm redline.

In fact, Munson tells us about a gentleman in nearby Dayton, Ohio that raced these back in the day. He recalls that, in fighting trim, the engine would rev-up to 11,000 rpm all race long, all season long with little more than carburetor adjustments between events!

The engine features an aluminum block and benefits from dual overhead cams, hemispherical combustion chambers, a roller bearing crank(!), and full-length headers, much of which developed out of Honda’s motorcycle program. Fans of early Honda bikes will immediately recognize the four Keihin carburetors too.

It’s got a hydraulic clutch, along with a single hydraulic brake circuit pushing drums at each corner.

Oh…and did we mention it was…chain drive?!?!

Two chain drives, actually—we’ll let Munson explain it:

“It has a conventional four-speed [manual] transmission. The drivetrain comes back to a differential that’s actually bolted to the chassis. There are two stub shafts that come out to each wheel with a sprocket on the end. And the sprocket drives a short chain to the wheel.”

So yes, if you roll underneath the back of the S600, you’ll see a large chain case tucked behind each rear wheel. There’s an individual chain inside each aluminum housing, which connects a drive sprocket on the axle half-shaft to an offset driven sprocket on the wheel. The differential itself has 1:1 ratio, with the sprockets handling the gear reduction.

Dig old Hondas? You may enjoy this article too: How Transparent Fuel Lines Helped Solve a Decades-Old Motorcycle Idle Problem

If that wasn’t ingenious enough, the cases actually serve as coil-sprung trailing arm suspension members, which means the S600 has an independent rear suspension.

“The differential is always parallel with the body. The tires are always vertical,” Munson explains. “Camber is fixed with no adjustment, and the chains are easily adjustable with a simple tensioner arm.”

How can you tell if the chains need adjustment? “It gets noisy!” he laughs.

Though Munson does allude to some drawbacks with this particular setup, namely the complexity of the system with its three separate cases that add some unsprung weight to an otherwise light-footed car. (Honda must’ve agreed, as it went to a conventional solid axle shortly after the introduction of the next generation S800 model.)

We asked Munson what he’s done with the car since it entered his stable, and he says it’s actually nabbed first place at a pair of concours-level car shows already, narrowly missing best-in-show honors both times.

“Basically, I’ve been a Bridesmaid twice,” he jokes.

Despite the car’s rarity, Munson isn’t shy about driving the S600 either, and it’s no stranger to the interstate. “Yeah, on paper, top speed’s 92 miles per hour. But you’ve got to have a real smooth road—and we don’t have many of those in Ohio,” Munson chuckles. “It loves 70 [mph] though.”

With that, we thanked Munson for his time and let him get back to answering questions from the dozens of other folks crowding around his delightful, diminutive roadster.