PERFECT INCH: Close up of the A16 demo bike from AC Sanctuary


If there is any Proof that motorcycles are a global language, it’s the worldwide fame of AC Sanctuary. The Japanese workshop was established in the mid-1990s by mechanic Hiroyuki Nakamura.

This is despite the fact that Nakamura-san and his crew do not speak English. The company’s website is often monolingual as well, and until three years ago, AC had no outside representation of any kind.

AC Sanctuary RCM A16

Asphalt Cowboys opened a small office in Gardena, California, to facilitate the passage of parts and bicycles into the United States. And then they shipped via the bike shown here — to potential customers to test-ride, presumably before delivering a few million yen to Japan for a replica.

This bike is based on the classic Kawasaki ‘Zed’ platform, on which AC has built its name. It’s one of a new series called the A16, with production planned for 30 bikes, and it’s now back in Tokyo.

AC Sanctuary RCM A16

Eight A16s have already been built in Japan. The machine shown here is #4 in the sequence, a test mule part, and a test bike part.

Like most Kawasaki designs from AC, this A16 is towing with advanced parts. The recipe is familiar: a custom frame, albeit loosely based on the original Kawasaki version, plus Öhlins suspension. The wheels are supplied by OZ Racing, the brake calipers are from Brembo, the discs are from Sunstar, and the exhaust system is from Nitro Racing.

AC Sanctuary RCM A16

The A16 platform includes many new improvements, many of which are subtle but effective modifications to the frame geometry. “The standard Sanctuary Z-type tire is not a fit frame for the characteristics of modern high-spec radial tires,” explains Nakamura.

The point is that the A16 tires are specifically designed for 17-inch wheels and high-performance rubber. That means repositioning the steering necks, improved stiffness, and redesigned swingarm axles. The swing arm itself is a classic double-sided unit, which has been given additional width and strengthening.

AC Sanctuary RCM A16

Many of the new parts are designed in CAD, and then made from SS400 alloy steel. Even the engine mounts have been redesigned, since racing experience has shown that mounts can have a surprising effect on maneuverability. The upper nut on the steering stem is a modern Ducati element, chosen for its tight manufacturing tolerances, and the rails are a new, slightly tilted design.AC Sanctuary RCM A16

Nakamura calls the changes a “transformation,” and says the handling of the A16 series is “practical.” “It’s not just racing,” he says. “It’s something you can fully experience even at legal speeds. It’s easy to ride even while on the go or in town.”

This easy nature is underpinned by the smooth power from the heavily modified KZ1000 engine—the inline four engine familiar to the AC Sanctuary mechanic.

AC Sanctuary RCM A16

AC has traditionally replaced the stock carb with a sporty setup—like the 38mm Yoshimura Mikunis—but in this case they switched to fuel injection.

Kawasaki’s attempt at a large, air-cooled engine injection in 1980 didn’t go well, but you can guarantee the Nakamura crew did a good job. They didn’t have much choice in the matter: Under Japanese law, this machine is technically a 2016 bike, and therefore must meet that year’s emissions regulations. It’s an issue that AC will increasingly be facing, so they’ve dealt with it head on.

AC Sanctuary RCM A16

Not many stores tend to develop an EFI system that works with an old motor, but AC has been using these motors for more than two decades – and there’s no old school about their approach. In Tomin’s recent “micro-circuit” short-track getaway test, the EFI programming on this A16 was repeatedly improved upon following feedback from test riders.

On the A16, the metal parts of the engine are also in better condition than when it left the factory. Once an engine is acquired, it is stripped, stripped, and refinished. Everything that is worn is replaced, with goodies including the big valves and Vossner pistons. All mounting hardware is new and improved, as is the entire clutch assembly.

AC Sanctuary RCM A16

Frame modifications mean a new chassis. The GRP tank sits on a new fuel cell design, and the seat unit is a one-piece assembly that lifts when the key is turned.

The A16 is at the forefront of custom technology, but Nakamura-san is drawing the line in things like LED lighting. The flickers are chunky, and the brake light is massive by modern standards. But everything seems “okay”.

AC Sanctuary RCM A16

This A16 may return to Tokyo shortly after his stay in California, but the local AC office can still receive your application. You’ll likely find yourself turning to Google Translate a lot, but it’s worth it.

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AC Sanctuary RCM A16

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