AC Sanctuary It is literally a place where TOancient clasics reach the YesJapanese two-wheeled sanctuary, located in Kanagawa prefecture, and undergo a lifting complete through an unsurpassed restomod process. In it, good old Nakamura spends entire weeks, together with his trusted team, putting into practice a restoration and improvement process in which craftsmanship and innovation become the main protagonists.
The final result of all this dedication and mastery ends up becoming motorcycles as spectacular and unique as this one. RCM-667 KZ900. In it we can see. Once again, like an old Kawasaki from the late seventies, it can be transformed into an efficient and effective naked sporty frame that looks like it just came out yesterday from one of the official dealers of the Akashi brand.
RCM-667 KZ900: “the secret is inside”
It is undeniable that this RCM-667 KZ900 shines with its own light in visual matters. Nothing about it would make us suspect that we are looking at a motorcycle with half a century of life behind it. However, as Nakamura himself explains in his personal blog, due to the changes implemented in it, its greatest success lies in what is not seen:
“I was very impressed by how happy the owner was when he picked it up, saying, ‘Wow! It’s completely different!’ In fact, I imagine you were surprised, as the vehicle now looks completely different than when you brought it in. But what’s really changed is not just the appearance, but the internal components; the performance should be far superior.”
And if we talk about performance, to put into context what the KZ900 represented at the time, it came equipped as standard with an 898 cc four-cylinder engine, air-cooled and associated with a 5-speed gearbox. At the time the brand declared 81 HP at 8,500 rpm and a maximum torque of 73.5 Nm at 7,000 revolutionswith an approved top speed of the order of 200km/h.
Now, when we observe the infinite changes carried out by AC Sanctuary on the original model, we are aware that those official data from the original 1976 model have gone down in history. As Nakamura details, the engine has been completely revised and updated by DiNx, “which has resulted in torque and power that are on a completely different level than before”he states.
To achieve this, state-of-the-art elements present in most of the Japanese specialist’s preparations are used, among which a battery of flat-gate carburetors and a titanium Nitro Racing exhaust system stand out. Also the conversion of the clutch to a hydraulic type, a modernized cooling system with a Nitro Racing oil cooler and, for its proper functioning, a latest generation trochoidal oil pump.
An updated overall set that is exciting
The second part of this restomod process rotates, as is usual in all “Real Complete Machine” work of AC Sanctuary, in its cycle part, as well as the equipment and final finishes responsible for decorating the project. In this section Nakamura explains: “The vehicle they brought us had 18-inch spoked wheels both front and rear, which gave it a classic and vintage look that is currently in fashion”
To begin to open its mouth, the chassis received what the Japanese trainer calls “Stage 2 reinforcement”. In addition, both the battery case and other components have also been redesigned to match the structure of the model. Subsequently, a pair of 17” OZ Racing forged wheels were installed, shod with Pirelli Diablo Corsa IV tires, measuring 180 mm on the rear axle.
Regarding this modification, Nakamura explains that, by switching to this tire configuration, “unsprung weight reduction is among the highest of any brand available.” It also clarifies that “They also meet dynamic performance requirements, including straight-line stability during full acceleration, direct braking feel, and improved tire traction performance.”
But in order to install a rubber of this size on the RCM-667 KZ900, the rear section of the motorcycle must be completely modified by moving the chain line from 21 mm to 23 mm. Because of this totally necessary change, it is Nakamura himself who claims to be surprised that many people today are unaware of this type of information when undertaking a project of this magnitude.
The rest of the cycle part is controlled by an Öhlins suspension system that includes “the premium E×M package, which combines fully adjustable 43mm conventional forks with matching Blackline rear shocks”explain the colleagues of Pipe Burn. The seatposts, signed by the Nitro Racing brand, along with the braking system, with Sunstar discs and Brembo radial calipers complete this section.
The final touch is in the details
Finally we have the level of equipment and finishes that AC Sanctuary prints on each and every one of its creations, but in this RCM-667 KZ900 they highlight the final result of the set even more. Starting with the Daytona RCM Concept handlebars and weights and ending with a seat from the “Concept COZY” house. Once the entire process was completed, the motorcycle was delivered to its owner. “during the rainy season”says Nakamura.
This concludes with a phrase that gives meaning to the work, effort and dedication that must be done to give life to something as incredible and unique as this RCM-667 KZ900: “but luckily it didn’t rain on delivery day! I hope you enjoy the ‘pleasure of looking at it’, the ‘pleasure of driving it’ and the ‘pleasure of owning it'”…All said.
