Journey with Evolving Performance: KAWASAKI Z1(900 SUPER4) Custom by SANCTUARY

• Z1

• Share:

• 
• 
• 

SANCTUARY's Z1(900 SUPER4)

AC Sanctuary refers to the machines they customize as RCM, which stands for Real Complete Machine. These RCMs are a culmination of custom techniques gradually developed for converting Kawasaki Zs to 17-inch wide wheels. These customizations are not merely part replacements, but are created with no compromises made in any section. Over the 20 years since their establishment, AC Sanctuary has handled customizations for over 550 bikes, with the majority being Z series. Since they have been involved in many customizations over a long period of time, they have naturally encountered many users who are looking for further improvements to their RCMs.

"There are many cases where people want to refresh their bikes by updating performance, replacing parts, or overhauling them. Five or ten years after purchasing or customizing a bike, better parts, chassis, and electrical systems may become available, or more efficient methods may be discovered. So when riding a bike which has been remade, even though the numerical specs haven't changed, it feels distinctly different. Even with the same 17-inch wheels, newer models tend to have better ride quality, so it's similar to that feeling," says Mr. Nakamura, the representative of AC Sanctuary.

This Z1 Modified, RCM-442, is one such example of Sanctuary's RCM remakes. Originally, the owner, who was looking for a "fun and energetic Z," purchased a bike prepared with Sanctuary's "RCM craftsmanship" that the shop had in stock. After accumulating some miles and enjoying parts upgrades, the owner decided to go further, aiming for the ultimate specification in every aspect of the engine and chassis.

"The owner experienced higher level specifications than stock, and then wanted to take it to the next level, so we made this bike to the highest specifications that we can currently come up with. The RCM concept itself has an element of remaking or updating base bikes like the Z. For example, 17-inch conversion, frame reinforcement, and engine specs for longevity were not available when the Z was originally produced. So, you can think of it as being what a modern version of the bike would be like. It's not that the specifications made before were not good, each was the best version at the time. It's just that better options become available or we learn how to do things differently."

I see, a remake is not making everything from scratch, but an update to make it better. When you think of it that way, it broadens your horizons. I think that the enjoyment of two-stage customization like this RCM-442 will increase in the future.

Handle

A YOSHIMURA PRO-GRESS Meter has been installed on the handlebar post and the letters "RCM-442" have been added to the tachometer dial, keeping the simple yet stand-out shape of the Z1. The fork offset was also changed from the stock Z1 value of 60mm to 35mm with the Sculpture SP Stem Kit TYPE-1.

The clutch has been converted to hydraulic, and a Brembo RCS φ16 radial pump master cylinder was installed. The front brake master cylinder is also a Brembo RCS, φ19. Careful attention was also paid to the operational feel and symmetry of the appearance. The mirrors are Magical Racing carbon mirrors.

Bodyworks

The seat is a modified Daytona COZY seat. It combines a form that fits the bike body with the good urethane properties expected of a Daytona COZY seat, and is designed to provide comfort and reduce fatigue. The side covers and other parts were painted in black and yellow on a carbon base (also painted) by a custom paint store to provide an overall sense of unity with the rest of the bike. The aluminum fuel tank is made by Beater.

Engine

The engine is made to 1197 specs with PISTAL φ76mm pistons (stock stroke is 66mm). The crankshaft was buffed after a full rebuild, and the connecting rods were weight-matched + WPC machined. For the cylinder, an EST liner is used, it is bored and honed, and the top surface is lightly polished. The crankcase also underwent processing to reduce pumping loss. The head was also modified with twin plugs and WEBST-1 camshaft. After valve guides were replaced, valve seats were cut, and PAMS HF valves were installed. It is assembled with the latest specifications for active riding while taking durability into consideration.

The oil cooler is a Nitro Racing x Earl's 11-inch 13-level with more recent rubber mount brackets. The ignition is a Uotani SP2. The frame is a Sanctuary ST-II frame optimized for 17-inch wheels, with drive chain line offset track support/inline processing, etc.

The carburetor is a TMR-MJN φ38mm YOSHIMURA dual stack funnel spec. The coloring of the top cap and funnels also matches the other parts.

Chassis

Inside the front sprocket cover/outside the case, a new EVO System and Long Output Shaft by Sanctuary KOUGA have been added to make the output shaft precision double-supported, increasing the durability of the shaft section and reducing transmission vibration. This also has the advantage that the sprocket used for the wider rear tire (chain line placed on the outside) does not need to be an offset type. The steps are NITRO RACING for both rider and pillion.

The front forks are OHLINS RWU Noblest ExM package specification and the wheels are OZ Racing aluminum forged GASSRS-A, sized 3.50-17/6.00-17. The brake calipers are Brembo CNC .484, and this is one of the changes from the Craftsmanship specs. The brake discs are SUNSTAR Premium Racing RCM Concept ø320mm, and the brake lines are a one-off from Allegri.

The swingarm is a SCULPTURE RCM exclusive wide swingarm in black coat finish, with lower sway bar and racing stand hooks added. The rear shocks are anodized NITRON Stealth Twin. ENUMA EK530RCM was chosen for the drive chain.

The rear brake calipers have also been replaced with Brembo CNC. The discs are SUNSTAR ø250mm and the brake lines are by Allegri. The exhaust is NITRO RACING Weldcraft Titanium 3D and a NITRO RACING Grenade Titanium V-3 Silencer is installed for the silencer.

Gallery

Specifications

Part	Details
Engine	PISTAL φ76mm Forged Piston WEB ST-1 Camshaft PAMS HF Valve (Plus)
Carb / Intake	YOSHIMURA MIKUNI TMR-MJN36 Carburetor YOSHIMURA DUAL STACK FUNNEL SYSTEM Basic Kit YOSHIMURA Original Aluminum Funnel for TMR/MJN
Exhaust	NITRO RACING 4-in-1 Weld Craft Titanium 3D Exhaust System NITRO RACING Grenade Titanium Silencer Version 3
Frame	SCULPTURE SP Stem Kit for Z1/Z2 Φ43 Fork [Type1] SCULPTURE R.C.M Wide Swingarm Racing Stand Hook Sway Bar Black Coat
Brake	brembo Racing Radial Brake Master Cylinder (19 x 18) brembo 484 Café Racer Radial CNC 4P Caliper SUNSTAR Premium Racing RCM Concept φ320mm Brake Disc ALLEGRI Shorto System Brake Line brembo GP2-CR CNC 2P Rear Caliper SUNSTAR Premium Racing φ250mm Brake Disc
Wheels	OZ Racing GASS RS-A Forged Aluminum Wheel
Suspension	OHLINS Upright Front Fork RWU NITRON Rear Suspension Twin Shock TWIN R3 Series
Steps	NITRO RACING Rearsets NITRO RACING Pillion Step Bracket Kit Universal Type 2
Drive System	brembo RCS Clutch Master Cylinder NITRO RACING Clutch Release Plate Kit Type 2 SANCTUARY KOUGA EVO 5-gear Kit SANCTUARY EK & NOBLEST 530 RCM Chain (BK / GP)
Handle / Steering	Magical Racing NK1 Mirror TYPE-6 POSH Super Low Bar YOSHIMURA PRO-GRESS2 Multi-temp Meter
Oil Cooler	NITRO RACING EARL'S Oil Cooler Kit
Seat	DAYTONA [DAYTONA x AC SANCTUARY] RCM Concept COZY Seat
Bodyworks	Beater Aluminum Tank
Electrical	AS Uotani SPII Full Power Kit

About SANCTUARY

SANCTUARY is a custom builder that is good at Vintage motorcycles like Z1,Ninja and KATANA. They sell special parts which were born from trial and error that mechanics had repeated mounting and testing

SANCTUARY brand page

Original Source of this Article

Heritage & Legends