Every Detail Counts: KAWASAKI Z1 (900 SUPER4) Custom by BULL DOCK

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BULL DOCK's Z1(900 SUPER4)

This Z1 sports the iconic Tiger pattern of the air-cooled Z, applied with precision, while its base color—metallic orange—adds both lightness and depth to the overall impression. This is one of BULL DOCK’s complete custom builds, known as the GT-M (Genuine Tuning Machine).

“The engine is built to what you’d call 1170cc, using forged pistons from Pistal Racing. The transmission is our original 5-speed close-ratio, paired with a TSS slipper clutch. The alternator kit is also Mccoy. It’s been thoroughly worked over,” explains Mr. Wakui of BULL DOCK. What stands out first is just how modern those specs are—like you’re reading about a brand-new bike. As we always mention when introducing BULL DOCK’s bikes, this comprehensive menu is practically everything you need to keep an air-cooled Z both reliable and high-performance.

Because they handle even the internal engine machining in-house, they can build the entire package with confidence. What’s more, they can flexibly adjust specifications such as displacement and details based on the owner’s preferences. Naturally, that includes the finish of the covers, the paintwork, and the colors. Even if repairs are needed after purchase, you can feel reassured knowing they have the parts (special, but not rare or hard to get) and the support to take care of everything.

On the chassis side, the frame is designed with the crankshaft as the reference point to create geometry that works with modern 17-inch wheels. The wheels, suspension, brakes and other parts are also carefully balanced to match the much lighter chassis.

On top of this consistent, well-thought-out construction, the bike also reflects the owner’s personal tastes down to the paintwork, handlebar choice, and other small parts. That’s why each of these bikes is made to be enjoyed for many years. For the viewer, too, it makes you want to keep looking closer and noticing more details. Perhaps that’s the magic behind the GT-M.

Handlebar

The left and right master cylinders are Brembo RCS, and the mirrors are Magical Racing NK-1 with Type-6 heads. The turn signals are a small type.

The steering stem is made by Mccoy, and a YOSHIMURA PRO-GRESS meter has been added. The wiring, including the throttle and clutch cables, is neat and simple.

Bodywork

The seat is a Mccoy Supreme, which is comfortable and improves control. The bodywork is painted with a metallic orange base and Tiger pattern.

Engine

The cylinder head cover has a red wrinkle finish and an oil cooler has been added. The carburetor is a YOSHIMURA FCR-MJN with black wrinkle-finish top covers.

The engine has been big bored to 1166cc with Pistal Racing φ75mm (stock is 66mm) forged pistons. It also has a Mccoy 5-speed close-ratio transmission, a high-capacity dynamo and one-way clutch kit, and a TSS slipper clutch, all of which greatly improve reliability. The engine covers are also Mccoy.

Chassis

The front fork is an Ohlins RWU. The front brakes are Brembo billet radial calipers with SUNSTAR discs and Mccoy pins.

The rear brakes are a Brembo CNC caliper with SUNSTAR disc and Mccoy pins. The exhaust system is a full titanium Win Mccoy full exhaust.

The rear shocks are also Ohlins, and the swingarm is a Mccoy, made of 7N01 aluminum with a pentagon-shaped cross-section. The wheels are Marchesini forged aluminum M7RS, sized 3.50-17 front / 6.00-17 rear, fitted with BRIDGESTONE RS10 tires in 120/70ZR17 front and 190/50ZR17 rear sizes. The rear inner fender is made of carbon fiber.

Gallery

Specifications

Part	Details
Engine	PISTAL RACING φ75mm Forged Piston MCCOY 5-Speed Close-Ratio Transmission MCCOY TSS Slipper Clutch MCCOY Point Cover
Carb / Intake	YOSHIMURA FCR-MJN Carburetor
Exhaust	BULL DOCK Win Mccoy Full Exhaust System BULL DOCK Win Mccoy Silencer
Frame	MCCOY Standard Stem Kit for φ43mm Upright Forks MCCOY Swingarm
Brake	brembo RCS Brake Master Cylinder (Front) brembo Racing Radial CNC 4P Calipers (Front) MCCOY x SUNSTAR Disc Rotors φ320 (Front) MCCOY Master Cylinder (Rear) brembo CNC 2P Caliper (Rear) MCCOY x SUNSTAR Disc Rotor (Rear)
Wheels	MARCHESINI M7RS Genesi 3.50-17 (Front) MARCHESINI M7RS Genesi 6.00-17 (Rear)
Suspension	OHLINS RWU OHLINS Legend Twin (KA132)
Steps	MCCOY Rearsets TYPEⅡ
Drive System	MCCOY Offset Sprocket Outboard Kit RK 520XXW Drive Chain
Handlebar / Steering	brembo RCS Clutch Master Cylinder Magical Racing NK1 Mirror, TYPE-6 YOSHIMURA PRO-GRESS2 Multi-Function Meter
Seat	MCCOY x SUPREME Seat
Bodywork	MCCOY Carbon Rear Inner Fender
Electrical	MCCOY Dynamo / One-Way Clutch Kit

About BULL DOCK

A motorcycle customization and tuning store focused on the Kawasaki Z series. The "Mccoy Series" is the original parts developed by BULL DOCK in pursuit of further performance for the complete machines. Each and every one of these parts is manufactured with a strong sense of commitment.

BULL DOCK brand page

Original Source of this Article

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