Giving Back to the Z with Thoughtful Upgrades: KAWASAKI Z1(900 SUPER4) Custom by AMERICAN DREAM

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AMERICAN DREAM's Z1(900 SUPER4)

American Dream is a builder that has been focusing heavily on the Z900RS. This Z1 was shown at the 2025 Tokyo Motorcycle Show in spring, alongside the shop’s latest Z900RS demo machine. Like the Z900RS, it is equipped with American Dream’s newest part, the Café Racer Cowl Kit Type-2, but the build goes much further. The shop had previously shown some in-progress parts such as the step kit and oil cooler and these have now been completed and fitted to the bike.

“Customers often told us they wanted steps that allowed for a more relaxed riding position. Many aftermarket products for the Z place the footpegs too high and too far back, while the stock Z position is the opposite—too far forward. When I tried the Z900RS, which we also focus on, I felt its step position was much more comfortable. Looking again at the relation between seat and steps, it all made sense. That’s what led us to create this new design. The five selectable peg heights are there because a pipe handlebar and clip-ons don’t share the same ideal position. We wanted each setup to have its best possible match,” explains Matsuda of American Dream.

For customers who still can’t decide, the shop offers an extra service: they send a plate with ten more peg positions (five forward, five back). The customer tries it, decides on the best spot, and sends the plate back. The shift rod connecting the pedal and shaft is also designed so the mounting height at the rear of the pedal can be changed depending on riding style—showing how much thought was put into rider feel and operation.

The large-core "Racing" oil cooler installed on this bike was developed for riders who ride their Z hard on winding roads and highways. For those who don’t ride that way, a smaller-core “Street” version is also available, and it is said to be very effective. Another new part is the engine hanger. Machined from aluminum, it firmly holds the engine in place and features an aggressive weight-reduction design unlike anything seen before.

So why is American Dream also putting effort into parts for the air-cooled Z, when the Z900RS parts business is going so well? “We’re grateful that Z900RS parts are selling so well, but we can’t just leave the Z behind. The Z has supported us since long before the shop even opened, so I really want to give back to it. That’s why I’m willing to make the parts I want, putting my vision and quality first, even if it costs more,” says Matsuda. This new batch of parts is a clear reflection of that mindset. Insights gained while working on the Z900RS—like with the step kit—have given the team fresh ideas when revisiting the Z1, the predecessor of the Z900RS.

But that doesn’t mean they’re shifting focus away from the Z900RS: “It’s not just the Z—we’ll keep pushing the Z900RS as well. Both bikes are full-time priorities. We’ll keep developing them side by side, on the track and on the street, and we also plan to make new step kits for the Z900RS.” The two bikes, separated by 50 years, are treated as two main pillars. By occasionally comparing specifications between them, the team can apply the strengths of one to the other, adding even more depth to future parts and builds.

Handlebar

Fitted with American Dream’s new Z1/Z2 Café Racer Cowl Kit Type-2, designed with a sharper, more race-oriented look than the earlier Type-1. A Magical Racing NK-1 mirror (Type-2 head) is mounted on the cowl bracket. The bodywork is finished with MagiVeil coating. The stem is American Dream’s PRIDE, and the bike uses ACTIVE clip-ons. The front brake master cylinder is a Gale Speed VRC, and the wire clutch holder kit is also from Gale Speed. A Stack ST200 speedometer is installed inside the stock case.

Engine

The new Racing Round Oil Cooler from American Dream is designed for riders who cover long distances on twisty roads and highways. A smaller Street Oil Cooler is also available for everyday riders.

The engine has been big bored to 1105cc with Pistal Racing forged 73 mm pistons and EST sleeves. The crankshaft has been fully overhauled, and the transmission features dog gears, which allow quicker and more precise shifts. It also uses Yoshimura ST-2L cams, PAMS valves, and Bulldog/McCoy cylinder stud bolts. To ensure adequate oil flow for the Racing Round Oil Cooler, a NOBLEST Trochoid-type oil pump has been added. The billet clutch release kit is from PMC’s DRAFT brand.

The carburetor is a TMR-MJN φ38mm with dual-stack funnels in black and gold.

The new engine hanger from American Dream comes as a set (front, lower, and rear). All are made of CNC-machined aluminum. They firmly hold the engine and have bold weight-reduction cuts for added style. Available in silver or black.

Chassis

The bike is equipped with American Dream’s new Riding Step Kit, described earlier.

This kit has a two-block structure: a mounting base (the part that attaches to the frame, shown in black in the photo) and a step-bar mount (shown in silver). Selecting different holes in the base allows for five peg height positions. Several mounting holes under the shift pedal also let the rider adjust shift feel by changing the angle between the pedal and the shift shaft.

The front forks are Hyperpro AH1, paired with Brembo axial 4-piston calipers and Sunstar x American Dream Spec rotors.

At the rear, a Brembo P2-CR842P caliper is paired with a Sunstar x American Dream rotor.

The rear suspension uses Hyperpro DP-S twin shocks, and the swingarm is from the American Dream Black Line series, originally for the Zephyr 1100, now being tested for the Z. Wheels are MAGTAN JB4, sized 3.50-17 front and 6.00-17 rear, with BRIDGESTONE RS11 tires in 120/70ZR17 and 190/55ZR17.

Gallery

Specifications

Part	Details
Engine	PISTAL RACING φ73mm Forged Piston Kit YOSHIMURA Camshaft [ST-L2] AMERICAN DREAM Engine Mount Plate Set for Z1/Z2 SANCTUARY MECHANIC BRAND Z High-Pressure Oil Pump Kit (YRP Racing Type)
Carb / Intake	YOSHIMURA TMR-MJN Carburetor YOSHIMURA Dual Stack Funnel System Basic Kit for TMR YOSHIMURA Original Aluminum Funnel for TMR/MJN
Exhaust	AMERICAN DREAM Neo Short Exhaust / High-Mount Type Titanium for Z Series AMERICAN DREAM PRIDE Stem Kit Black for Z Series
Frame	AMERICAN DREAM Black Line Swingarm for Zephyr 1100
Brake	GALE SPEED VRC Brake Master Cylinder (Front) brembo P4-40C Axial 4-Piston Caliper (Front) AMERICAN DREAM x Sunstar Collaboration Special Edition Disc (Front) brembo P2-CR84 Rear Brake Caliper P2 34 84mm AMERICAN DREAM x Sunstar Collaboration Special Edition Disc (Rear)
Wheels	JB POWER MAGTAN JB4 3.50-17 (Front) JB POWER MAGTAN JB4 6.00-17 (Rear)
Suspension	HYPERPRO AH1 (Front) HYPERPRO DP-S Twin Shocks (Rear)
Steps	AMERICAN DREAM Riding Step Kit for Z Series
Drive System	PMC Billet Clutch Release Kit
Handlebar / Steering	ACTIVE Clip-On Handlebar GALE SPEED Wire Clutch Holder Kit STACK ST200 Clubman Tachometer Magical Racing NK1 Mirror TYPE-2 YOSHIMURA PRO-GRESS2 Multi-Temp Meter
Oil Cooler	AMERICAN DREAM Racing Round Oil Cooler Kit for Z Series
Bodywork	AMERICAN DREAM Cafe Racer Cowl Kit Type 2

About AMERICAN DREAM

AMERICAN DREAM, which offers customized parts of, mainly, Kawasaki big motorcycles such as Kawasaki air-cooled Z, GPZ900, ZRX. Exhausts or cowl seats from the original products, PRIDE series, are very high quality!

AMERICAN DREAM brand page

Original Source of this Article

Heritage & Legends