power-builder_z1000_01-1009x672-1.jpg CUSTOM
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Kawasaki Z1000 Custom by POWER BUILDER

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 10 min read

Japanese Custom Culture

Here is an original series "JCC" stands for "Japan Custom culture" written by Webike Japan. There is no doubt that Japan has one of the best and unique custom parts and its culture in the motorcycle industry, but the language barrier has led to the closure of JDM motorcycle culture to the outside of Japan. Through this JCC contents, we present you one of a kind custom and mods bikes by professional craftmen and enthusiasts who just can't stop loving motorcycle.



The bikes looks like an air-cooled KZ1000, but the engine is clearly water-cooled. The exterior fittings are quite elaborate, although this can be said to be the playful mind of the power builder, Mr. Harigae, who produced this bike. Some might think that a water-cooled engine was installed on an air-cooled frame, but the frame is a genuine 2004 Z1000. Although many of the parts are reused from surplus parts, it is not a case of "gather of junk parts", so we put them together to make one real machine. As a machine built by a power builder, every part of the machine has been thoroughly built.


Power Builder is a custom store in Japan well known for engine tuning. Therefore, the Z1000 engine was not just reassembled. The representative of Power Builder explains as follows.

"When we customize the Z1000, we often use ZX-9R camshafts for higher lift, but the ZX-9R camshafts have press-fit cam sprockets. However, the ZX-9R camshafts have press-fit cam sprockets. Therefore, even if the cylinders and head are surface ground, the valve timing cannot be optimized. Therefore, the Z1000 is considered to have an upper limit of 130 to 135ps, but that is not interesting. We changed the cam sprocket to a sliding type to allow for valve timing, and then surface grinding was done to optimize the valve timing. The new valve timing is now capable of achieving 149㎰."



Although surface grinding of the cylinder head to increase the compression ratio is an effective method to increase power with the stock pistons, the maximum effect cannot be obtained unless the valve timing is optimized. Therefore, the they found an external sliding camshaft for the ZX-9R and optimized the combustion efficiency.



As is typical of racers, the instrumentation is very simple. The only gauges are a Stack tachometer and Yoshimura's digital multi-monitor for reliability. The brackets are from a GSX-R1000, and the handlebars are genuine Yamaha R1. The bracket on the neck is for the tank.



The electrical components are concentrated directly above the engine, where the gasoline tank would normally be located. Parts such as Evoltech's lithium-ion battery and racing igniter for ZX-9R can be seen. The bracket on the right is for the tank. The dummy tank is inserted from above.



The front fork is a GSX-R600 (Showa inner cartridge). Of course, it was not just a simple modification, but the internals were modified as well. The spring rate is optimized for the Z1000.


The rear shock is the reliable and proven Öhlins TTX, and the linkage chosen was for the ZX-6R in order to achieve the lever ratio that the Power Builder insists on. Of course, the same behavior as this machine cannot be obtained by using TTX rear shocks with ZX-6R links. That's where the expertise of a professional builder comes in!


The brakes are all Brembo racing parts. The calipers are monoblock GP4-RR, and the rotors are 305mm in diameter for racing use. The JB Power JB5 wheels are said to have been prepared for racing use by Kawasaki.


The fuel tank itself was modified from a custom-made seat rail to allow the installation of a single seat docked to the side cowl, and the fuel tank was relocated to the space under the seat.


The Z1000 is said to have weak strength under this pivot, and cracks can occur even in bikes that are not driven on the race track. Minimal reinforcement was added to take such weaknesses into account.



Rearsets are made by Woodstock. Woodstock parts are so reliable that they are used by racing teams with strong ties to Kawasaki, such as RS Ito. This reliability was also taken into consideration when installing these parts.

Intake & Exhaust


The exhaust system is a FASAM Pro Titanium with a Nojima Engineering Lock-On II silencer; since there is no uprated version for the Z1000, they commissioned this special to be made.


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Part Details
Engine Camshaft: ZX-9R OEM
Mission: ZX-9R OEM
Radiator: ZX-10R OEM
Carb / Intake Mikuni TMR Φ40mm
Exhaust Nojima Lock-On II Full Exhaust (Custom-made)
Brake Brembo Monoblock GP4-RR
Brembo Racing Rotor 305mm
Brembo Racing Radial Brake Master Cylinder (19×18)
KOHKEN BREMBO Rear Caliper Kit
Rear Brake Master: YAMAHA OEM
Wheels Front: JB Power Magnesium forged wheels JB 3.50-17
Rear: JB Power Magnesium forged wheels JB 6.00-17
Suspension Front Fork: GSX-R600 OEM
Inner Tube: SHOWA
OHLINS Rear Suspension TTX-GP 2018
Handle / Steering Bracket: GSX-R1000 OEM
Handle: YZF-R1 OEM
Seat POWER BUILDER Custom-made
Bodyworks Paint: BP Nakayama
Electrical Ignitor: ZX-9R OEM Racing Kit


POWER BUILDER" is a winning tuner in the Taste of Tsukuba, Japan's premier Sunday race for steel-frame bikes from the 80s and 90s. Power Builder" is a tuner who always wins the Taste of Tsukuba, the most prestigious Sunday race in Japan, where the best bikes from the 80s and 90s compete. Power Builder" is not a restoration company, but rather a company that creates power, a company that is thoroughly committed to creating products that live up to its name.


POWER BUILDER brand page