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Pursuing High Quality Riding with YSS Forks: Z1-R Custom

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 9 min read

POWER BUILDER's Z1-R

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The owner of this Z1R has been riding the bike for over 15 years. In those days, he has been around various custom stores and has repeatedly changed specifications. The engine was the first thing that prompted POWER BUILDER to get involved. The engine was tuned appropriately at that stage, but he asked the POWER BUILDER to refine it. Eight years ago, the engine was upgraded to the current specifications. The engine is now 1,166cc with Cosworth pistons, APE camshaft, twin plugs, and the curvature of crankshaft has been adjusted, and the owner is very satisfied with the results. The engine was converted to the current specifications eight years ago, although it has been driven a considerable number of miles in those eight years, it is still powerful enough to wheelie even without an overhaul.

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The owner has visited various custom stores over the years to change the chassis, but now leaves it to the POWER BUILDER. However, the owner also wanted to use YSS front and rear shock absorbers, which is a rare configuration for POWER BUILDER. The owner's first reason for choosing YSS was partly because he wanted to change the look of the bike, including the coloring, but of course, POWER BUILDER would never customize a bike just for looks. The reason why the owner had been going from one custom store to another is because he had high objectives for riding performance. The owner's high objectives are embodied in, and the POWER BUILDER's know-how has been fully incorporated into this bike.

Electrical

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The tachometer was changed to a Nagai Denshi's Ultra series to improve reliability. The meter looks like the stock meter and does not look out of place, but the installation is said to be a very difficult and time-consuming process.

Engine

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The engine was tuned by POWER BUILDER 8 years ago, although it has traveled a considerable distance, it has not been overhauled except for a tappet adjustment. It is still more than enough powerful and wheelie easily.

Intake & Exhaust

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The exhaust system is a machine-bent titanium megaphone from POWER BUILDER. The machine-bent exhaust system was chosen to match the atmosphere of old bikes and classic bikes with old tastes, instead of a sleek hand-bent exhaust system. The spiral collector makes it easier to handle.

Chassis

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JB Power Magnesium Forged JB3 wheels were chosen for both front and rear. These are POWER BUILDER's most trusted wheels and have been used in many cases. Radial-mounted monoblock brake calipers were selected.

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The rear shocks are YSS SII 362, which is also supported by Taste of Tsukuba, and POWER BUILDER's know-how is also incorporated into this machine for high road-following performance.

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This unique swingarm was installed by the owner when he was moving from one custom store to another in the past. It was probably made by TRAC, but the length and the rigidity were not a problem, so he continues to use it.

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The rear brake also features Nissin 2-pot caliper and Φ260mm rotor for controllable operation. Like the front wheel, JB-Power Magnesium Forged JB3 wheels are 4.50mm, not too wide.

Electrical

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The data logger was made by Drogger, and sensors were placed at the rear end of the seat rail to research the movement of the motorcycle body. The electrical components were also changed for convenience, such as placing them under the seat and the AS Uotani SPI ignition coils inside the side cowl.

Intake & Exhaust

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The exhaust system is special order made by Nojima Engineering for POWER BUILDER. The unique spiral collector is highly trusted by POWER BUILDER for its effectiveness in all aspects, including acceleration, deceleration, and RPM extension.

Gallery

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Specifications

Part Details
Engine COSWORTH Piston Φ75mm
APE 435 Camshaft
Carb / Intake KEIHIN FCRΦ37mm
Exhaust POWER BUILDER Machine Bent Megaphone Exhaust
Brake NISSIN Radial 4Pot Front Brake Caliper
NISSIN 2Pot Rear Brake Caliper
SUNSTAR Front Brake Disc
SUNSTAR Φ260 Rear Brake Disc
Brembo Radial Master Cylinder
Wheels JB-POWER Magnesium Forged Wheel JB3
Suspension YSS KG308R Front Fork
YSS Rear Suspension SII362
Steps MORIWAKI Rearsets Kit
Handle / Steering SCULPTURE Bracket
Oil Cooler EARLS Oil Cooler
Electrical ASUotani SPII Full Power Kit
ULTRA Tachometer

About POWER BUILDER

"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.
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POWER BUILDER brand page

Hakuyo
Hakuyo

editor

Hakuyo

A foreigner who rides in Japan, Japanese call this "Gaijin Rider". Third year in the Webike global team. He feels and shares the real bike life in Japan then presents you how interesting Japanese customs are.