Classic Styling with Modern Upgrades: Kawasaki Z1B Custom Build

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PMC's Z1 [900SUPER4]

In the first article of this "JCC" series, we bring you a "Kawasaki Z1" which is the king of Japanese retro bikes tasetfully customized by PMC.

Perhaps you have noticed the "B" of the title here. The most obvious difference between the first Z1 and Z1A/B is the color of the engine, which has changed from black painting to silver aluminum surface and PMC retained this feature. But on the stock Z1B, "900" letters on the side cover were enlarged. Apparently PMC's did not restore this feature, but followed the small letters of the first generation Z1.

Engine

A full engine overhaul work is definitely in order for this 47 year old girl.

PMC used a tuned Z1000J clutch. New valves, valve guides, idlers and other wear parts, and the crankshaft was aligned and balanced. The transmission was disassembled and cleaned.

This Z1B has been big bored to 944cc displacement. PMC used a replacement piston kit that requires almost no extreme carburetor resetting to emphasize on practicality. The compression ratio is designed to be 8.5:1 for the Z1, the same as the catalog specifications. The Stock engine has been fine-tuned while maintaining its original characteristics.

The carburetor is a KEIHIN CR29 which is hard to get even in Japan. It can be used in a wide range from racing to the street.

Intake & Exhaust

S1-Type Exhaust is the root of the megaphone exhaust, which has been revisited in recent years in Moto-GP. The Blatantly machine bent 42.7mm steel exhaust pipe, a 4-in-2-in-1 system(though the collector looks like a 4-in-1 at first glance).

The exhaust system is based on the "KZ1000S1" that was used by Eddie Lawson in the AMA Superbike Championship series in the early 1980s. Now, the ultimate megaphone exhaust system is reborn with high precision and high performance by using digital 3D bender and the latest technology. It can also be said that the exhaust is essential for this Z1B custom project.

Chassis

The tire size remains the same at 18 inches, but switched from spoke to cast wheels to increase rigidity and enable a sporty and wide range of riding without ruining the beauty of the Z1B.

When working on a vintage bike with years of age, every builder does frame spray repainting to give the overall appearance of the bike a new look and cover up the signs of age. PMC was no exception, they sand blasted the full frame and painted it by urethane curing oven, but without frame reinforcement for this custom model.

Bodyworks

Rearsets equipped, the appearance of this seat is reminiscent of another beautiful machine "KZ1000S1" of the past. A unique atmosphere is achieved.

As you may have noticed the legendary body color which was only released in Europe in 1972 is used. By the way, the modern bike Z900RS SE 2022 is also in the same “Yellow Ball” livery of the original 1972 Super Four Z1 to pay tribute to the classics.

Gallery

Specifications

Part	Details
Engine	Full overhaul Z1000J clutch convertor, valve, valve guide and idler Casting Piston 1.5mm O/S
Carb / Intake	KEIHIN CR29
Exhaust	S1-Type Exhaust
Frame	Blasting, paint by urethane curing oven (without reinforcement) Stock (Wide tire processing)
Brake	Front: φ320 Rotor & CP2696 Double Disc Rear: φ250 Rotor & CP2696 Floating Mount
Wheels	Front: SWORD Evolution 2.75-18 Rear: SWORD Evolution 4.00-18
Suspension	Stock Stock (’79～’80　Z1000MK2)
Steps	Back Position Kit & Rear Master Kit
Handle / Steering	Daytona Stainless Steel Handlebar Touring Type
Seat	Seat Complete S1-Type
Bodyworks	Yellow Ball Painted Exterior

PMC(Performance Motorcycle Creative)

When it comes to KAWASAKI's Z-series custom parts, there may not be a more professional brand than PMC, even the parts compatible with the 1972 Z1. PMC has improved and grown, has been exhibited 7 times at the Tokyo Motorcycle Show. About 4,000 riders came to the 10th motorcycle festival of "West Japan Z meeting" held by PMC in 2019.

PMC(Performance Motorcycle Creative) brand page