In 1972, Kawasaki unleashed the 903cc Z1 on the world, a four-cylinder freight train destined to outclass every other production street bike on the planet:
“With one stunning model [Kawasaki] scooped up all the prizes for speed and power and muscle and status, while the former kings muttered about only 750cc or only two cylinders.” —Cycle World, 1976
But times were changing quickly, and by 1977, the Z1 had evolved into the Z1000A1 — better known as the KZ1000 here in the States. The 1015cc machine made 90 horsepower, and has been called the “Grandfather of the Modern Superbike.”
“While the 900 is considered the start of the Z line, its bigger brother is really recognised as the start of a new breed of superbike.” —Timeless 2 Wheels
In Cycle World‘s testing, the KZ1000 ran the quarter-mile 12.19 seconds at 107.65 mph — half a second quicker than the Z1, and 1.3 seconds faster than the Honda CB750F! Reg Pridmore would win the 1977 and 1978 AMA Superbike Championship on a KZ1000, and legends Freddie Spencer and Eddie Lawson would continue winning on the mighty KZ into the early 1980s. Suffice to say, the KZ1000 was — and remains — a legend on two wheels.
Enter our new friend Roy Welton, whose first bike was a Triumph Tiger Cub with a Villiers 197 engine, which he entered into classic trials competition at 10 years old…and became hooked on two wheels.
“Since then, I’ve repaired, rebuilt, and modified trials, motocross, and road bikes, of which I have had so many I have lost count. The Kawasaki was always an idea I had, which was mainly done in my small workshop garage in Mallorca, Spain.”
That Kawasaki is a 1977 Z1000A1, the first year of the model, and this one is the genuine article, with the original frame and engine. Roy recently completed a complete nut-and-bolt rebuild of the bike, resto-modding it with an arsenal of upgraded components.
The engine was rebuilt, and “Project Z” received an electronic ignition, Dyna coils, Z1 4-into-4 exhaust, custom wheels and tail section, Z1 bodywork, Suzuki GSX-R1100 front forks, Öhlins rear suspension, and more. In true restomod fashion, the bike looks almost original at first glance, but a double-take reveals the upgraded suspension, brakes, lighting, and more. Roy says the bike rides as well as it looks, and he couldn’t be happier with the outcome:
“I am really proud and happy with the complete build; it has come out better than I had imagined.”
Below, we talk to Roy for more details on the build.
Kawasaki Z1000A1 Restomod: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
I have had motorcycles since I was 10 years old, starting with a Triumph Tiger Cub with a Villiers 197 engine, which I entered in a classic trials competition, and that’s when my passion for motorbikes started. Since then, I’ve repaired, rebuilt, and modified trials, motocross, and road bikes, of which I have had so many I have lost count. The Kawasaki was always an idea I had, which was mainly done in my small workshop garage in Mallorca, Spain.
• What’s the make, model, and year of the bike?
Kawasaki Z1000A1 1977.
• Please tell us about the bike and custom work involved.
This is a genuine original engine and frame bike, which has just undergone a full nut and bolt conversion / rebuild. Complete engine professional rebuild, clean, and casings polished. New wiring loom, electronic ignition, Dyna coils. New Z1 900 exhausts 4-into-4.
Custom wheels: Akront front 18 x 3.50 with Dunlop Sport max tyres 120/70 ZR 18, and Akront rear 18 x 5.75 with Dunlop Sport max 180/55 ZR 18.
Rear tail tidy, 530 chain and sprockets conversion, custom swingarm, custom footrests.
Z1 900 tank and rear tail section, painted by Dream Machine UK.
Suzuki GSX-R1100 front forks, complete brake and forks rebuild, new discs, LSL bars and grips, custom seat, carbs rebuilt, Kellerman LED indicators, and many more parts to mention. The bike is truly amazing and immaculate, and rides like a dream.
• Can you tell us what it’s like to ride?
It rides amazingly smooth with good power delivery — holds the road and handles really well.
• Was there anything done during this build that you are particularly proud of?
I am really proud and happy with the complete build; it has come out better than I had imagined. Special thanks to Z Power UK, who gave me a lot of advice and help and supplied most of the new ancillary parts.