Five of the best Zeds

Kawasaki Zeds were the biggest, fastest, baddest inline fours of their day. 40 years on they should all be cossetted classics, but Zed aficionados continue to make them faster still

hen Kawasaki’s Z1 first emerged in 1972 it started a craze like nothing seen before it. It was the fastest production machine of its generation and the Yanks quickly dubbed it ‘The King’,  a title it held firmly in its grasp for the bulk of the ’70s, until the second generation – the 1000J, 1100R, Z1-R and GPz1100 led the way in the early ’80s.

The strength of the standard engine (a simple air-cooled, dohc, 8v, fundamentally unchanged from Z1 to GPz) meant massive increases in power could be achieved without harm, while success on the track all over the globe led to a raft of aftermarket goodies.  

Unfortunately the early Zed’s chassis didn’t match their engine’s stunning performance – only getting close by the time the GPz1100-B1 appeared in ’81 – so frame modification became as much part of the Zed cult as engine tuning. 

But when they were sorted few other bikes could match a fettled Zed. Kiwi loony Graeme Crosby and young Aussie Wayne Gardner took on exotic GP and TT-F1 bikes aboard their Moriwaki Z1000s back in the late’70s and early’80s and won.

On the other side of the pond Rob Muzzy made stars of rising talents Eddie Lawson and Wayne Rainey aboard his ferociously fast Kawasaki production racers.

Interest in modified Zeds has never diminished, and if anything it’s getting stronger. Here are five of the UK’s best modified Zeds to prove it.

 

1. The supercharged one

Rob Meggitt has built a number of modified Zeds (see his ride to work Z1-R on p27) and this is his wildest Kwak to date.

Yes, that is a supercharger bolted to the right hand side of this 1978 Z1000-A2. Rob found the ultra rare Drouin unit on eBay. Its performance and aesthetics dominate the bike. 

“First time I rode it and let it go for real it fried the clutch, wheelspun and tried to throw me off all at the same time. It revs like a two-stroke and sounds awesome. Every part of it is my work except the paintjob, with lots of time spent hand building brackets and fittings to create the bike.” 

Rob reckons that the supercharger can unleash a potential 180bhp; not at all bad for a 32-year-old air-cooled, eight-valve four. 

“It’s hard to change gear fast enough to keep up with the engine, it accelerates and revs up that quickly, but there’s still plenty more to come.

“Originally it would have been fed by a 55mm injector but it didn’t come with that so, at present, it’s got a 45mm Keihin ‘pumper’ carb fuelling it. It keeps hitting a wall before it fully revs out because there’s not enough fuel getting through.

At least Rob’s frame bracing is able to handle the clout of the  ’charger. “Handling is now like a modern bike. The tube work handles the power with ease.” 

Rob Meggitt

Year/model 1978/Z1000-A2

Year acquired 2007   

Project time 2½ years

Favourite part? “Each part has been a project in itself so it’s hard to choose, but I do like the handmade filler cap and the urgency of the power delivery”

What’s it like? “The chassis is taut, it handles well with updated running gear and goes like stink thanks to the Drouin supercharger”

 

ENGINE 

Type air-cooled, dohc, 8v inline four

Capacity 1075cc

Tune  Kawasaki GPz1100 head, eight-plug mod

Rods  standard; welded crank

Pistons  Wiseco

Clutch  standard clutch, hydraulic conversion

Gearbox standard

Fuel system  Drouin supercharger

Air filter  homemade wire mesh

Exhaust  homemade with Ducati end can

Ignition Dyna ignition with four Dyna coils to feed the eight-plug cylinder head

 

CHASSIS 

Frame 1978 Z1000-A2, braced with modified shock mounts 

Front forks Kawasaki ZX-9R

Rear suspension Yamaha XJR1300SP swingarm with Suzuki GSX1400 shocks

Wheels Kawasaki ZX-7R

Front brakes 2 x 320mm discs, Suzuki GSX-R750 SRAD four-piston calipers

Rear brake 1 x 230mm disc, Suzuki GSX-R750 SRAD two-piston caliper

Tyres  Maxxis Permaxx 120/70  17, 180/55  17

 

PERFORMANCE 

Max power 180bhp plus

Top speed 175mph

Estimated value £10,000

2. The one with the Harris frame

Barry Swailes’ Harris Magnum Z1000 is something of a chameleon, having evolved and changed its spec countless times over the years.  

In fact it’s still not ‘finished’, and Barry says he’s “still on with development”. When he bought it back in 1987 it featured standard Z1000 running gear and was in need of some serious attention. Its latest incarnation with GSX-R750 forks, trick lightweight Marchesini wheels and the gorgeous Japanese-built Midnight 4-1 pipe (a Moriwaki copy) came about courtesy of a sheep.

“I hit one at 100mph, and it needed a complete rebuild after that. But I’m pretty happy with it now,” says development engineer Barry, “It’s had many transformations over the years with many variations of forks and rear ends fitted in search of that winning formula.

“It’s geared for sensible road use; so not a massively high top speed but good usable acceleration and sweet handling.”

Barry Swailes

Year/model  1986/Harris Magnum 2 Z1000 MkII

Year acquired 1987 

Project time Barry’s still on with
the development

Favourite part of bike “I just love the way it looks”

What’s it like “It’s pretty sharp and focused for the road, but still great fun to ride”

 

ENGINE   

Type air-cooled, dohc, 8v inline four

Capacity 1075cc

Tune standard

Rods standard

Pistons Wiseco 

Clutch standard

Gearbox standard

Carbs Mikuni 36mm RS flatslides

Induction Ramair foam filter

Exhaust Japanese-built Midnight 4-1 (Moriwaki copy)

Ignition Dyna S

 

CHASSIS

Frame Harris Magnum 2

Front forks Suzuki GSX-R750L

Rear suspension Harris monoshock/WP shock

Wheels  Marchesini 

Front brakes  320mm PFM discs, six-piston AP Lockheed calipers

Rear brake  220mm Spondon disc, two-piston AP Lockheed caliper

Tyres Pirelli Diablo 120/70 17, 190/50 17

 

PERFORMANCE 

Max power 120bhp

Top speed 125mph

Estimated value £6500

 

3. The turbo one

From a distance Steve Cundall’s GPz1100-B1 looks fairly stock. But get up close and it becomes clear it’s anything but. And that’s a big part of its obvious appeal.  

Steve’s owned his GPz for 26 years and deciding to turn it into something special after the engine lunched itself in a major way.

“It was bog standard at the time,” remembers Steve, “I was out racing my mate’s GSX1100 one day and the Zed jumped out of gear at 140mph. The top end destroyed itself and it was cheaper to buy a big-bore kit than repair it with genuine Kawasaki parts. That was the start of it all really, and the project just grew from there with many variations of running gear and engine set-ups before I settled on the Rajay turbo. I had twin 40mm Webers on it at one point, but it returned just 13mpg, so I couldn’t afford to run it in that configuration.

“I have a standard GPz1100 too, which offers an interesting comparison. Recent dyno runs show 130bhp at 6lb boost, and 220bhp at 12lb.
I leave it at the lower level of boost as it’s oil-tight and running well at the moment.”

Steve Cundall 

Year/model 1981/GPz1100-B1 

Year acquired 1984

Project time 26 years

Favourite part of bike  “Marvic wheels” 

What’s it like  “Much better than standard” 

 

ENGINE 

Type air-cooled, dohc, 8v inline four

Capacity 1170cc

Tune gas-flowed head and turbo-spec cams

Rods standard; welded crank

Pistons Wiseco

Clutch  Cir-Cycle clutch kit

Gearbox  standard

Fuel system Mikuni HSR 45mm carbs/
Rajay turbo

Air filter K&N

Exhaust  Mr Turbo

Ignition  Dyna 2000

 

CHASSIS 

Frame standard GPz1100

Front forks Yamaha YZF750SP

Rear suspension Suzuki GSX-R750 SRAD swingarm, Öhlins shocks

Wheels  Marvic

Front brakes  320mm Spondon discs, two-piston Lockheed calipers

Rear brake 200mm disc, Harris
two-piston caliper 

Tyres Pirelli Diablo 120/70 17, Dunlop D202 170/70  18

 

PERFORMANCE 

Max power 130 bhp@6lb boost (220bhp@12lb boost)

Top speed 150mph

Estimated value £4000

 

4. The one that arrived in boxes

Neil Scott’s Z1000J came into his life 13 years ago in boxes as someone else’s unfinished project. 

“It arrived as a standard Z1000 in half a dozen tea chests,” says Neil. “Once together I realised the brakes weren’t good enough and it all started from there, really.” 

Neil wasn’t impressed by the handling either. “It wouldn’t go around corners either, so it was only a matter of time before it hurt me. I uprated the brakes first, but every time I improved something on it that just highlighted something else that needed attention.”

The front end has been uprated with Honda FireBlade wheels, brakes and forks, while the  rear end is now controlled by a beefy Metmachex swingarm and Öhlins shocks.

“It now goes, stops and goes around corners well too. I couldn’t have done it without the help of my uncle Colin who made many of the parts.”

 

Neil Scott

Year/model 1981/Z1000J

Year acquired 1997 

Project time still in progress

Favourite part of bike  “Every bit”

What’s it like “It’s fast, it stops and starts every time, I just love it” 

 

ENGINE 

Type air-cooled, dohc, 8v inline four

Capacity 1170cc

Tune standard

Rods standard

Pistons Wiseco

Clutch standard

Gearbox standard

Carbs Mikuni 38mm RS flatslides,
ex-Suzuki GSX-R1100

Induction  K&N

Exhaust custom built underseat stainless system 

Ignition Dyna S

 

CHASSIS 

Frame standard Z1000J

Front forks 1994 Honda FireBlade

Rear suspension  Metmachex swingarm, Öhlins gas shocks

Wheels 1994 Honda FireBlade

Front brakes 300mm Stealth discs, 1994 FireBlade four-piston calipers

Rear brake 220mm Stealth disc, 1994 FireBlade two-piston caliper

Tyres Metzeler Sportec M3  130/70 16,  180/55 17

 

PERFORMANCE 

Max power 122bhp

Top speed 140mph

Estimated value £6500

 

5. The everyday ride

Rob Meggitt likes his bikes to be special; his supercharged Z1000 (p22) is proof of that. So it’s little surprise that even his every day ride is out of the ordinary. 

And this is it – a much modified Z1-R. “I grafted the running gear from a ZXR750 into the braced Z1-R frame,” says Rob, who learned the art of welding when he was just eight. “Every problem – and there are many when building specials – has been sorted by myself.”

The end result is ridden every day because Rob has never passed his car test. It’s fast, super reliable and, above all, fun.”

Rob Meggitt

Year/model  1979 Z1-R

Year acquired 1998

Project time three years 

Favourite part of bike “Home-built belt-driven alternator” 

What’s it like “I ride it to work every day. It rides like a modern bike and handles like a ZXR750”

 

ENGINE 

Type air-cooled, dohc, 8v inline four

Capacity 1075cc

Tune Manzano big-valve race head 

Rods standard

Pistons Wiseco

Clutch standard

Gearbox standard

Carbs Mikuni 32mm roundslide (Suzuki GSX1000S Katana)

Induction homemade mesh filter

Exhaust homemade; Remus end can

Ignition Dyna S

 

CHASSIS 

Frame  modified and braced Z1-R

Front forks  Kawasaki ZXR750 H1

Rear suspension  Kawasaki ZXR H1 swingarm; Hagon shock; NWS linkage

Wheels  Kawasaki ZXR750 H1 front and ZXR750H2 rear 

Front brakes 320mm Kawasaki ZZ-R  discs, Yamaha R1 four-piston calipers 

Rear brake 230mm disc, R1 two-piston caliper

Tyres Maxxis Supermaxx 120/70 17,  180/55 17

 

PERFORMANCE 

Max power 120bhp

Top speed 165mph plus

Estimated value £4500

Words Chris Pearson   Photography Simon Hipperson