Kawasaki Z1R-TC - The Psycho Turbo Z

TURBO. For a certain generation who grew up in a time before forced induction became a “green” thing, nothing screams “Eighties Excess” and “Performance” like a turbocharged… anything. You are probably familiar with the early turbocharged cars that used forced induction as a way to squeeze extra power out of emissions-strangled motors of the Reagan era. Less known is a short-lived generation of production turbo motorcycles from 1982-85. The first shot in the 1980s turbo wars came from Kawasaki, who attempted to revive an ailing model by boosting it beyond all reason. And they beat the other manufacturers to the punch by introducing their turbo fiend at the end of the Disco era.

In the late 70s the Kz1000 was Kawasaki’s bread-and-butter superbike, a ‘litre four-pot brute that competed with the Suzuki GS and Honda CB for dominance on the street and track. It was a direct descendant of the legendary "New York Steak" 903cc Z1, the bike that had knocked the CB750 off its perch in 1972 and cemented Kawasaki’s reputation for high performance engines. Over the 70s the Z was updated gradually, eventually being punched out to 1016cc in the Kz1000, which would beget the Z1R in 1978 through a styling change, cast wheels, and the addition of a headlight fairing.

Unfortunately for Kawasaki in 1977-78 the big-Zee (Zed?) was getting behind the curve and was in dire need of an update. Kawasaki had long been seen as the purveyors of particularly fast, vicious machines that had more motor than frame. The H-series of two-strokes were a good example of the widowmaker reputation earned by Kawasaki sports bikes – monster motor, flexy frame and suspension, mediocre brakes. Go faster than everything else - at your own peril. The Z continued this tradition by stuffing a hot four-cylinder motor into an antiquated chassis, but the competition had caught up in the power department by the late 70s. Handling was always the weakness of the Z models, as period tests often pointed out. Zs were prone to instability and headshaking as well as rubbery handling, and attempts to stiffen the suspension just made the flobbery frame even more apparent. Tire choice was critical, as a set of mismatched profiles could cause serious wobble issues. The Z1R was no better in this respect, being mechanically identical to the Kz1000 - which now had 90 odd hp twisting the beams that were more or less unchanged since the Z1 hit showrooms in ‘73.

So what do you do when your flagship is falling behind the competition and spitting off riders due to an outdated chassis? If your first thought was “give it a shedload more power” then congrats, you are just as insane as circa-1978 Kawasaki USA. And you’d probably be the target demographic for the Z1R-TC, the angriest, most ferocious motherf***er of a superbike to hit the streets in the late 1970s.

The Z1R-TC was remarkably under-engineered and overpowered in just about every respect, and was so ridiculously over-the-top that it is scarcely believable that it was sold through official dealers. In fact it wasn’t really a production model at all, more of a dealer special put together to lure power-mad riders into Kawasaki showrooms in the USA and Canada and shift stocks of the languishing Z1R. It wasn’t the first or last example of the breed – the legendary Laverda Jota 1000 wasn’t a production model, it was a hotted-up 3C built by a British distributor. While the Jota would become mythical, the TC would fade into obscurity. Presumably after laying a big strip of rubber and then promptly melting a piston.

The TC was the result of slapping a turbo kit onto an otherwise standard Z1R. And I do mean slapping on. No internal modifications were made to the motor. No suspension change. No frame reinforcement. Just a turbo kit and about 10 lbs of boost knocking forty extra horsepower to the rear. Yep, the TC was rated for a staggering 130hp, in an era when a Ford 302ci V8 was wheezing out 140 hp on a good day. Power claims vary of course – boost pressure was variable and the wastegate was adjustable, so you could have gotten anything between 6 and 10 psi “as delivered” with the potential to screw boost into “expensive” territory with the flick of a screwdriver.

And it wasn’t just the horsepower tally that impressed, it was the way it made power that was truly breathtaking. By breathtaking I mean it would scare they everloving piss out of you with the most evil turbo lag this side of the ass-engined Porsche 930. Up until 4500-5000 rpm it behaved like a standard KZ. Then all hell would break loose and it would go tearing towards redline with a spurt of violent acceleration. Just like every other early turbo machine, in other words.

How did such an amazing monstrosity ever see the light of day? The TC was the product of a specific set of circumstances that will likely never be seen again. Alan Masek, a former Kawasaki USA general manager who had helped with the original Z1 project, had started a company called the Turbo Cycle Corporation in California to offer American Turbo-Pak bolt-on kits for power-hungry riders. ATP was the go-to for go-fast parts during the golden era of Japanese superbikes, and offered turbo kits for Z1s, CBs, CBXs, and of course KZ/Z1s. Masek made an arrangement with Kawasaki in North America to take stock pastel-blue Z1-Rs, install the ATP kit at TCC, then have the completed “Z1R-TC” sold through Kawa dealers without a warranty. The bike would be a flagship performer that would garner attention for the brand until they were able to replace the ageing KZ, but without the liability headaches that you’d expect from bolting a big ass compressor to bike with an inadequate frame. It would also help to shift some of the unpopular Z1Rs that were stagnating in the showrooms. The bike was technically an aftermarket special produced by TCC, which absolved Kawasaki and the dealers of any warranty claims (and allowed for a lack of compliance with EPA measures…). Buyers were required to sign a legal waiver and forfeit the standard warranty.

The TCC modifications were straightforward. A complete exhaust system with a cylindrical header was connected to a Rajay turbocharger that was situated just behind the engine, where the standard bike’s carburettors sat. An adjustable wastegate metered pressure in the system (which could easily be knocked up with a screw adjuster on the bottom of the ‘gate), which pumped into an inlet manifold running a single 38mm Bendix carburettor fed by a high-flow fuel pump. Finally, a boost gauge was tacked onto the steering head. Price for the completed machine was $5000 USD, vs the Z1-R at $3695.

Aside from the TCC fettling the bike was standard. You got an air-cooled four with double overhead cams and 2 valves per cylinder. Bore and stroke was 70x66mm, compression 8:1. Frame was a steel tube cradle design with Kayaba suspension front and rear. Wheels were cast alloy with cross-drilled disc brakes front and rear. Transmission was a 5 speed with chain final drive. With the turbo plumbing the wet weight was a shade under 560 lbs. The signature Z1R bodywork was retained, and even the paint was left stock aside from the addition of a couple of TC badges on the side panels.

Media test bikes were modified to cope with the boost. Valve and clutch springs were upgraded. The pressed-up crank pins were welded together to prevent crank twist under load. Performance was stunning, - at 10lbs of boost magazines could knock out quarter miles in the high 10s at over 120 mph. It was scarcely believable at the time. Don’t forget that this kind of performance was in a bike that was known to have poor handling and braking, now made even more interesting with the addition of a ridiculous spike of power at the top of the rev range. 

A problem for real-world owners was that those reinforcements made on test bikes were extra-cost options on the “production” models. In addition to internal strengthening the compression ratio should have been lowered, and the ignition retarded, to prevent detonation and piston ring failure. Owners quickly found out why they had to waive their warranties. Running anything over mild boost would shatter rings and melt pistons in short order (sometimes as little as a few hundred miles!). If you missed a shift and over revved, easy to do when the boost came on hard at 7000 rpm before the 8500 redline, you’d get valve float and smash the pistons into the valves. And that’s if the crank didn’t twist or spin a rod bearing under the extra load.

Just makes you want to ride one even more, doesn’t it? 

The 1978 TC earned a reputation as a fearsome, barely controllable brute that was king of the quarter mile. Just the sort of reputation that sells bikes – motorcyclists have always been a weird lot of madmen, and when you tell them something is just “too fast” and brutal you can be sure they will be lining up to buy it.  Of course some of the legend is just that - legend. "My best friend's third cousin's uncle got this turbo bike that will do 200 miles per hour and power wheelie in 5th gear. It's a secret prototype you won't find in the catalogues because its too fast, he bought it right from the factory. Swear to god guys, it's the truth."

250 of the original powder-blue models were made with moderate success; sales would improve in 1979 with the introduction of the TC2. This is the most recognizable TC, with black paint set off by striking Molly Design neon graphics that make it look like a turbocharged surfboard. ’79s were still based on ’78 Z1-Rs (including a few unsold TCs) as Kawasaki had discontinued the slow-selling model that year. The TC2 incorporated a better 4-1 header, improved lubrication, and a milder 6 psi boost setting (still adjustable by the owner for maximum grenade potential, though). Turbo lag was reduced, as was overall power, but reliability was improved. The proper internal reinforcements for any sort of longevity were still optional.

250 TC2s were made before California laws changed and the party ended. From 1980 on no production vehicle could be sold with exhaust modifications, so the TC became verboten. Shame too, because sales were picking up in 1979 as the legend grew. It wouldn’t be until 1982 that another production turbo bike would be available, when the legendarily ugly but well engineered Honda CX500 Turbo “Plastic Maggot” hit the market. It would be followed by a short trend towards turbocharged middleweights - which would all be discontinued by 1985 due to high cost, high complexity, and insurance blacklisting. The Z1R-TC beat them all to market, and trumped the later bikes for outright performance (at the expense of any form of longevity). The TC has become a rare collectible; with only 500 examples in the US and Canada, and with a reputation as a violent street brawling brute, it’s little wonder than Z1R-TC values are rising steadily and available bikes are getting snapped up by enthusiasts “in the know” about Kawasaki’s off-the-record psychotic turbo bike. It's the truth guys, my aunt's boyfriend's half brother's best friend said so.                   

Interesting Links and Image Sources
Some awesome period images of a 1979 TC2
Molly Designs California
Motorcycle Classics on the Z1R-TC
A 1979 TC2 for sale 
A curious rant from someone who claims to have had all the "correct" info about the TC in a stockpile of documents which he destroyed because no one offered to buy them