Gone With the Wind
HONDA CX650 TURBO vs. YAMAHA SECA 65( URBO vs. KAWASAKI GPz750 TURBO vs. SUZUKI XN85 TURBO
CW COMPARISON
GONE WITH THE WIND
The Great Turbo Era lasted just three years in the early Eighties. Three decades later, we ride four classic Japanese turbo bikes to find out what all the excitement-or lack of it-was about.
PETER EGAN
HISTORY SEEMS TO PROVIDE US WITH A golden age for nearly everything. We had the Golden Age of Greece, the Golden Age of Steam Trains and the virtually unforgettable Golden Age of Disco. I personally attended high school during the Golden Age of Beehive Hairdos and Creepy Church Lady Glasses with Rhinestones on Them.
And the early Eighties, of course, were the Golden Age of Turbocharging. Lots of small "pocket rocket" cars suddenly sprouted these whirring little exhaust-
driven compressors, and between 1982 and 1984, all of the Big Four in Japan introduced turbocharged motorcycles.
Actually, Kawasaki got there a little earlier than that, with the 1978 KZ 1000 Z1 -R TC. But this was a factory-approved bolton of an existing aftermarket turbocharger (see sidebar, p. 39). It went like hell but was soon deemed just a bit hairy for the average man on the street. Or man flat on his back, in some cases. Yes, the thing would wheelie! This fire-breather was dropped from the lineup after only two years.
A brief hush descended over the land, and then, in 1982, Honda and Yamaha suddenly brought forth a pair of the first full-factory purpose-built turbos—the fantastically complex CX500 Turbo and the squarishly futuristic Seca 650 Turbo.
A year later, Kawasaki re-entered the fray with its lightning-quick GPz750 Turbo, Honda upgraded its CX500 Turbo to a CX650 version with more torque and power, and Suzuki jumped in at the last minute with its surprisingly mild XN85.
The next year they were all gone.
No more turbos.
So, what happened?
Well, lots of things. First, the turbos arrived at a time when the Japanese had drastically overproduced their bikes just as the market slowed and Baby Boomers suddenly found themselves running out to buy more Pampers or Gerber's Prune Mush instead of a new motorcycle. Second, it must be said that turbos were just slightly.. .disappointing.
The idea behind turbo bikes was to make light and agile middleweights perform like full-sized superbikes. Trouble was, the turbos were not all that light (or cheap), and the big-displacement Fours were not all that heavy and cumbersome. And they were simpler. Customers compared the Suzuki XN85 with the svelte, race-winning magnificence of the new Suzuki GS1100 and went straight to the checkout counter with the 1100.
Motorcyclists, it seemed, wanted torque—bikes that came off corners hard, with no waiting and no funny midcorner awakenings. Most of the turbos, our road tests pointed out, just didn't feel as good on a curvy road, even if they produced a scintillating top-end rush. We admired the technology of the turbos from afar but didn't feel compelled to buy one, and they went away. Well, they didn't all go away.
Some of them wound up in the spacious warehouse/workshop of our good friend Joe Bortz in suburban Chicago. Bortz has an impressive collection of significant bikes from the Seventies and Eighties, nearly all of them pristine, low-mileage examples. We last saw him in these pages in December, 2009, when he offered us a chance to ride three of his six-cylinder bikes (Honda CBX, Kawasaki KZ1300, Benelli Sei).
While we were there, Bortz said,
"You guys need to take my little collection of Japanese turbos for a ride. They're really neat bikes."
Duly noted, and a good idea. We thought it would be fun to revisit that group of bikes after all these years and see how they feel now. Would they still seem like a technological dead end or offer some virtues we'd missed the first time around? Most of us had ridden only one or two of these bikes in the past, so it would be fun to try them all together.
We massed ourselves chez Bortz— Editor Mark Eloyer, Contributing Editor Steve Anderson and I—on a beautiful and unseasonably warm autumn morning to find out. Joe Bortz's mechanic, Mike McKeon, would be riding the fourth bike. We backed them out of the warehouse, fired up the engines and hit the road. I tried the Honda first.
HONDA
CX650 TURBO
The NASA/computer-age lettering on the CX's side panels says it all about Honda during this era. They were masters of the technical tour de force, pleased to show the world they could conquer any complexity and make it work. And so the turbo got applied to one of their oddest (but most pleasantly charismatic) creations, the asymmetrical-looking, water-cooled, transverse V-Twin known as the CX500.
The fuel-injected CX500 Turbo was a bike that quickly reinforced everyone's worst fears about turbos: tepid bottom end and considerable turbo lag So, Honda boosted the displacement and compression ratio, and turned it into a 650 with heartier low-end grunt. The computer circuitry was also simplified.
And now, on our fine Sunday morning, I fired up the Honda with a touch of the button, backed off on the fast-idle control, and it quickly settled into a nice V-Twin heartbeat.
Light clutch, comfortable seat and a moderate sport-touring riding position. You sit with feet high and just slightly back, knees tucked in behind the fairing and a slight forward lean to the bars. Pleasant wind flow, quiet and smooth.
By the time we'd gone three miles, I felt ready to head for either coast on a long road trip. The Honda feels refined, solid and integrated. Bottom end seems at least as strong as on any naturally aspirated 650 Twin; but around 4000 rpm, the turbo starts to work its magic and speed builds with a satisfying, heady surge to its 9000-rpm redline. If you keep it on boil at around 5000 rpm, it's ready when you are. To sense any turbo lag, you have to hit the throttle hard when it's bumbling along below 4000.
The verdict: very rideable and civilized, with the turbo serving to boost the fun factor and make the best of short passing zones on the highway. Still looks good, too, and the styling hasn't aged as much as it has on some of the others. I ended the day thinking this is a bike I'd love to own.
YAMAHA
SECA 650 TURBO
Climbing off the pristine, almost new (108 miles on the odometer!) Honda, I went straight to the other end of the spectrum, the Seca 650. This example was the highest-mileage bike here, had an oil leak at the turbo seals and was smoking heavily from its left pipe (the right pipe handles waste-gate pressure). Mike the mechanic was muttering heavily about the difficulties of wrenching on the Yamaha, and I believe the phrase "drop it off the Chicago Navy Pier" was used.
Nevertheless, I climbed on it with a positive attitude because I'd actually gone to the introduction of this bike in Japan in 1982 and ridden it extensively around Yamaha's very fast factory test track.
I had a wonderful time trying to catch our basically uncatchable current Senior Editor, Paul Dean, when he was working at Another Magazine. Paul and I ground off a great deal of footpeg and muffler metal and made many colorful sparks. I remember the bike being smooth, fast, good-handling (if a bit softly sprung for track work) and fun to ride, with an aerodynamically serene sport fairing.
This example, of course, was not so new. But even with the turbo smoking like a chimney, the thing got up and moved. At any speed, this bike is much buzzier than the Honda Twin, but it has a moderately flexible bottom end and hits its torque peak (54.2 ft.-lb.) at a reasonable 5000 rpm. From there it zaps itself quite nicely up to its claimed 85 horsepower at 8700 rpm. No slouch, this thing, even in tired condition.
Still, in its day, the 653cc Yamaha was the slowest bike in this group for quarter-mile times, turning in a l2.68-second/106.13-mph run, a tick slower than the Suzuki. Our tested top speed (June, 1982) was 121 mph,
18 mph slower than the blazingly fast Kawasaki. Time has made these differences seem almost academic, however, and the Yamaha still has a nice frenzied kick. Worth noting, it's the only bike here with the turbo pushing air through carburetors (30mm CVs) rather than a fuel-injection system.
Our overall impression is that the Seca hasn't aged quite as gracefully as the others in either styling or durability, but some of this may be a reflection of its deferred-maintenance past. When I rode a new one, nearly three decades ago, it felt sophisticated and nicely finished.
KAWASAKI
GPz750 TURBO
By the time this bike hit the market, Kawasaki had long since established itself as the Horsepower Master of the World, and—as expected—didn't fool around with its late-entry Turbo. It was—and is—clearly the fastest bike here by a good margin, with a measured top speed of 139 mph and a quartermile of 11.40 seconds at 118 mph. The next closest was the Honda, at 11.75 seconds and 112.21 mph. (These are Cycle magazine times, as CW never tested the 650 version of the CX Turbo.)
When you climb aboard the Kawasaki, it feels long, lean and quick; and despite having 20,183 miles on the odometer, this example seemed almost as solid and tight as a showroom-new motorcycle. And nowhere is the Dr. Jekyll & Mr. Hyde aspect of turbo behavior more marked than in the Kawasaki—probably because it's cranking out a claimed 111 hp at 9000 rpm. This thing switches from being a very likeable 750 UJM commuter bike to a Tasmanian devil somewhere between 4500 and 7000 rpm. It isn't dangerously abrupt, but it's one of those, "the faster it goes, the faster it goes" deals, and you do want to hang onto the grips and not be eating a sandwich when it kicks in. Quite thrilling.
The only oddity about the Kawasaki was the steering, which felt odd and twitchy at low speeds, jinking this way and that. Steering-head bearings? Tire wear? Long wheelbase? We didn't mention this in our March, 1984, road test, so it may be one or all of the above.
The chassis on this bike was compliant but taut, and the brakes (borrowed from the GPzl 100) were excellent, with nice linear feedback at the lever. And the seat (as on all these bikes) is excellent. That and an all-day yet sporting riding position make it—like the Honda and Yamaha—a bike you wouldn't mind touring on.
And when the roads got straight and dull out on the Great Plains, you could always twist that throttle to get your heart restarted. As we concluded in our '84 road test, "To the right person, that excitement is worth the price of admission. Still is, even now.
SUZUKI
XN85 TURBO
I got on the XN85, with its clean, Katanalike styling last, and immediately fell in love with the compactness of the bike and the riding position, which is the sportiest of the bunch. To sit on the Suzuki is to wish you were heading out pit row at your favorite circuit. It feels most like a modem 600 sportbike in its dimensions and view over the small fairing.
But then you get on the throttle and are glad you aren't going out pit row. Not to compete with any modern 600s, anyway. Of all the bikes here, the 674cc Suzuki has the least thrilling—and the least turbo-like—acceleration curve. It's actually a little quicker and faster than the Seca 650 Turbo but doesn't feel it.
As Anderson said when he climbed off the bike, "It's hardly a turbo!"
And the bike's owner, Bortz, laughed and chimed in, "It's hardly a 650!"
Anderson, who had just replaced me as Technical Editor at Cycle World when this bike came out, recalls that the American Suzuki folks felt slightly shocked at the placid performance of the final production version because the prototypes in Japan had been so quick. Apparently, Suzuki decided to do the Socially Responsible Thing and dial the boost back a bit. Until it was almost subliminal.
Anyway, the Suzuki is no great thrilling ball of fire, and when you wring the throttle, you simply get linear forward progress. The engine note is slightly harsh and busy, with no euphonious turbo wail.
Other than that, it's a very likeable bike, probably my favorite chassis here in its size, agility and crispness of steering. But power-wise, it's hard to detect any excitement that wouldn't be more vivid in a good old standard, naturally aspirated 750cc Four.
Suzuki got into this game last of all the companies, however, and you can almost feel the sun going down on the turbo era in the tuning of the bike, as if the engineers and marketers might have lost interest in the concept.
Kawasaki, meanwhile, brought down the curtain in 1984 in a blaze of glory, leaving us a bike that's still fast and furious. Honda had left the stage a year earlier, retiring what I feel is the most complete, beautifully styled and impeccably engineered bike in this group.
The Yamaha? Well, we'd need one without a turbo oil leak to make a fair assessment, but I swear it was a wonderful bike to ride around the Yamaha test track in 1982.
Even if I couldn't quite catch Paul Dean.
CONCLUSION
Generally, I would say all these bikes have aged surprisingly well. They do suffer, in varying degrees, from small amounts of turbo lag, but that doesn't seem as important now (at least to me) as it did when I saw every sportbike as a potential AFM or WERA box-stock roadracer. But, taken as road bikes, they still offer a lot of entertainment value. There's something fun about cruising on a comfortable middleweight bike that gets good fuel mileage (these bikes all recorded between 45 and 51 mpg), then moving out to pass and finding yourself beamed into a galactic vortex by a booster rocket. The force you have always with you, just a twist away. □
