Ducati 900SS

History

Miglia di Imola, 1972

Modern Ducati, as well as the Super Sport can be traced back to April 1972 when Ducati won the Imola 200 (the European equivalent of the Daytona 200) with a for-production based 750 cc, desmodromic valve v-twin motor developed by Fabio Taglioni. Imola was a traditionally fast circuit that placed a premium on high-speed handling rather than brute horsepower. The Super Sport prototypes used for the inaugural race were developed using a 750 GT based engine and frame and earned instant fame when legendary racer Paul Smart and Bruno Spaggiari finished first and second, respectively, immediately elevating Ducati from a company known for "quaintly individual" motorcycles and into the superbike market.
Super Sport Prototype

The first official Super Sport prototypes used the 750 Sport and 750 GT models for their basis, but featured bodywork styled along the lines of the Imola bikes. The frame was painted blue while the fiberglass gas tank, covers and top half of the fairing were silver. The gas tank also featured a unique translucent strip to be able to quickly see the fuel level.

1974 Super Sport

1974 marked the first year of mass production of Super Sport. The bike featured 10.5:1 compression ratio, a voluminous 6 gallon gas tank and a claimed weight of 333 lb (151 kg). A mere 401 1974 Super Sports were produced and the bike immediately set new standards for production motorcycles and had unique styling, but for all intents and purposes it was a pure production racer with the minimum of concessions to make it street legal. Unfortunately, the complicated bevel gear-driven camshaft made the bike uneconomical to produce, thus the 1974 model is the only round-case 90-degree v-twin with desmodromic valve gear. However the 1974 model bike is considered to be the most significant production bike in Ducati's history, mostly because it offered the highest standards of handling and performance available at that time and essentially saved Ducati from extinction.

1975–1981 Square Case Super Sport

Square Case Ducati Super Sport
900 Supersport

In 1975, two versions of the Super Sport were made available based on the 864 cc "square-case" 90-degree twin cylinder motor; the full 864 cc version coined the 900 and a sleeved down 750. 250 examples of each were produced but the 750 and 900 are virtually identical. The 1975 Super Sport continued to use the right-side gear shift, contradicting the 1974 U.S. regulation that all bikes have the gear shifting on the left side of the engine. Despite this, a handful of right side Super Sports have made it into the United States.

Most of the subsequent changes made to the Super Sport model were to comply with global legislation. Quieter mufflers, relocated shifting and rear brake and new foot pegs. The biggest improvement was the redesign of the kick-starter. On the 1975 model the kick starter would rotate around and shift the transmission into first gear. If the bike was not on the center-stand the rider could potentially have a very unpleasant surprise.

Because the price of the 750 Super Sport was very similar to 900, very few 750s were produced with the majority of them being shipped to Australia, Germany or staying in Italy for racing applications.

By 1978 the bike looked identical, but several significant improvements had made their way into the motor making them more reliable and solving problems with engine cranks breaking. The electronics also improved as well as some minor timing tweaks making the bike run more efficiently. Most notable was a majorly redesigned gear shifter that made the bike a lot easier for owners to live with the bike. Most 1978 900 Super Sports also came with a dual seat and lockable tool box. The solo seat was available as an option. The 1978 model bike is considered to be the finest iteration of the bevel drive square case Super Sports. The 1978 900 and 1979 750s were the last to retain close links with the Imola racers and the last to come with traditional spoke wheels. it was also in 1978 that the Isle of Man TT Formula 1 race was won by a 900 Super Sport, ridden by former World Champion Mike Hailwood in a popular comeback race.[1]

In 1979 the Super Sports were painted black with gold accents to appeal to the British market. Cast Campagnolo wheels replaced the Borrani alloy rims and a Mike Hailwood Replica was made available in very limited numbers painted in lavish green and red schemes. The new changes, specifically the black and gold paint and cast wheels were very successful at making an aging design look more modern. The 1980 model stayed essentially the same with no notable changes. Essentially, the Super Sport was being transitioned into the Mike Hailwood Replica.

Into the early 1980s the fuel tank became less angular and more rounded while the tail section was revised to look more modern with a duck-tail sweep. Side covers were integrated into the tail-section and swoopy paint lines tried to connect the design together. All in all, the early 80s Super Sports were somewhat uninspiring and were met with limited success.

In 1982 the Super Sport was replaced, mostly in name only, by the S2.

YOU CAN HEAR YOURSELF

laughing inside your helmet. It's not a boiling laugh of some rattle-brained loony who's cooking along a high mountain road at 80-plus; it's a laugh of surprise and delight from someone who has discovered for the first time, or rediscovered for the hundredth time, how secure and stable and fun a Ducati V-twin can be in its territorial preserve.

When the Ducati in question is a 900cc Super Sport—with desmodromic valve gear, half-fairing, clip-on bars, solo seat and rear-set pegs—the bailiwick is narrow and deep: it's Curve Country, and nowhere else. Forget in-town trolling; any Japanese motorcycle is better than the Desmo there. Pass on freeway riding. Stretched torsos and coiled legs don't make it; besides, the Desmo delivers short jabs to the body through the seat and bars. Showboating at the local drive-in could be dangerous; a Honda six-cylinder will have a higher, or at least wider, profile.

Even Curve Country isn't entirely safe these days. The Japanese have made swift progress in frame and suspension technology, and Suzuki has been getting close to the heart of Ducati territory. Still, Japanese motorcycles are wide-spectrum motorcycles; a GS1000 must have an electric starter and all those other components that make for civilized riding. The Desmo has no pretense as a Do-Everything motorcycle. Comfort? Convenience? No way. In order to work well, the Ducati Desmo can't afford another 75 or 100 pounds.

To be sure, some one-liter Japanese motorcycles make the Super Sport's quarter-mile performance seem unimpressive. For that matter, both the Honda 750F and Suzuki 750 fours will leave the 900SS about two-tenths behind in a quarter-mile sprint. But mountain roads know nothing of drag strips. Without shifting gears or screaming the engine, the Desmo will rush out of corners with the same steady, implacable, thunderous torque of an Ohio State backfield. Like a superb fullback, the Ducati can do more than power straight ahead; it can stop, cut-and-spin, change pace and direction, and run free and hard.

However limited the Ducati Desmo's territory, that special preserve still exists in 1978. At its vital center the Desmo's attraction is simple: it's easy to go fast on the Ducati, and going fast on winding roads is fun. If someone doesn't enjoy riding briskly on such terms, he will never understand the Ducati and should not trouble himself to own one.

By no means do you have to be an expert-level rider to appreciate the Desmo. The Ducati faithful will probably be aghast to learn that an expert-caliber racer can wheel the latest 550- to 600-pound Japanese Superbikes point-to-point across a mountain range more quickly than a 900SS. If a GS1000 Suzuki has ground-clearance problems, he will work around it; if a Honda six-cylinder weighs in at 600 pounds, he can cope. His ability to deal with disconcerting behavior far surpasses those of a normal street rider. On the other hand, Mr. Average Funday Brisker can ride the Ducati point-to-point more quickly than a super-power multi. On board the Ducati, Mr. Funday's threshold of terror will be elevated to a higher road speed. The distance between Real Speed and Big-Trouble Speed will open up. He'll be going faster and still feel safer, more confident and more relaxed. And he'll be laughing hard inside his helmet. Cycle has not examined the Desmo Super Sport since 1974; at that time the bike was a pure 750cc sports motorcycle with monster 40mm carburetors and booming exhausts. It had a gorgeous tank, rounded in purposeful curves and built with some of the worst fiberglass known to man.

The motorcycle was unencumbered by directional signals or other dead-weight devices; the control switches belonged to the Italian school of Grand-Turismo-High-Tack. The ignition points could present a day-long challenge to those who took ignition timing seriously, and the front Scarab master cylinder and calipers were far below the Lockheed standard. The paint was dusty silver and institutional aquamarine. Assuming you didn't like the silvery color, you merely left the motorcycle out in the sun and the color would change to a pale olive drab. Of course, the fade-down was unequal and inconsistent. But what the hell, it was still the best sporting street motorcycle money could buy in 1974.

Changes come slowjy in Italy; but if you wait long enough, substantial changes will occur. The 1978 Ducati Super Sport is a far more presentable motorcycle than its 750cc forerunner. The paintwork has risen to an acceptable level, and the new blue-and-silver scheme is quite handsome, though the stripes on the front fender, tank, and seat still don't align properly. The windscreen has a protective molding on its trailing edge, and the fairing has been notched in the handlebar area to make room for the federally mandated directional signals. New control switches are light years ahead of the old ones; the ignition key has been moved to the instrument console; and a steel tank replaces the fiberglass creation of the 750. Those who savor the patina of real Italian fiberglass should not get teary-eyed; the fenders, fairing, side-panels and seat are glass, though the stuff is far better crafted than some of the early 750 components.

Significant changes have been made in Ducati V-twin Desmos. From the top, the bore has been increased from 80mm to 86mm, jumping the actual displacement of the 900-series engine to 864cc.

The factory still builds a square-cased 750cc Super Sport, and both the 750 and 900 have identical valve timing: inlet valves open at 63 degrees BTC and close 83 degrees ABC, while the exhaust opens at 80 degrees before bottom center and 58 degrees after top center. There's nothing all that remarkable in the timing figures; more notable is the fact that the valves are both opened and closed by mechanical means.

Fairly conventional-looking rocker arms open the valves, while very curious-looking rockers with forked ends close the valves by lifting up against special valve collars. The rocker arms operating a given valve move up and down together in lock-step unison. Sitting atop the valve is a winkler cap, and by varying the thickness of the valve caps, the proper clearance can be obtained.

The closing valve collars look like small, hollow top hats. Consequently they can be slipped over the end of the valve and down the stem, brim-end first, once the winkler cap is pulled off the valve. This closing collar locks to the valve with normal half-circle hardened wire keepers which fit into a groove on the valve stem and another groove near the uppermost edge of the top-hat collar. The closing rocker adjustment—the distance between the closing rocker fork and the bottom of the brim—must be nil-to-0.002-inch when the valve is on its seat. Since the brims of the top-hat adjusters have different thicknesses, the distance between rocker and brim can be brought within tolerances.

To make sure that the valve closes-even if the adjustment has become far too loose—the closing rocker arm has an auxiliary spring to close the valve, so that the engine can be started. Otherwise there would be little compression in the combustion chamber, because the charge would leak past the valves. And starting an engine with near-zero compression is hopeless. At running speeds, the auxiliary springs are far too weak to have any effect.

Precise adjustment is crucial in a Desmo. Should the clearances be far too great, then there's some risk of losing the keepers, battering the closing adjuster, losing compression and burning the valves. Should the tolerances be insufficient, then the rocker arms can bind, chew up the rocker shoes, and eat the camshaft lobes.

Adjusting the desmo mechanism can be done without removing the cylinder heads from the bike, but the operation remains a real time-consumer in any case. One Great Truth in all this desmo-adjusting business is that the shim you need is never the shim you have. The caps and collars can be worked—within reasonably small tolerances—by using stones or abrasive paper in order to get the proper tolerances. This assumes that you have a system or fixture to keep the working surfaces flat and true.

We suspect that most Desmo owners, though they are attracted to the idea of setting the valves themselves, probably leave the task to some trustworthy person. Some owners may convince themselves that the system, once set at the factory, never needs readjustment. That's simply not true. Experience at Cycle suggests that a new Desmo should be checked immediately, even before beginning the break-in process. Once the engine is run-in, and the desmo system properly clearanced, under normal circumstances the valve gear should be checked every 750 miles, though actual adjustment may not be needed for more than 1000 miles.

Whatever the traditional arguments may be for a desmo system, such as drop-proof/crash-proof valves in a high-rpm engine, more practical considerations likely propelled Ducati toward the peculiar valve gear. First, Ducati has long experience with a desmo system; it's easier to get performance through familiar means than pursuing other avenues. Second, the cramped cylinder heads do not lend themselves to contemporary high-technology valve-spring systems, but this becomes a chicken-and-egg argument. It's likely that the cylinder heads are cramped because Ducati had the option to do a desmo performance system; another factory might have designed the heads to take advantage of the latest in springs and cams technology.

Because Ducati cylinder heads are built in such a way that only fairly short valve springs can be accommodated, there just isn't room for relatively long valve springs which could provide reasonable seat pressure, accurate valve control, and generous lift. Radical camshafts, bat-tressed by 9000-rpm-type springs, can raise hell with Ducati valve guides. The valve guides in the Ducati 750/900 series cylinder heads are short and not especially well supported. Most of the time, this presents no problem for normal valve-spring Ducatis. But high-performance cams and heavy-duty valve springs can wear out valve guides prematurely.

What's really new on the 900 Desmo is a long way from the showy valve gear. Downstairs, there's a new crankshaft assembly. The connecting rods do not appear as blocky as the original 750SS rods because the current rods carry 20mm wrist pins rathefoan the 22mm pins found in early 75Qs Ducatis. The central timing gear drove the bevel gears for each camshaft as well as the ignition points drive-gear.

The 900 utilizes a different system because the oil filter now occupies the area that formerly housed the ignition points. In the 900 engine there's a support plate immediately outside the towershaft bevel gears. The crankshaft drives a straight-cut pinion gear which in turn moves two larger straight-cut gears, one on each side of the pinion, and ball bearings in the plate support the outboard ends of the crankshaft and the shafts on which the two driven gears turn. On their respective shafts these two driven gears key directly on their shafts to helical-cut bevel gears which then anpaps their match-mates that turn the towershafts. The whirring gearsets in the 900 series are simply better supported than the 750 predecessors, and though we didn't investigate first-hand—reshimming the 900 gear-chest would be less a hassle than the early 750s. Finally, outside the support plate at the far end of the crankshaft, a permanent magnet rotor for the 200-watt affernator can be found.

On the left end of the crankshaft there's the familiar helical-cut primary gear, under which is the Ducati version of the magnetically triggered ignition system. The timing is sej at the factory (35 degrees BTC) and further adjustment isn't necessary. Although Italian electrics are often considered inferior, and although early Ducati electronic ignitions had their share of problems, these latest units have a good record. There's a fair amount of energy available, witness the 0.032-inch gap specified for the plugs. More persuasive testimony comes from the racetrack, where those who have compared high-energy battery/coil systems and the electronic CDI unit could determine no difference in straightaway speeds or lap times after switching ignitions.

The 32mm Dell'Orto carburetors draw air through metal filter-boxes with dry felt elements; pleated rubber hoses connect with the carburetors. Old Ducati Super Sports dealt with the atmosphere directly through gigantic intake trumpets which were effective but dirty. In truth, the fibrous felt elements on the 900 are underwhelming; the naked eye can see daylight through the fiber. The Italian filters are better than drawing dust and floating debris straight into the carburetors, though were the 900SS ours, we would opt for American accessory filters.

In order to meet federal regulations, Ducati has fit 32mm carburetors and LaFranconi mufflers to Super Sports destined for American highways. Current 900SS models have been sanitized in yet another way: the crankcase breathes into a molded plastic chamber, mounted under the seat, via a plastic hose; another hose leads out of the chamber and forward into the front air cleaner box. Gone are the days of the Ducati 750SS and its direct and open crankcase ventilation to the atmosphere.

The frame has been carried over directly from the earlier Super Sport. To be brake systems and other items has been changed and improved, but the fundamental frame—the running gear that made Ducati famous for handling—remains the same. When Ducati introduced the square-cased 860/900 series three years ago, the running gear was redone. The new frame was characterized by a swing-arm pivot mounted in eccentrics that provided for chain adjustment and by front downtubes that were mashed flat at the engine mounting points. There were other differences, including revised tube-work in the steering head area; but despite the changes, the Ducati handling survived. The Super Sport frame is the original running gear, and we suspect it's lighter, stronger, and blessed with finer touches than the now-standard Ducati 860 piece.

While the Ducati Super Sport is light, its frame is not. The Italians build frames out of stuff suitable for water pipe, and that's a good thing. Too many motorcycles do too much skimping on tubes, and the result are frames that bend too readily and produce handling that's all too rubbery. The Ducati frame, which uses the crankcase as a stressed member, ties the steering head and swing-arm pivot together rigidly. The swing-arm pivot pin has an outside diameter measuring 29 millimeters, and it rides snugly in the swing arm's bronze bushings. It's quite unlike some Japanese motorcycles with 14mm pivot pins and plastic bushings—and so much slop in the mounting that the swing arm can be laterally deflected by hand at the rear axle. The main tubes of the Ducati swing arm are 40mm in outside diameter, and the wall thickness is 2.5 millimeters.

There's nothing outrageously trick about the Ducati chassis. It's simply an excellent design that's executed with materials equal to the task, and then some.

While it's true that horsepower and weight are the enemies of good handling, the 900SS has enough horsepower to make most chassis get weird—if they were going to. But the Ducati Super Sport chassis, to the staff's certain knowledge at Cycle, can withstand a 90-plus horsepower engine without producing funny handling characteristics.

Ducati is beginning to lag behind the times in the suspension department. Mar-zocchi rear shocks with limp-wrist damping have never been our favorites, and it's a tribute to the chassis that the bike handles as well as it does with the stock pieces. Under some circumstances you can hit an ugly bump in a corner and have the clip-ons slap side-to-side once or twice before going dead center again.

The Marzocchi front fork, with its massive 38mm tubes, offers less room for complaint. It lacks the versatility of the GS1000's air fork or the stiction-free operation of the Yamaha XS11 fork. Still, there's been progress; the 900SS fork works better on the street, thanks to softer springing, than the first 750SS Marzoc-chis. For racing purposes you can't quarrel with the front end, once its setup reflects the preferences of an individual rider. The rear shocks, on the other hand, should be replaced with premium grade units suitable for racing.

Since the frame and swing arm rank in the Forrestal class for strength, Ducati could afford to soften the suspension springing for street riding. Assuming the bike had first-rate damping, there would be no great degradation in mountain road handling, and real gains in ride comfort. In any event, the comfort index isn't an important consideration on the clip-on/rear-set equipped Desmo anyway. Customers buy a Desmo because they intend to go production racing, or because they want to look like they intend to go racing, or because they want a very light, short-range high-performance roadster.

As a serious motorcycle for production racing, the Super Sport does not have the Campagnola magnesium wheels fitted to the style-king of Ducatis, the electric-start Darmah. Ducati has an explanation for this strange situation. Rim width is a matter of rider choice, specific tire requirements, type of racing, and rules of the sanctioning organization. You might need different rim widths for an AMA Superbike Production event at Daytona than those required for a 24-hour club event on a slow, tight circuit. It's far less expensive to change the stock 2.15-inch rims than to buy a whole new set of wheels and shelve the street-going Campagnolas. Nonetheless, serious racers will be fitting magnesium rims to the Desmo, WM3s or WM4s on the front, and WM5s or WM6s on the rear of the bike.

Whether used on the street or on the track, the Brembo disc brakes are impressive. The first generation of Italian disc brakes (specifically Scarab calipers and master cylinders) were spotty in quality, but the latest Italian equipment, Brembo in particular, is very good indeed. Of course, a manufacturer can foul up any brake by specifying inappropriate material or the wrong master-cylinder piston size, but Ducati has got it right. The Brem-bos provide strong, progressive retardation without any spongy softness.

When the rider clamps the binders on hard, he must brace himself with his arms and try to dig his knees into the steel tank; otherwise he and his belt buckle could take a trip up the gas tank. Compared to the old fiberglass tank, the 900SS steel tank is sleeker and certainly safer (it doesn't leak), but the new tank doesn't look as mean and purposeful as its predecessor. Functionally, the new tank has one drawback: there are no recesses in the area of the clip-ons, so it's impossible for some riders to pull the bars back far enough back to take the twist out of their wrists. But given the uncomfortable riding position, and the hard-edged seat, who'll notice an extra little contortion?

On other fronts, street riding has never been so civilized on a Desmo. The ignition key has been moved up to the control console that's now complete with winkers and blinkers. On the left handlebar, a black box (literally) operates lights, horn and directional signals. If you thought all those twinky Italian switches were history, you have only to look to the right bar to find one still in business. And old-timey-Italian switch—a first cousin to the traditional horn/dimmer apparatus—serves as an emergency on/off switch.

In its street-legal trim, the Ducati 900SS provides 12-second street performance. That's more than a second away from the newest one-liter Japanese bikes, but Ducati has never been the straight-line champion of Superbikes. On a road that insists upon dodging left and right, for most people the differences between an 11-second and 12-second motorcycle tend to blur, and other considerations, such as light weight, low-end responsiveness and rock-steady handling become far more important.

The Michelin tires fitted to our test bike were not PZ2-compound tires; those are illegal for street use. The test-bike Michelins may stick better than the Metzelers we've encountered on Desmos before though it's difficult to say without making a back-to-back comparison. Suffice to say that the Desmo is likely to run out of Ground Clearance, particularly on the right side, before the tires run out of adhesion. The low-routing of the exhaust pipes has always been a problem. While exhaust headers with more Ground Clearance could be built, sneak-and-dodge pipes would be more expensive. High pipes, however racy-looking, aren't practical for everyday street use.

Since Ducati offers an optional $400 production-racing kit comprised of 40mm carburetors with cables and manifolds, Conti mufflers and a 36-tooth rear sprocket, a high-road exhaust system is a logical next step. In kitted form the quarter-mile dropped to 12.4 seconds with a terminal speed of 109. That's a half-second quicker and 4.5 mph faster than the street-legal version.

Running the kit on the street makes no sense. The engine has no protection against dirt, the exhaust is noisy, and the increased straightline performance isn't enough to go hunting for certain one-liter Japanese motorcycles. We imagine that most Desmo owners will have to have a kit, just to have it—in spite of the price tag.

Playing by the numbers, you could talk yourself right out of a Desmo. You can buy better quarter-miles figures for a lot less. The Super Sport is a monoposto machine, while Honda's six-cylinder and Suzuki's GS1000 provide for two. While these Japanese motorcycles have 10 cylinders and 32 valves between them, they still don't present service personnel with the chore of desmodromic valve adjustment. There are more dealers for Honda and Suzuki than Ducati, and therefore more knowledgeable mechanics. That's a consideration when you must find the man among men to trust with your shims and winkler caps. Indisputably, the 1000cc Japanese bikes are better finished, with more attention to detail, than the Super Sport. The Honda six-cylinder even has more Ground Clearance than the Desmo.

Ironically, in these days when dealers regard a test ride as something bordering on moral perversion, the only way for anyone to know whether he's Desmo material is to ride one. Frankly, a lot of people will ride the Desmo, and they will find it an interesting novelty, and nothing more. Others will cruise it around the block, trying to outmuscle the Desmo's in-town truckiness and heavy handling. Still others will sample roads that travel uphill and downhill like a sidewinding rattler. They will sense the Ducati's stability, feel its agility, marvel at its almost hydraulic power—and come back laughing as only a True Believer can.

Source Cycle 1978