OVERSHADOWED


Kawasaki ZX-11 Ninja vs. Vincent Black Shadow
The fastest motorcycle in the world meets its match

vincent
By: Andy Saunders
What's the link between a 1952 Vincent Black Shadow and a 1993 Kawasaki ZX-11? Until the ZX-11's illustrious ancestor, the Z1, came along in 1973, the Vincent was still the fastest production motorcycle in the world, even though production had ended in 1955. Over the last four decades, myths and legends have grown around the Vincent. People say the Vincent is "as torquey as a locomotive", that it "lasts forever" and that it's "the fastest thing on two wheels." Some of these legends are true. In a roll-on contest from 30 mph in top gear (when both bikes are revving at less than 2000 rpm) the Vincent still pulls away. Even at 50 mph it's close.

At first sight, the ZX-11 has about as much in common with the Vincent Black Shadow as an F-117 has with a P-51D. But there's more to it than that. Both of these motorcycles have long pedigrees; the Kawasaki descends from the original 1973 Z1 model, via the KZ1000 and have added water cooling and a fairing. By 1952, the Vincent also had 20 years of development behind it, plus the work of a pair of brilliant engineers.

Phillip Vincent built his first production motorcycle in 1929, under the HRD banner. Eventually, the HRD name was dropped to end confusion with Harley-Davidson. The engine was an unremarkable J.A.P. single, but Vincent's first motorcycle, and every one thereafter, used an innovative rear-suspension system, similar to a monoshock (in 1955, he introduced a true monoshock on the fully faired series-D machines). After the first few years, Vincent was joined by an innovative Australian engineer, Phillip Irving. Both men were perfectionists and workaholics; 72-hour work shifts were common in their quest for the world's best motorcycle.

After they became dissatisfied with the quality of the J.A.P.s, Vincent and Irving designed their own 500cc motor, the Comet. The story is, one day Irving stacked two blueprints and created a legend. The original HRD- Vincent V-twin of the mid-'30s was simply a pair of Comet singles arranged at 47.5 degrees on a common crankcase, mated to a Burman gearbox, installed in Phillip Vincent's spring frame. That mid-'30s monster bike could beat the best in the world on a good day. In 1938, a specially prepared 1000cc HRD-Vincent clocked an 11.75 second quarter-mile. On a bad day, clutch slippage, a balky gearbox and oil leaks might embarass the Vincent rider, rendering the bike totally incapable of slipping past 100 mph.

During World War II, the Vincent company specialized in machine tool manufacture, but as the last German rockets fell on London in 1945, Vincent and Irving labored in blacked-out offices to develop a motorcycle for the well-heeled peacetime rider. Their aim was simple; make the world's fastest motorcycle and make it last 100,000 miles.

Since steel was in short supply in 1945, the motorcycle was designed to make use of aluminum melted down from airplanes like the P-51. British government inspectors called for 80 percent of production to be exported; the Vincent's main market would be the States. (although Juan Peron's police force in Argentina was also a big customer).

For our comparison, Vincent specialist Dick Busby brought along his restored 1952 Black Shadow, accompanied by Frank Hoogendoorn on his indeterminate-age 1200cc Black Shadow hot rod. They were quite happy to run their 40-year-old machines against modern motorcycles; the only stipulation was they had to be home before dark.


FEAR AND LOATHING

The 1948 998cc V-twin unit-construction engine turned the largest and most robust gears ever fitted to any motorcycle and had a servo clutch designed to withstand 100 horsepower. The power output of the first postwar Rapides was a mere 45 horsepower, but the Black Shadow claimed 55 horsepower and the stripped Black Lightning claimed 70 horsepower. The angle between the cylinders was increased to 50 degrees and the motor was now a stressed member, the short spine frame running between the steering head and the rear shock mounts. The miniframe served double duty as an oil tank, holding three quarts of engine oil for the dry-sump twin. However, the steel frame expanded at a different rate from the aluminum engine. Vincent's answer was to bolt the front mount up tight, slot the rear engine mount and leave the bolt a little loose to allow for expansion. There were a few other doubtful engineering solutions on the world's fastest street bike; the cams were driven with a huge alloy gear that could strip and shower fragments through the bottom end, and the crank bearings could not withstand continuous maximum power (during a 24-hour-record attempt, the crank bearings failed after the first seven hours). Electrical power was generated by a puny 45-watt dynamo, a lower output device than even the 500cc Comet, meaning the after-dark performance of this road burner was limited by the glowworm headlamp. But by the standards of the day, the Vincent was mighty indeed, as was its price. The Vincent cost 50 percent more than anything else on the market, and sales were slow. In the U.S., Vincent sales were handled through the Indian dealer network. At one stage, a Vindian prototype was constructed using an Indian Chief with a Vincent engine, foot clutch and hand shifter.

In 1948, the marque earned its biggest boost when Indian dealer Rollie Free took a factory-prepared unstreamlined Black Lightning twin to Bonneville, running 148 mph on the salt. In search of the extra 2 mph, Rollie stripped off his leathers and helmet and broke 150 mph dressed in a swimsuit and tennis shoes (the shoes were size 12, several sizes too large for him. Free later claimed they slowed him by at least half a mile an hour).

The three versions of the Vincent twin - the Rapide, the Black Shadow, and the Black Lightning - were basically the same. The Black Shadows had cams picked from stock that had long timing, and the connecting rods were polished. Black Lightning engines had different cams, higher strength connecting rods, larger inlet ports, polished rocker gear, steel idler gears, racing carburetors, and a manual-advance magneto. Six types of pistons gave compression ratios between 6.8:1 and 12.5:1. The design of the combustion chamber is a classic hemi head, and the 12.5:1 compression used on the Black Lightning racers requires heavily leaded gasoline.

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ART OF THE START

Unfortunately for gentleman riders, starting the 998cc engine when it was cold was a black art. In the '50s, the height of electrical technology was still the magneto, a device from the 19th century. Magnetos don't give much of a spark at low rpm. And on a V-twin, the uneven firing periods mean the sparks must happen before or after the magneto's electrical power peak. Vincent riders often lived on hills.

The most popular motorcycle engine design of the '50s was the vertical twin, which fires both plugs at the same timing mark. This vertical twin advantage disappears if battery-and-coil or digital systems are used, but in the Vincent's day, six-volt charging systems were more unreliable than magnetos. In 1955, the Vincent motorcycle's last year, a switch to battery- and-coil ignition belatedly improved starting manners.

Indian's failure during the '50s didn't help Vincent sales, nor did Vincent's expensive forays into other fields. Vincent's water scooter was the predecessor of today's personal watercraft. But again, the technology wasn't in place; the prototypes melted their fiberglass hulls during operation and sank.

Eventually, the Vincent motorcycle also sank in a sea of red ink. Riders with money to burn were rare in the '50s. Even though purchase prices were reduced every year from 1948 to 1955, few riders could afford a Vincent. In a quarter of a century, Vincent produced around 11,000 motorcycles. Kawasaki makes more ZX-11s in a year.


KAWASAKI'S ROAD BURNER

The ZX is a superlative performer. With a top speed of 175 mph, it offers more horsepower than you can shake a stick at, all in one good- handling package.

The ZX-11's effortless speed and stealth styling mirror the Vincent's design, but technology has moved on and brute strength isn't a prerequisite to own the world's fastest. Handling and traction have moved on, too. The modern bikes's smaller but wider tires put more rubber on the road than the Vincent's 20-inch front and 19-inch rear. The Kawasaki's all-covering fairing actually shows more of the motorcycle than the full fairing of the Vincent Black Prince, introduced in late 1954; even the Prince's back wheel was faired.


TAMING THE BEASTS

One push on the ZX-11's starter button fires it. Meanwhile, the Vincent is pushed off the rear wheel stand. The long decompressor lever under the clutch is pulled in, and then the sickle-shaped kickstarter is nudged forward over compression. A big swing with plenty of follow-through does the trick, like hand-starting a model-T Ford. But the Vincent kickstart is fragile, and it will break if abused. Open the throttle no more than an eighth. The motor responds with an urgent booming. After running for a few seconds, it's warm enough to take off.

Gear selection on Dick Busby's Shadow is easy, thanks to its Ducati clutch. (Vincent die-hards won't dispute that shifting between gears is much improved with the Australian-made clutch-conversion kit, which costs around $700.) Every control on the Vincent is adjustable, even the gear lever. In seconds, the rear wheel can be reversed by hand to change gearing between its two sprockets. And spares are still easy to get, though expensive.


REVS VS. TORQUE

The Vincent has a low-rpm torque motor. It pulls smoothly from idle without complaint. The only rough spot is the click from the 150-mph speedo as it notches up the bike's speed in three- to five-mph steps (the chronometric design is mechanical, in contrast to most of today's magnetic instruments). In contrast, the Kawasaki's power hits as the needle climbs the rpm scale.

While the ZX mops up almost every bump, the Vincent's suspension shows its age clearly. The front suspension feels almost rigid and hardly yields at all at city speeds, but even then the forks must be kept in perfect adjustment. It can take three hours to adjust the aluminum-blade Girdraulics.

The rear suspension is compromised by the dual seat, which mounts on the rear fork. It's strange to have your posterior moving while the pegs and bar remain stable (if shaky). Go over a bump too fast and the affronted suspension throws your rear end right out of the saddle. The stability is helped by the 20-inch front wheel; it may be old and skinny, but the large diameter means the footprint is also large. Vincent brakes are unique; each wheel carries two 7-inch drums, with brake shoes 7/8 inch wide. The front brake operates with a balance beam between both drums. Don't believe the enthusiasts who tell you the brakes are great. They don't hold a candle to modern discs. In perfect condition they were capable of impressive 30-mph stopping distances, but old age and brake fade make them pathetic by today's standards. Fast riding requires forethought and commitment on a Vincent, while the Kawasaki is easy to ride. It's a testament to the Vincent's design that it can be used for long tours and sport rides, but it requires a degree of commitment the Kawasaki rider won't tolerate, and it means not riding after dark.


ACCELERATION VS. APPRECIATION

Both motorcycles cost a chunk of change. A Vincent can cost up to $30,000 for a pristine example. Previously escalating price trends have recently stabilized, but it still costs around 20 big ones to buy a good- running Shadow.

Expecting a 40-year-old motorcycle to compete against the best of today's road burners isn't really a fair fight. But the Vincent has proven itself capable of its design objectives; to last for years and 100,000 miles. With care, the ZX will also last, and if the motorcycle world surrenders to the 100-horsepower limit, it will hold the top speed record for another 20 years.


	                  1993 KAWASAKI           1952 VINCENT 
                          ZX-11 NINJA            BLACK SHADOW
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Suggested retail price	$8499			      $1090
  Current market price                         	      $16,000 to $30,000
           Engine type  Liquid-cooled, transverse     Air-cooled, 50-degree 
			in-line 4-stroke four	      V-twin 	       
     Valve arrangement  DOHC, 4 valves, operated by   OHV, 2 valves; 
			followers; adjusting shims    threaded adjusters 
			under buckets                   
          Displacement  1052cc                        998cc
         Bore x stroke  76.0 x 58.0mm                 84.0 x 90.0mm
     Compression ratio  11.0:1                        7.3:1
           Carburetion  4, 40mm Keihin                2, 1.125-inch Amal
                        constant-velocity             Type 29
              Ignition  Battery-powered,              Lucas Magneto
                        magnetically triggered
           Lubrication  Wet sump, 3.7 qt              Dry sump, 3.0 qt
               Battery  12V, 14AH                     6V
  Primary transmission  Straight-cut gears, 1.6637:1  Triplex chain, 1.739:1
                Clutch  Wet, multiplate               Wet, multiplate, 
                                                      self-servo
          Transmission  6-speed                       4-speed
           Final drive  No. 532 O-ring chain, 45/17   No. 530 chain, 46/21
      Front suspension  43mm Kayaba, 4.9 in. travel;  Vincent Girdraulic, 
                        adjustments for spring        3.0 in travel       
                        preload, rebound damping                     
       Rear suspension  Kawasaki Uni-Trak, one        Vincent pivoted fork,
                        Kayaba damper, 4.7 in. wheel  4.0 in. travel   
                        travel; adjustments for 
                        spring preload, rebound 
                        damping, ride height
           Front brake  2, double-action calipers,    2, single-leading-shoe
                        310mm discs                   7-in. drums
            Rear brake  Single-action caliper,        2, single-leading-shoe
                        250mm disc                    7-in. drums
           Front wheel  3.50 x 17 in.;                1.65 x 20 in.; 
                        cast aluminum                 steel rim
            Rear wheel  l5.50 x 17 in.;               1.65 x 19 in.;
                        cast aluminum                 steel rim
            Front tire  120/70VR17                    3.00 x 20 
                        Dunlop Sportmax radial        Avon Speedmaster
             Rear tire  170/60VR17                    3.50 x 19 
                        Dunlop Sportmax radial        Avon SM II
             Wheelbase  58.3 in. (1481mm)             56.5 in. (1435mm)
           Seat height  30.7 in. (780mm)              32.5 in. (826mm)
         Fuel capacity  5.5 gal (21L)                 5 gal (19L)
            Wet weight  581 lb (264kg)                500 lb (227kg)
                 Color  Black                         Black
           Instruments  Speedometer, tachometer,      Speedometer
                        fuel gauge, coolant 
                        temperature gauge, odometer,
                        dual tripmeters; lights for
                        turn signals, neutral, low
                        oil pressure, headlight 
                        failure, low fuel level
             Top speed  175 mph                       125 mph (estimate)



Pictures of the Vincent 'borrowed' from: Atlas Motor Vehicle