1981 Ducati Pantah 500SL
1981 Ducati Pantah 500SL
Claimed power: 45hp @ 9,050rpm
Top speed: 115mph
Engine: 499cc air-cooled SOHC 90-degree V-twin, 74mm x 58mm bore and stroke, 9.5:1 compression ratio
Weight (wet): 433lb (197kg)
Fuel capacity/MPG: 5gal (19ltr)/40-50mpg
Price then/now: $4,549/$2,000-$5,000
You only get one first love, and no one’s counting after that. But if you remember your first, you’ll never know which one’s your last. Best to keep a restless heart, and be fickle with devotions, especially with old bikes.
“Darmah” Dave Eulberg’s love affair with 1970s-era Ducatis happened the way it often does. From a bored 15-year-old dirt-biking on a Montana farm, bikes became a flourishing addiction in progress. From Honda CB350 rebuilds in his parents’ basement, Dave became a Honda dealer technician whose eyes were drawn to the Superhawks and Hawk GTs he’d work on. Forsaking reliability and embracing a problem-solving nature, he purchased his first English bike, a 1977 Triumph Bonneville. And if you can love old English iron, you’ve got an inside track to an unhealthy obsession with vintage Italian twins. Enter the less glamorous Ducatis of the 1970s.
Though Dave’s first Ducati was a 1978 SD900 Darmah, his hunt for a second Ducati began as an interest in vintage racing took hold. After a track day on the Darmah, Dave realized he’d better start looking for a Ducati that was more suited to racing. Unable and unwilling to shell out ransom-like amounts for a 750GT or 900SS, Dave settled on the lesser-known Pantah. But trying to secure a Pantah means lots of searching and little finding.
Beyond scanning Craigslist or eBay, leads came from a well-cultivated network of fellow riders and old acquaintances. After a few months of pounding the pavement, Dave’s search finally paid off. He found his Pantah in Tennessee in the fall of 2013. He brought it home to Illinois on a December day during the worst Midwestern winter in a generation. He was pleased to find it nearly mint aesthetically, but in need of work to make it roadworthy. Having been part of a collection, the Pantah had sat for a number of years. “Cryogenically stored” in Dave’s garden shed, it would sit for another month and a half before a light recommissioning could begin. Though he didn’t anticipate finding an almost 100 percent period-correct example, it was the only one for sale at the time. Understanding the value of the bike he’d found, Dave decided to stay on the lookout for a less pristine example to race.
From the beginning
How Dave’s Pantah came to be is almost as interesting as how the bike itself came into existence. The Pantah is best understood as a collection of firsts for Ducati. Almost everything about the Pantah had shown up on previous Ducatis, just not together in one package. Ducati’s innovations and ingenious designs in the 1970s were paired with poor sales figures and even worse marketing decisions. The Pantah was born from improbable triumph and colossal failure.
The triumph was Mike Hailwood’s amazing 1978 TT win. It’s hard to over dramatize the impact of his win, both in terms of racing trends and prevailing wisdom. Hailwood’s win on a bevel-drive 900 Super Sport helped dispel the notion that a V-twin was obsolete in an age of inline fours; Ducati ultimately sold over 7,000 Mike Hailwood replicas. But if Hailwood’s historic TT win made a case for the continued relevance of V-twins, it did nothing to solve the problem of prohibitive production costs for the venerable bevel heads.
Time to modernize
Ducati had already spent the better part of the 1970s on that most un-Italian of endeavors — economizing. Ducati was trying to modernize their line and reduce production costs. While the square-case 860 and parallel twins produced between 1975 and 1983 were a success in terms of production costs, their terrible market performance rendered this victory moot. The square-case 860s were a sales flop, largely due to their styling, while the parallel twins were an abject failure in almost every measurable metric. The parallel twins were underpowered and had a propensity to snap cranks. The styling cues taken from the 860s were the final nail in the coffin for the 500 GTL parallel twin, never mind Ducati engineer Fabio Taglioni’s refusal to take part in its initial design.
Even before Hailwood’s TT triumph, Taglioni had already been tasked with developing a new model. 1976 saw Taglioni given some measure of redemption in being asked to bring his belt-drive V-twin concept from 1971 back to life. The 500SL Pantah he’d develop would mark a departure from Ducati’s established build practices and design concept. Its continued nod to cost considerations made perfect sense for a company looking to salvage its fortunes while leveraging the legend-making success of Hailwood’s TT triumph. More than just reflecting Ducati’s racetrack success, the new Pantah aimed for success with the bean counters and the sales floor.
The Pantah was based, in part, on two existing Ducati race bikes, the 1973 Armaroli 4-valve belt-driven twin and the 500cc bevel-drive Grand Prix racer of 1970. By smartly borrowing from both examples, Taglioni’s last design for Ducati was a culmination of his life’s work, uniting virtually all his innovations into one bike that would form the basis of almost every Ducati for the next 30 years.
The belt-driven cams, trellis frame and desmodromic valve actuation provided the soul of what we know as the modern-day Ducati. While the desmodromic valve system solved valve float problems in a mechanically complex manner, the belt-driven cams solved a different problem — an economic one, as the belt-drive system was far cheaper to produce and assemble than the bevel-drive.
Completing the initial model in less than six months, Taglioni built a 74mm x 58mm engine with 9.5:1 compression ratio. It followed the existing 90-degree twin cylinder layout with vertically split cases, but with desmodromic heads housing 60-degree angled valves as on the heads Taglioni designed for the parallel twins.
The swingarm pivoted on bearings in the gearbox casing, with the clutch primary now on the left side of the engine to facilitate the left gearshift placement. Absent was a kickstarter, with the starter motor neatly tucked under the now right-offset front cylinder. The belts and valve gear were on the right side, driven by a jackshaft spun by the crank on the left side, resulting in a narrow, 14.8-inch wide engine. A wet clutch connected to a 5-speed gearbox, and the trellis frame designed by Taglioni held the engine at six points.
The engine had a one-piece crankshaft with two-piece connecting rods running plain-bearing big ends. While the “Gilnisil” bore plating (a trade name of Nikasil) ruled out any reboring, the 500 platform easily translated into the subsequent 600 and 650 Pantah iterations. Initial prototypes used 32mm Dell’Orto carburetors, but production bikes including the 600SL that came a year later wore larger 36mm Dell’Ortos. Power output on the first 500SLs was quoted at 45 horsepower at 9,050rpm.
The start of 1978 saw a finished prototype, but Ducati’s chaotic finances and management kept the Pantah from production until September 1979. Released simultaneously with the 900 Mike Hailwood Replica, only a small number were produced, in order to gauge customer demand. The first 163 were delivered in red and silver, with a telltale “.1” designation after the “DM 500L” serial number prefix.
The bike’s reception was mixed. A May 1981 Cycle magazine test found the bike ran rich, with difficult starts on cold mornings. The airbox and overly rich jetting were singled out as the culprits, keeping the bike from performing well. Paired with a comically tall first gear, the Pantah seemed to regard the quarter mile as a juvenile standard of performance not worth its time. Cycle was able to coax a 13.66-second/98.14mph run out of their example, barely a half-second faster than a Suzuki GS450. The gearbox, however, was praised as superior to anything produced in Japan, smooth and with no missed shifts or false neutrals.
The Pantah today
They say it’s only original once, and in terms of perfect as possible paint and finish, surviving Pantah 500s are few. Dave’s example proves the adage that you should always buy as much bike as you can afford. A light amount of sun fade brings out almost archaeological details, like the fact that too-large washers helped secure the fairing at some point. Yet a few tiny tears in the seat fail to detract from the original vinyl covering and foam, still supple and wearing the Ducati logo on the bum-stop seat.
Taking the Pantah out for a ride on a crisp, September day, the bike’s charm takes a few thousand revs on the tach to become apparent. Like a bored teenager the Pantah needs stimulation, but it flashes brilliance at the most opportune moments. Dave’s bike is beautifully sorted, but little happens before 5,000rpm shows on the tach. Get to there, however, and it’s all fun until the readily reached redline.
A tall first gear snicks easily into second, where the bike’s coltish legs start to stretch. Soon, only the light wobble and vibration from the fiberglass fairing interferes with the restrained twin. In contrast to Dave’s Dharmah, the Pantah is quiet, modest and poised. The Conti pipes don’t bark as much as they repeat your marching orders, and even redlining just brings about a loud hum, making for a civilized impression.
The understated strength of the Pantah becomes apparent on winter-scarred Illinois roads. The Pantah seemingly can’t take a bad line, and there’s no crumbly pavement that can ruffle the fur of this cat. Being used to a wide inline four pushing the front tire into turns, the slim twin and trellis frame is a revelation. Several times I get too hot into a turn before I remember; duh, just lean over a bit more. It’s as simple as that. The riding position is oddly comfortable to my 5-foot 10-inch Nordic build and limbs, and the rearsets offer a pleasing rider geometry, with some hand fatigue setting in after an hour or so. The rear fairing with its bum-stop looks fantastic, and despite the seat being about two inches thick and original, it’s quite comfortable. The unfinished interior fiberglass environs of the front fairing are strangely pleasing, though vibration is a reminder of the bike’s inherent minimalism. I ask Dave about the Napoleon mirrors he mounted, thinking it odd he’d choose modern mirrors since he’s such a stickler for originality. “Oh, they didn’t come with mirrors.” he replies. Minimalism, indeed.
I’ll take two
When a second Pantah came up for sale in Colorado, Dave finally had a track bike to go with his pristine, blue, original Pantah. Dave took a novel approach to transporting his new purchase back to Illinois. Deciding the extra gas money and slower speed of a trailer was unnecessary, Dave removed the interior of his Ford Focus hatchback and disassembled the bike in the previous owner’s garage before stuffing it into his Ford for the trip back to Chicago. Mind you, he did it over the weekend, covering 1,800 miles in a little over 37 hours.
So what was the draw of the second Pantah that he went to all that trouble? “It has the period correct Verlicci handgrips and the original airbox,” he explains. These final details were the last things needed for the first Pantah, making it original at last. Details like that separate mere survivors from something that could more accurately be called a time machine. Yet the point isn’t about going back in time, it’s about dragging the past into the present. Riding a machine virtually unchanged from when it left the factory, it’s possible to not just glimpse the past, but grab hold of it and make it live and breathe in the present. You can almost feel the same wind, hear the same engine whine and feel the same buzz under the pegs that someone else did in 1981. It’s a priceless feeling — until you add up the receipts.
As for the “spare” Pantah, Dave painted it blood red and re-christened it as a track bike and AHRMA racer. Dave took sixth place with it at his first ever race, at AHRMA’s Road America contest last June. Throw in a few track days and the red Pantah got to stretch its legs and get a right proper Italian Tuneup.
With the Pantah’s strong race heritage, Dave’s got the right idea. The 500SL and the1981 600SL and 1983 650SL that followed it all had success on the track. The 500 was a capable production racer, notching the 1980 Spanish TT2 Endurance championship, plus the German and Canadian championships for 500cc production motorcycles. The bloodline that began with the 500 reached its zenith with the TT2 racer of 1981 and the legendary TT1 750 of 1984. What they gave up in displacement they more than made up for with spectacular powerbands mated to light and nimble-handling frames. If the Pantah was born from an exercise in economic modernization, it still provided a compelling platform for racetrack performance.
And the Pantah shown in this lovely pictorial? As I write, Dave’s put out the word that he’s thinking about his next project, and the lure of a round-case 750 GT is strong. He’s not selling the Pantah at the moment, but future seeds are being sown. A restless nature demands new challenges and new projects. And beyond the search for new mechanical and historical projects, maybe a small part of it is looking for the next bike that makes the heart flutter a bit. After all, you never know which love will be your last. Motorcycle-wise, anyway. MC
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