Ktm Duke

KTM DUKE

SUPERMOTARD STYLING STRIKES AGAIN

THE BARK OF THE EXHAUST TELLS YOU IT'S A Thumper, but the authority of that sound makes clear this is no ordinary Thump. KTM has just unleashed the most potent Single to hit Europe's cobblestones, and it's got a name that suggests its nobility. It's called the Duke 620. Supermotard-weird in style, with sportbike suspension, fat 17-inch rubber and a 609cc engine packed with grunt, this thing will flat frazzle your brain cells.

The Duke is KTM's first pure road machine. In designing the bike, the Austrian company drew heavily on its championship-winning enduro and motocross experience, but shunned the easy path of compromise. The Duke is an unashamed street fighter, completely without dirt pretensions.

Rated at 56 crankshaft horsepower, the engine is by far the most powerful Single on the market and is an off shoot of KTM's experience on the racetrack, which includes winning the German Supermono cham pionship in 1992 and'93. It

is based on KIM's LC4 enduro engine, but the crankshaft, piston and cylinder head are all-new. It also has a crank-driv en balance shaft, a 40mm Dell'Orto carb and tuning parame ters that provide throttle response stout enough to rocket the bike forward, its front wheel pawing the air, with a flick of the wrist.

This bike is not for sissies. First of all, there’s no electric start. Instead, the machine needs to be kicked over with the left foot, and don’t forget to use the compression release. Once you have the knack, the engine bursts easily into life. The liquid-cooled engine, with massive dual radiators and a twin-port head, crackles away at idle and revs instantly when you open the throttle.

The 609cc motor has real bottom-end power, pulling strongly and smoothly from 2500 rpm. But things start to get really serious when the tach needle hits 4000 rpm. You keep the throttle cranked open and wait for the inevitable tapering-off of power-but it never happens. This engine just keeps churning until it hits its 8500-rpm redline, by which point you’re doing an indicated 112 miles per hour. Not to be sniffed at, especially since the powerband is so wide you rarely need to swap gears. When you do shift, you find feather-light clutch action and a very smooth-shifting closeratio, five-speed gearbox-identical to the one KTM uses in its Sound of Singles roadracer. At play on the open road, I had no complaint, but in town there’s too much of a gap between first and second. You’re either slipping the clutch in second or you’re over-revving in first gear. A different ratio spread in the lower gears would ease city life.

Most Singles feel gentle, but the Duke isn’t most Singles. It’s powered by an engine that demands respect, and overly zealous application of the throttle can get it seriously out of shape, bringing the front-end up or the back-end out. This isn’t helped by a notchiness in the throttle. That problem exists because the carb sucks in air at such a rate that its slide sometimes will lightly stick in position. As you pull against that stickage and break the slide free, it’s very possible to get a lot more throttle than you bargained for. KTM says there isn’t much it can do about that. I ended up slipping the clutch to feed in the power smoothly coming out of comers and found it cured the problem. For certain, that’s what you’ll have to do in the wet.

A parenthetical word, here. For those who would avoid the 609cc engine’s heavy hit, KTM is building a 398cc version of the Duke. The 400 motor chums out a claimed 42 horsepower and is far kinder to the rider, without the massive power pulses to break the rear tire loose. A smaller, 38mm carb means the throttle action is much better.

So, the Duke 620 has harsh sides, but its beauty is that it’s a hell of a lot of fun to ride. Head down over the instruments, arms splayed out and elbows up motocross-style, the Duke’s riding position is aggressive and inspires the kind of confidence that makes you want to do naughty things.

Chances are, you’ll get away with them. The bike feels skinny, weightless and dirtbike-tall, and its compliant, racequality WP suspension makes the handling quite stable. A wide, flat handlebar give tremendous leverage and instant steering response, while the ample trail offers good stability, even at high speed. The Duke’s 17-inch wheels wear fat, sticky Pirelli rubber that also helps you escape the consequences of overexuberance.

As the 27.5-degree steering-head angle suggests, steering is not super-quick, although the Duke’s claimed 315pound dry weight makes most streetbikes feel cumbersome by comparison and means that the Duke will be more than a match for them down twisty roads. It loses out because of its height, though-it just cannot be flicked from side to side instantly.

Excellent damping from the 40mm upside-down fork and rear shock, which works on a rising-rate linkage, keeps the tires glued to the road. Both fork and shock are adjustable for compression and rebound damping. Front preload can only be adjusted by dismantling the fork, which does need work-the spring rate was firm enough to stop dive under braking, but made the front choppy over some surfaces.

Braking is awesome. KTM designed and manufactured the semi-floating 12.6-inch single front disc, which is gripped by a four-piston Brembo caliper fed by braidedsteel lines. Lever action is light, sensitive and progressive.

The rear setup, however, is a bit too powerful. Under hard braking, just a touch of the pedal can lock up the 8.7-inch disc. Here again, the bike’s forgiving chassis will get you out of trouble.

Big Singles are horribly prone to vibration, but KTM has done its best to eliminate the Duke’s vibes by installing a gear-driven balancer. The weighted, tapered handlebars are also claimed to reduce vibration. The result is a surprisingly smooth motor, especially when it is turning more than 5000 rpm. Mirrors, footrests and the seat suffer a little, but those are the last things you’ll be thinking of as you wring the max out of the machine.

The Duke generally is reasonably comfortable, although it will never make a tourer. The seat is well padded and you never feel cramped, though the 34-inch seat height might put off shorter riders. The small handlebar fairing, which incorporates adjustable twin headlamps, gives a little upperbody wind protection. The rider’s legs get a bit of protection from the radiator air scoops on either side of the 3-gallon plastic fuel tank.

To KTM’s credit, the Duke glistens with quality. Everything from the tail unit to the front fender and easy-toread instruments has been thoughtfully designed. Even the stainless-steel exhaust system is a thing of beauty.

But as good as the Duke is, it does have a few faults. For starters, it rocks dangerously forward on its too-close-tovertical centerstand, and there was no sidestand on the bike used for this test. KTM says the first problem will be sorted for production, while a sidestand will be optional. Also, warning lights are impossible to see in daylight, and there is no kill switch or water-temperature gauge.

But these small glitches shouldn’t keep KTM from selling all the Dukes it can make. Just 450 620s and 50 400s will be built this year. About 300 are going to Austria and Germany, and two-thirds of those already have been sold. That’s particularly interesting, in light of the bike’s price-the equivalent of about $8250, including taxes. This makes the Duke an expensive choice. But excellence equals value, especially when none of the Duke’s European competitors-BMW’s new and highly touted F650 Funduro, MuZ’s Skorpion or Aprilia’s very pretty Pegaso—can rival it for speed and power. For now, at least, the Duke is king of the road-going Singles. -Oily Duke