There’s something not quite serious about single-cylinder engines in road bikes. As one part of a manufacturer’s broader portfolio they do satisfy that small niche of riders prepared to put up with mediocre power, vibration, low-rev lumpiness and lethargic throttle response in exchange for‚ well, something I’ve never quite worked out if it’s supposed to be more than budget utility transport. But no bike company truly comes of age until it can offer a bike with an engine of two cylinders or more.
As one of the world’s leading dirt-bike specialists, the 50-year-old Austrian KTM factory has been excused its reliance on singles because these demonstrably work best off-road. But the company is ambitious, aiming to become Europe’s largest motorcycle factory and intending to achieve this goal by expanding into road-bike manufacture. It’s a perfectly realistic target, too, with current production closing in on 80,000 machines annually, and even excluding KTM’s 16,000 children’s minibikes (albeit authentic off-road ones), that’s still almost double Triumph’s annual output, more than Ducati or Aprilia (discounting Aprilia’s scooters), and a not-too-distant second to BMW’s 90,000.
Yet as far as road bikes are concerned, KTM has barely started. The first, and until now only, one in the company’s modern era was the Duke 620, introduced in 1996 as a 609cc single with stylized supermoto looks, essentially still a dirt bike with road wheels and as such, just a toe-dipping exercise in the expansive road-bike pool.
With the new KTM 990 Super Duke, the company has not only plunged in headlong, it’s set to make quite a splash. At the heart of the 990 is a 999cc, 75-degree V-twin engine with double overhead cams, designed by KTM and based on the 60cc-smaller unit of the 950 Adventure enduro bike, the factory’s first twin. Lubrication is by dry sump, in order to reduce the engine’s height, and the bore and stroke dimensions are well oversquare at 101 x 62.4mm. Both have been increased from the 950s in order to preserve the bore-to-stroke ratio, despite the extra cost of doing this. The fueling comes through a 48mm-throttle-body, Keihin dual-butterfly injection system, pioneered on the Suzuki GSX-R750 but appearing on more and more bikes as the best way to overcome the characteristic sudden power delivery of many other injection systems.
It’s a very compact design-the timing-chain shaft, for example, also drives or is driven by the electric start, water pump, and crankcase ventilation system and acts as a counterbalancer to reduce vibes. Overall weight is just 128 pounds, substantially lighter than any Japanese or Italian liter V-twin.
Power is a useful 118 bhp, but far more important is how much is available across a broad spread of its rev band. The torque peak of 74 lb-ft arrives at 7,000 rpm, but with anything from 3,500 rpm to 9,500 rpm showing on the orange-faced tacho (KTM’s unsubtle corporate color shouts at you from all sorts of unexpected places) the bike leaps forward at the throttle’s bidding with an eagerness and crisp immediacy that’s compelling fun.
At a claimed 406 pounds dry it’s light, so while acceleration is not superbike hard it’s not so far off, and it’s accompanied by a gnarly vibration that brings the bike to life without interfering with comfort. KTM’s engineers emphasized an even power delivery in preference to concentrating on outright horsepower, which rightly, they say, is no use anyway on an unfaired bike like this, and it really shows, as the Superduke pulls strongly and evenly, free of dips in the torque, glitches or stutters.
The exhaust note is astonishing, partly for how the volume came to pass European emissions regs (even stricter than U.S. ones, sadly), but also for its delicious purring-lion quality that for me has it going straight in to the number-one spot in the ’05 bike sound charts, ousting Ducati and Kawasaki from the top positions.
The six-speed transmission is pure dirt bike, and how many other manufacturers could learn from that. Forget the heavy-ish clutch the moment you’re rolling and just tap the lever to grab the next ratio, up or down the box, the Super Duke doesn’t care, while its obedience is instant and total. The company’s offroad roots are hinted at in the riding position, too, which offers a fairly high and wide straight bar that encourages a dirt-bike rider’s elbows-out stance. It takes a little getting used to in corners but after an hour you’ll have forgotten about it.
Some of that’s because the turns are such consuming fun-it’s hard to believe at times the Super Duke is a one-liter machine as it displays all the agility of a sports 600, flipping down eagerly into turns and holding tight, fast lines once it’s there. The tubular steel, Ducati-style trestle frame, which weighs less than 20 pounds and is based on the 950 Adventure’s, has a fairly steep rake angle of 23.5 degrees. But neither the 4.1-inch trail nor 56.6-inch wheelbase are especially radical, so this must come down to a low center of gravity and light weight. At times the front feels a little too light and over-responsive, especially on bumpy surfaces, where the bars can shimmy and flap disconcertingly. Some feedback is lost for this reason, too, so it doesn’t inspire as much confidence in the front end as a Ducati Monster S4R, for example, and at very high speeds the Super Duke can be nudged into a weave or wobble at the tiniest provocation. Grip the bars tightly to stop from sliding back on the seat because of the windblast, as you have to, and the buffeting alone is enough to set up a wobble. Relaxing your grip cures it but then you start to slide back.
But lose this and you’d lose the essence of the bike anyway, along with, more pragmatically, its outstanding agility. As for very high speeds, the exposed riding position renders them academic, if legal enforcement hasn’t already done so.
The sharp and willing theme continues with the brakes, high-spec Brembos with four pistons and four pads apiece that suck the front end onto the road and spin the digital speedo down even faster than it climbs, while the equally high-spec WP suspension-48mm fully adjustable male-slider fork and a rear shock connected directly to the beautifully constructed aluminum swingarm-does a fine job of keeping rubber pressed against tarmac. Unusually, you get the facility to adjust the damping for high and low suspension speeds independently as well as the usual compression, rebound and spring settings to play with, although as stock the bike suited me just fine.
The aggressively angular styling looks uninviting to sit on but there’s no doubting its head-turning powers-this really is a dramatic-looking machine, and it does work ergonomically. Comfort and KTM have been strangers until the Super Duke, which has an all-day saddle and spacious riding position, but it’s a shame the fuel tank is so small at four gallons, effectively relegating the bike to weekend toy status-you’ll generally be looking to refill in less than 100 miles. Those scalding hot silencers-heated even more by the three-way catalytic converter nestling deep inside-are exactly where pillions will reach for when caught out by an unexpected punch of acceleration, so issue them with oven mitts before a ride.
The mirrors are much more effective than you’d expect, and some real quality details abound. The handlebar, for example, is a gorgeous tapered aluminum Renthal, and both brake and clutch levers operate radial master cylinders via neat, easy-to-use span adjusters.
The 990 Super Duke is not as powerful as an Aprilia Tuono nor as secure-handling as a top-spec Monster, but overall it’s no less a bike for these or any other reasons, bringing a distinct and welcome character to an already rich and exciting category. Now let’s hope that KTM elects to bring it to the United States someday as well.
