2014 KTM DUKE 390 - First Ride

This fun street-legal single arrives in the US this fall. Do Americans want such a machine? We do.

2014 KTM 390 Duke on-track action shot

KTM snagged three Cycle World Ten Best trophies this year, thanks to an impressive trio of machines all powered by four-stroke engines: the 500 EXC, the 1290 Super Duke R, and the 1190 Adventure. This is a sign of just how far the Austrian make has come since the days when KTM was known mostly for two-stroke singles, enduro machines, and Pentons in the US. Today, KTM is especially competent in the world of high-performance four-strokes, as proven by its absolute dominance in the 2013 Moto3 series and its ability to fend off the Honda counter-offensive this year.

In recent years, KTM has developed a whole new generation of road models powered by high-performance four-stroke singles that have injected life into a category that has produced legendary machines such as the Ducati Mk 3 250-350 (in both spring and Desmo versions) and the Harley-Davidson Sprint 250-350. Those singles of yore were light and very agile, and they revved like crazy as they produced nearly 100 horsepower per liter, a big success for then. Then, however, roadworthy midsize singles went out of fashion, replaced by larger enduro mills that had far less specific output and typically ran out of breath around 6,000 rpm, right when you expected them to come on strong.

2014 KTM 390 Duke static side view

When motocross made its historic shift away from two-strokes, it marked the return of four-strokes with very high specific output. KTM poured the wealth of its experience in four-stroke motocross and ISDT competition into its whole line of its street-legal singles, starting with its Duke models. That stated, the Duke 125, with 15 horsepower, is an anomaly; that's the maximum power allowed for a 125cc to be legal on the streets of Europe. A look at the Duke 200 numbers proves KTM's great competence in four-stroke thermodynamics. The Duke 200 produces a claimed 25 horsepower at 10,000 rpm, about what a Ducati 250 Desmo did at 9,000 rpm.

The king of the KTM lightweights, the subject of this First Ride, is the Duke 390, a roadster that produces a claimed 44 horsepower at 9,500 rpm. I took this fully civilized street-legal KTM to Pirelli R&D’s test track to see how I interfaced with a lightweight single and if it triggered any nostalgia for my Ducati Diana 250 that I sold to a friend in Columbia, South Carolina, when I returned home to Italy after going to college in the US. I was also curious as to how the KTM 390 Duke would deal with my 200-plus pounds.

With the Duke 125/200/390 family, KTM has made everything very much “real motorcycle like” while also exploiting the cost-cutting opportunities provided by the new factory in India. The cast aluminum swingarm is a perfect example of the excellent aluminum casting technologies achieved in India. It’s simple, light, and sturdy, yet easy to cast in one pass, with no additional major machining requested. Most important, the 390 engine was so smartly designed that it can be shoehorned into the chassis originally conceived for the 125 an 200cc units. Aiding this effort is a gearbox with vertically stacked shafts, which keeps the overall length unchanged from the Duke 125 and Duke 200 measurements.

390 DOHC 4-valve single.

The 390 engine displaces 373cc from a solidly oversquare 80.0mm bore and a 60.0mm stroke. With a pair of chain-driven overhead cams, the four-valve single breathes through a 46mm throttle body, and the Bosch fuel injection is fully integrated with the ignition. The exhaust, with catalytic converter, is well muffled. With a 12.5:1 compression ratio, the KTM powerplant supplements its claimed 43 horsepower with 25.8 pound-feet of torque, which peaks at 7,250 rpm. There’s a very ample spread of 2,250 rpm between peak torque and peak power, which translates to a very flexible powerband.

This little engine brings back all the magic of the great singles of the past, plus more. It’s compact, light, fully civilized and free of vibration, thanks its balance shaft. Like all other Duke singles, the 390 is a state-of-the-art design based on a forged crankshaft with a cap-type connecting rod, all turning on plain bearings. This very modern engine mounts in a steel trellis frame based on two main oval-tube “spars” integrated by tightly woven small-diameter triangulations. The frame braces the engine at a number of attachment bosses, for a fully integrated construction that brings high torsional rigidity to a structure that is lean and light.

Chassis specifics include a 53.8 in. wheelbase, plus a steering axis geometry with 25 degrees of caster and 3.9 in. of trail. The wheels are cast aluminum units, shod with Metzeler Sportec radials, size 110/70-17 in front and 150/60-17 in back. The brakes, with a single rotor at both ends (300mm front, 240mm rear) feature a four-piston radial caliper in front and a floating single-piston rear. Two-channel ABS from Bosch is standard, and WP, which is owned by KTM, provides the inverted 43mm fork and the semi-cantilevered rear shock. Claimed dry weight for the KTM Duke 390 is 306.4 pounds dry, and its sporty double seat is 31.5 in. above the ground. Lastly, a tapered aluminum handlebar puts the grips within easy reach, aided in part by the short and well-shaped 2.9-gallon tank.

2014 KTM 390 Duke front wheel details

The Duke 390 engine starts promptly and settles into a steady 1,000-rpm idle. The riding posture is comfortable for a daylong ride, and the engine responds vigorously to the throttle inputs. Unfortunately, the grip action needs to be improved because I have to reset my hand on the grip whenever I wanted the fully open position.

Nevertheless, the 2014 Duke 390 is a highly spirited ride, and the KTM single is a true force of nature. It pulls hard from 3,000 rpm, and keeps revving all the way to the limiter at well past 10,000. And it stays civilized the whole time. The torque delivery is more vigorous than I expected, granting me all the pulling power I needed to balance my weight and the machine’s when leaning at knee-grinding angles in a medium speed bend. At first, I took this turn n third gear, but soon found that fourth was a much better choice because it helped me a solid 100 mph going down the following straight. Very impressive!

Soon, the Duke 390’s cornering clearance started running short, especially on the right side where the footpeg seemed to grind sooner than the left. Which explains why the sportier and fully faired RC 390 sports an 820mm (32.3 in.) seat height and steeper (23.5 degrees) steering geometry, courtesy of a taller rear shock absorber. I wished the RC 390 were available that day, because the Duke 390 really proved superbly balanced on those Metzeler Sportecs.

2014 KTM 390 Duke action shot

While it’s not a surprise that the KTM Duke 390 is so agile, light and nimble, I was most impressed by how stable, precise, and surefooted it is. The suspension is a little harsh, but on relaxed rides around town and in the country the bike didn’t cause any discomfort, thanks largely to the well-shaped and nicely padded seat. On the down side, the Bybre brakes, made in India by Brembo, proved inadequate for track use. They’re spongy and didn’t communicate well, which makes the ABS a must. That, however, is the only flaw in this spirited little KTM, which is fun at the track as it is on the road, where you can keep up with the big guys using very little gasoline. This, friends, is the new king of city traffic, way above any scooter I’ve ridden.

KTM North America says the KTM Duke 390 is expected to arrive in the US this fall, almost certainly as a 2015 model. Are Americans interested in a sporty, lightweight streetbike like this KTM? Price and release date have not been announced.

SPECIFICATIONS

2014 KTM 390 DUKE
ENGINE Liquid-cooled single, four-stroke
DISPLACEMENT 373.2cc
BORE & STROKE 89mm x 60.0mm
CLAIMED HORSEPOWER 43 hp at 9500 rpm
CLAIMED TORQUE 25.8 lb.-ft. @ 7250 rpm
TRANSMISSION Six-speed
CLUTCH Wet multiplate
IGNITION SYSTEM Electronic, with digital timing adjustment
FRAME Tubular-steel space frame, powdercoated
FORK Inverted WP fork
SHOCK ABSORBER WP Monoshock
FRONT SUSPENSION 5.9 in.
REAR SUSPENSION 5.9 in.
FRONT BRAKES 300mm disc brake with four-pot brake caliper
REAR BRAKES 230mm disc brake with one-pot brake caliper
STEERING HEAD ANGLE 65°
WHEELBASE 53.8 in.
GROUND CLEARANCE (UNLOADED) 6.7 in.
SEAT HEIGHT (UNLOADED) 32.5 in.
FUEL TANK CAPACITY APPROX. 2.9 gal.
CLAIMED DRY WEIGHT 306.4 lb.

Action shot #1

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Action shot #3

Action shot #4

Action shot #5

Action shot #6

Action shot #7

Static left-side view.

Static front 3/4 right-side view.

Static right-side view.

Static front 3/4 left-side view.

Static rear left-side view.

Static rear 3/4 right-side view.

Rear view.

Telefork disc brake.

Front disc brake ABS hall effect wheel and sensor.

Headlight.

Instrument panel.

Fuel tank (left-side view).

Fuel tank (right-side view).

Details of engine and radiator.

Lower spoiler with oil radiator tank.

390 DOHC 4-valve single.

Engine (left-side view).

Cantilevered rear shock absorber.

Rear Bybre disc brake with ABS hall effect wheel and sensor cast aluminum swingarm.

Cast aluminum rear swingarm.

Rear disc brake with ABS sensor and hall effect wheel.

Rear wheel chain adjuster and nips for race-type jack.

Underbelly exhaust system and silencer.

Double seat.

Crank assembly.