KTM 790 Duke Prototype Road Test: Filling the gap

First ride on a pre-production prototype of the 2018 KTM 790 Duke due to be launched at the EICMA Milan Show on November 7

KTM is Europe’s largest motorcycle manufacturer, with 203,423 bikes sold under its KTM and Husqvarna brand labels in 2016. But until now, the only multi-cylinder motorcycles the Austrian company has made have all been 75º V-twins based on the LC8 engine designed in-house powering the 950R works racer with which Fabrizio Meoni won the 2002 Paris-Dakar Rally. This duly reached production the following year in the 950 Adventure, and various derivatives of it up to and including the mega-motor powering the current 1290 Super Duke, have all been based on that same V-twin platform. As such, over the past 15 years the 75º V-twin format has essentially fuelled KTM’s growth to be Europe’s No.1 onroad, to go alongside its undisputed world crown as the king of the offroad sector, gained by its Read to Race single-cylinder products.

But that’s all going to change next month with the marketplace debut of the 790 Duke at the EICMA Milan Show on November 7, a 2018 model powered by an-all new 800cc parallel-twin motor designated the LC8c – as in ‘compact’. KTM engineers led by Philipp Habsburg, the company’s Vice President of R&D, have been working on this for the past three years, and while it will initially power two distinct variants, the Duke streetrod and the multi-purpose 790 Adventure, expect a range of different models using the same engine which will in time together represent KTM’s best-selling onroad segment. That’s the expectation of KTM AG board member Gerald Kiska, whose Salzburg-based Kiska Design company has been responsible for designing every single KTM model since 1992, when KTM’s current president Stefan Pierer took over the company. That includes the unpainted black 790 Duke prototype I found awaiting me at the KTM Technologies building across the road from Kiska Design, when I was summoned to Salzburg for an exclusive first look at this significant new model in KTM’s history - including a brief getting-to-know-you debut ride on this well-used development bike

“We think we have a good offering in the entry level and lower capacity onroad sectors with our smaller singles made in India by our Bajaj partners,” says Kiska. “And for sure we have a super competitive product at the top end with the different Adventure models and the 1290 Super Duke, including the GT. We get our customers started on riding bikes with the 125 and 200 Dukes, then we take them to the next stage with the 390 or 690 singles – but after that we lose them to another manufacturer, because we don’t have a middleweight model to offer them. OK, maybe we get them back again later on – but not necessarily, so that’s about to change with this bike you’re riding, which we think is the answer to that hole in our range.”

“However, it’s even more important to have an offering in this sector than simply filling a gap in the cradle to grave progression through the KTM range,” Kiska continues. “The middleweight sector for bikes from 750-900cc has become super-competitive, with 11 different manufacturers contesting a segment that has become a very significant one in terms of sales numbers. It’s a kind of crossroads of customers, which caters to former newbies on their way up the capacity scale, as well as returnees who don’t want to jump straight away onto a litre-plus bike, and Super Duke owners who are maybe getting older and want a quieter life! Then there are women, too – they’re becoming an ever more important segment of KTM customers, and we have to offer them something that’s got more performance than our singles. So all of this together made a case for this new family of bikes kicking off next March, when production will begin of the 790 Duke.”

OK – but why a parallel-twin? Why not build on KTM’s 15-year experience of V-twin engineering and produce a scaled-down little sister of the current family of motors? “We looked at doing that, of course,” says KTM R&D’s LC8c project leader Jürgen Hager, “but always in comparison with the other way of doing it, with a parallel-twin design. We were aware that our existing KTM customers would be coming to the bike from a single-cylinder model, so we wanted to make it look not so different to what they were already riding. Then to go with our Ready to Race philosophy we wanted to establish a visual link with our Motocross bikes, so all of this together meant that the parallel-twin concept won out. The fact that it also centralises the mass of the engine, which allowed us to design a more compact, easier-handling motorcycle, was also a key factor.” 

Those were important dynamic reasons, according to LC8c Product Marketing manager Adriaan Sinke, who’s been responsible for tying together the different strands in development of the 790 platform between engineering, styling, production and the marketing department “We wanted to make a bike that’s intuitive to ride, that’s light and responsive with the extra performance of a twin, but without sacrificing the agility of a single,” he says. “That definitely told in favour of a parallel-twin - so that’s what we chose to take forward.” 

The result is a compact, lightweight, liquid-cooled dohc eight-valve engine with a 270º crank to deliver good traction, fitted with twin counterbalancers to eliminate vibration – one in the cylinder head, the other driven off the crankshaft. There’s chain drive to the camshafts offset to the right of the cylinders, while the six-speed gearbox allows clutchless quickshifting both up and down the ratios, and is matched to a PAS/Power Assisted Slipper oil-bath clutch which is cable-operated for ease of maintenance, and to save weight. KTM won’t quote a weight for the bike yet on the grounds that the prototype I rode is still work in progress, and is likely to evolve further before it enters production five months from now – but for sure given KTM’s past focus on saving kilos, it has the potential to be a class leader in lightness. “All components on the bike have been reduced to the essential according to KTM’s purity brand values,” says Simke. “But customers should rest assured that this bike will be amongst the best-equipped in the middleweight segment. We call it ‘The Scalpel’ – a precise, lightweight, focused bike with one task in mind – slicing through the street, and leaving others behind. It will be the sharpest street weapon in our range – and we hope in the entire sector, as well.”

So KTM’s new parallel-twin engine is installed as a fully load-bearing component in a tubular steel trellis frame, whose stiffness has been tuned to deliver sharp, precise handling with a sporty feel, says Hager. “We have aimed to produce a good balance between agility and stability in turns, as well as good straight line stability,” he says. There’s a cast aluminium subframe which incorporates air intakes running beneath the seat to the airbox, and Simke says KTM has aimed to target the seat height to as wide a range of statures as possible. High end componentry on the 790 Duke includes radial brakes, obviously with Bosch ABS as standard to meet Euro 4 homologation, and fully adjustable WP suspension with an upside down fork and a direct-action cantilever rear shock operated directly off the cast aluminium swingarm, and a WP steering damper. 10-spoke lightweight cast aluminium wheels are standard. There’s a very distinctive fluted silencer to the 2-1 stainless steel exhaust system with the hefty box under the swingarm pivot containing the three-way catalyst. All the lights front and rear are LED, with a distinctive headlight design that you must try to imagine, festooned as it was with heaps of black tape on the prototype by way of disguise, and there’s a full colour TFT dash similar to the one on the 690 Duke, plus there are illuminated menu switches. 

The 790 Duke’s extensive array of rider aids includes three riding modes – Sport, Street and Rain – plus multi-stage MTC traction control, Bosch Cornering ABS that’s also lean angle sensitive, as well as KTM’s established MSR/Motor Slip Regulation entailing targeted intervention by the Keihin ECU to mitigate engine braking’s effect on the rear wheel. The electronics package is likely to be a benchmark for the middleweight class, and besides the two-way powershifter also includes launch control and spin adjuster, as well as making the anti-wheelie programme switchable for those who want to stunt their way to the next traffic light. At the other end of the marketplace, there will also be an A2 licence-friendly reduced performance version.

The chance to try all this out for myself came in a brief 20-minute ride aboard the 790 Duke prototype on damp roads high up in the mountains surrounding Salzburg, on a private toll road overlooking Hitler’s former summer retreat at Berchtesgaden, the Eagle’s Nest. In spite of the bike having been caught on camera several times by biking paparazzi over the past couple of years, KTM was at pains to keep it all secret up until the last possible moment. But I was anxious to find out for myself even on such a short ride if the 790 Duke was indeed what I thought it might be the first time I started to dig out some details on it, and that’s a modern equivalent 20 years on of the bike I raced for three full seasons in 1995-97 with sufficient success that it’s become an iconic motorcycle for Yamaha TRX850 enthusiasts around the world. Yes, the unique Over-developed semi-works parallel-twin TriXie Yamaha I raced for Yamaha Europe, winning the 1996 Daytona Formula 1 ProTwins race, as well as the 1997 Sound of Thunder World Series.

Well, TriXie lives again, but in an Austrian dirndl dress rather than a Japanese kimono, and that’s immediately evident the moment you climb aboard and thumb the starter motor, for like its Yamaha antecedent which invented this format, the KTM has a 270º crank which delivers an offbeat lilt to the ultra-distinctive flat, droning exhaust. What’s more, equipped with copious rider aids including TC that the Yamaha never had, the KTM was totally at home in the slippery conditions – though you had to take care not to get too enthusiastic with the front of the pair of Maxxis Supermaxx ST tyres KTM had fitted to the bike. I’d never ridden on these before, but they seemed to heat up well in the foggy, dampish conditions, and there was good feedback from the front one via the well dialled-in WP fork.

The 790 Duke has quite an upright stance, more streetrod than streetfighter in the sense that it’s not a superbike with the bodywork stripped away, but rather a specifically tailored, sharp-steering package in its own right. By the way, at a projected price of around Euro 9,000 (horsepower, torque, engine dimensions and price were all TBA by KTM at the time of my ride, but the likely target price is indeed just under that figure) the KTM will be up against the new Indian-made Harley-Davidson 750 Street Rod selling for an ultra-affordable $8,695 in the USA. This market sector is indeed getting crowded, as Gerald Kiska stated – and that’s before the projected Husqvarna 790 Café Racer using the same motor joins its KTM cousin in the lineup, as more than one KTM staffer revealed is on the cards. Where do I sign??

But the 790 Duke is a very different package than the Harley with its flawed riding position and other ergonomic quirks. Instead, the Austrian parallel-twin is indeed a twin that thinks it’s a single, whereas another of its key rivals, the BMW F800R that’s also a parallel-twin, is much more half a four. You have trouble actually seeing that the 790 Duke indeed has two cylinders, not just one, and that visual conundrum is duplicated when you hop aboard and start riding it hard. For it feels so light and agile to flick from side to side climbing twisty mountain roads, even though the new KTM engine runs forwards to save on bulk, weight and power loss, according to Hager, resulting in an additional gyroscopic effect to the crank rotation which ought to heavy up the steering, but doesn’t. KTM has opted for this format because this way there’s no need to waste power driving an extra jackshaft to reverse the rotation of the crank, just as featured on another of its rivals its MV Agusta F3 800 triple whose crankshaft runs backwards, like all MotoGP bikes racing today. The 180/55ZR17 Maxxis rear tyre will be another factor in the nimble handling, too – KTM has resisted going large there, and heavying up the steering as a result. Interestingly, though, there’s a WP steering damper fitted as standard to the 790 Duke, which makes me wonder if the undisclosed chassis geometry is actually quite radical, in turn delivering that nimble, agile steering?

The flat-set handlebar gives great leverage for carving corners from side to side, and the KTM is indeed practically intuitive – yes, it’s the right word – in the way it steers into a turn. I’d be surprised if the dry weight of the bike is more than 150kg when it finally gets revealed – and that will be a factor too in the way the 790 Duke accelerates so well. The engine is a true flexible friend, with heaps of personality just like TRiXie – it pulls wide open in top gear from just 3,000 rpm, all the way to the 10,800 rpm limiter. There’s a slight moment of roughness around 7,000 rpm which I wouldn’t really characterise as vibration, but at all other revs it’s willing and torquey, with just enough vibration left in via the dual counterbalancers to make you feel you’re riding a motorcycle, not a sewing machine. Same thing with the settings for the slipper clutch, which has just enough engine braking left dialled in to help you stop for a second-gear hairpin from high speed, without chattering the rear wheel on the overrun. “We did this deliberately to add some personality,” admits Simke, “but the problem was knowing how much to leave in! I’m glad you like it.”

That I do – and although the radial brakes work well enough in spite of being supplied by A Company Other Than Brembo (KTM won’t say who!), the settings for the clutchless autoblipper are so ideally chosen that you hardly have to use them climbing a twisty mountain pass like this one – just backshift a couple of times for a slow bend, and the residual engine braking invariably takes care of slowing the bike in normal use – OK, start going for it, and you’ll need to work the lever, but not otherwise. The clutch action is super light and positive when you do have to use it, as I imagine you’d have to riding in town. This won’t cramp up your left hand riding the 790 Duke to work each morning, 

Normally when I’m privileged to be allowed to ride bikes like this still in prototype stage, I don’t get to go on the press launch proper. But this time I’ve asked KTM to include me on that, because this is such a good motorcycle I can’t wait to ride it for much longer and, presuming dry roads, harder. This is a very good motorcycle that sets the bar higher for its rivals in that crowded middleweight category, and it’s in every way a true KTM, as well as a modern reincarnation of TRiXie Yamaha two decades down the line.

Some stopgap filler!

 

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