There's a new kid on the block in the pavement arena of the motorcycle industry. And while he's not exactly a threat to the neighborhood bullies at the moment, taking a look at his past deeds might give them some cause for concern in the not-too-distant future.
Austrian manufacturer KTM has carved out a sizable chunk of market share in the off-road portion of motorcycling, and it's accomplished this with solid engineering, aggressive marketing and a fierce competitive instinct. As a possible precursor of things to come, the company entered the 125 Grand Prix Roadracing World Championship in 2003 after a long history of successful off-road racing exploits and then followed that up by officially entering the 250 GP World Championship in 2005. Behind-the-scenes snickering at the orange bikes soon fell silent when the KTMs rapidly established themselves as serious competitors with numerous race wins in both classes. After quickly adapting to the four-stroke movement in off-road motorcycle design, the company even developed a 990cc V-four pneumatic valve engine used by Kenny Roberts' Team KR machines in the premier MotoGP class in 2005, but the project was abruptly shelved midseason due to cost concerns.
The forthcoming RC8 V-twin sportbike we previewed in a previous issue ("Austrian Attack," June '08) is the latest road-going product from KTM and aptly demonstrates how serious the company really is about the pavement market sector. Prior to the RC8, however, KTM's street lineup was limited to mostly supermoto-style machines, along with the single-cylinder 690 Duke and 990cc V-twin Super Duke, the latter of which we last tested in our naked-bike group test ("Naked & Naughty," Sept. '07). We were impressed with-although not overly excited about-the Super Duke's combination of peppy engine and nimble handling, with most of our testers agreeing the KTM was the most fun to ride in that group.
So when the '08 Super Duke R rolled into our shop, a cursory look at the carbon-fiber bits and upgraded wheels and suspension had us thinking the R was basically a dressed-up standard Super Duke. How wrong we were. . . .
Much More Than Skin-Deep
The 999cc, 75-degree V-twin engine received numerous internal upgrades aimed at boosting top-end power without compromising the KTM's superb low- and midrange grunt. Up top, the cylinder head underwent a thorough revamp, starting with larger intake and reshaped exhaust ports to help improve flow. The bigger intake ports are a perfect fit to the 3mm-larger intake valves (now 41mm), now titanium instead of steel. The same NHK single-valve springs fitted to the RC8 are used in the Super Duke R, in conjunction with the lighter valves, allowing the rev limit to be increased from 9500 rpm to 10,250 rpm. Coolant passages inside the cylinder head were redesigned to work with the new water pump (using a more efficient curved impeller) for improved flow and cooling, especially around the exhaust-valve area.
Contributing to the higher rev limit are revised pistons and connecting rods that have been trimmed of an undisclosed amount of reciprocating weight. Each 101mm piston features a DLC-coated pin that permits a smaller diameter to be utilized, cutting weight from both the pin and the piston itself, because the surrounding material in the piston can be reduced. The rods have been slightly redesigned, with a reduction in big-end bearing size paring both weight and friction. The crankshaft counterweights and single counterbalancer have been somewhat reshaped to work with the lighter pistons and rods, although no weight reduction is claimed.
The '08 Super Duke R features...
The '08 Super Duke R features reworked cylinder heads with larger intake and reshaped exhaust ports; larger, titanium intake valves; and a revised coolant-jacket design to accommodate the new water pump and provide improved exhaust-valve-area cooling.
In order to work with the...
In order to work with the lighter pistons, the connecting rods were redesigned, with smaller diameter crankpin ends reducing friction and reciprocating weight. Crankshaft counterweights were also revamped slightly, but no weight was removed.
A beautifully crafted, tapered-diameter,...
A beautifully crafted, tapered-diameter, stainless steel Akrapovic header system comes as standard equipment on the Super Duke R, a first for a production sportbike.
All of this inhales through a new Keihin EFI system with larger 52mm throttle bodies (up from the standard Super Duke's 48mm units) each using a single injector, identical to the setup fitted to the new RC8. Exhaled gases are handled by an exquisite tapered-diameter 2-into-1-into-2 stainless steel header system built by renowned exhaust manufacturer Akrapovic, the first time its handiwork has been made available as standard equipment on a production bike, according to KTM.
The chromoly-steel tube trellis frame and aluminum beam swingarm are basically unchanged from the standard Super Duke, although the 48mm inverted WP fork now has titanium nitride coating on the fork tubes for less stiction, and the WP rear shock has a slightly increased length that raises the rear ride height enough to sharpen the steering geometry's rake and trail from the standard Super Duke's 23.9 degree/103mm to the R model's 22.7-degree/93.9mm setup. An adjustable WP steering damper is included with the R to help keep the front end from getting nervous at higher speeds. For 2008 the 3.5 x 17-inch and 5.5 x 17-inch Marchesini aluminum wheels come shod with Pirelli's Diablo Corsa III rubber.