It's only been a year since KTM finally took its long-awaited first step into tarmac territory with the RC8, the first fully-faired sportbike produced by the Austrian kings of the off-road world. Acclaimed for its real-world rideability and pinpoint-precise handling, in the eyes of some the RC8 still came up short in terms of its 1148cc 75-degree V-twin eight-valve motor. While quicker-revving and more than able to keep up with its desmodromic competition in the midrange, the KTM started to run out of breath when the rpms headed for the upper reaches of the tachometer.
"When we started out developing the RC8, the plan was to produce the perfect road bike, not the perfect racer," says KTM's Head of R&D Philipp Habsburg, one of the many youthful executives at the Austrian manufacturer. "This may sound as if it goes against our `Ready to Race' philosophy, but in seeking to establish KTM as an on-road manufacturer, we focused on producing the engine and the chassis characteristics for the RC8 that made it a great ride on the street, not so much the race track. We had to prove that we could make sporting streetbikes to a high quality level of manufacture and real-world performance. But it was always planned to do a race bike next, and this is the RC8R we launched last November at the Milan Show--which is indeed `Ready to Race'!" KTM plans to build just over 1,000 examples of the new model in 2009--by no coincidence, the minimum needed for Superbike homologation. And KTM will also offer the "Club Race Kit" which delivers an extra 10 horsepower and a 12 percent increase in torque over the already more powerful RC8R engine.
The chance to spend a day riding the RC8R on Portugal's challenging Portimao circuit certainly provided some answers as to how serious KTM was about challenging the established manufacturers as well. My numerous laps of track time included a tantalising 15 or so aboard the Austrian company's prototype Red Bull-sponsored factory RC8R Superbike, to be raced in the German IDM Superbike series this coming season as a possible prelude to joining the World Superbike Championship in 2010. After riding both bikes, I'm pretty certain that KTM is going to surprise quite a few of its rivals this coming season.
Hopping aboard the RC8R showcased the low 805mm seat that--like the now black-anodized footrests that can be raised by 20mm and fully adjustable hand controls and foot levers--was an immediate reminder of the KTM's well-thought-out design. Your knees tuck in so tight to the carefully shaped 16.5 litre fuel tank that you feel like you're riding a single-cylinder machine. The riding position is low and spacious with lots of room to move about the bike; instead of having your backside parked up in the breeze and your arms and shoulders feeling as if they've been doing push-ups all day, the RC8R represents a different approach to sportbike ergonomics that's less tiring to ride. The RC8R is a good bike for the long haul - KTM should think about going World Endurance racing with it!
The reduced gyroscopic effect of the lighter Marchesini forged aluminum wheels surely contribute to the stellar handling and agility of KTM's tubular steel frame package. And this is even with the decision to lengthen trail to 97mm from 91mm via reduced fork offset to improved stability. Weight was a key issue with the RC8R. "Our special Marchesini wheels are very light," says project leader Wolfgang Felber. "Plus we use Pirelli tires not only because they have good grip, and are the World Superbike control tire, but also because they are so light, about 2.7 pounds less than the competition. After extensive testing, we also found that they are also the best for durability and grip. And at the start of the RC8 project we were working with 48mm WP forks, but even on the RC8R we went back to the 43mm design we've launched the bike with, because it saves us 3.3 pounds of weight. Every little bit is important." Added up, the RC8R scales in at a claimed 401 pounds dry (all fluids except fuel), almost five pounds lighter than the RC8.
However, you can't help but notice the single biggest improvement on the new KTM, and that's the significant extra drive you get out of turns compared to the RC8. With one eye on the 1200cc twin-cylinder capacity ceiling for Superbike and Superstock racing, KTM enlarged the bore of the base model's 103mm Nikasil-lined cylinders by 2mm, using forged Mahle three-ring pistons with extensive ribbing and an incredibly short skirt to reduce friction and weight. This comes with no risk of piston slap, insists Habsburg. "With an unchanged 69mm stroke, we use the same crankshaft and crankcases as the RC8," says Habsburg, "but the new trapezoidal forged steel conrods are stronger, with wider contact areas for the small-end pins to support the bigger pistons, as well as accept the extra engine load from the higher 13.5:1 compression, one point more than the RC8." The 105mm pistons bring the RC8R's displacement to 1195cc from the RC8's 1148cc.
The RC8R's upgraded four-valve cylinder heads have a more compact combustion chamber and altered porting for better flow, yet employ the same 42mm titanium inlet/34mm steel exhaust valves as the smaller-bore engine, each still carrying just a single spring. All-new camshafts with altered profiles delivering greater duration but unchanged lift also boast adjustable cam sprockets, which allows valve timing to be changed, useful in optimizing performance for Superstock racing, or any Superbike class like the German IDM series that require retaining some of the stock engine internals.
Nestled between the cylinders...
Nestled between the cylinders of the 75-degree V-twin engine, both the RC8R's water pump impeller and housing have been redesigned for improved flow to work with the larger radiator and shed the more powerful engine's increased heat.
All this lifts the claimed power of the RC8R to 170 horsepower at 10,250 rpm, a 15-horsepower hike over the RC8 but 250 rpm higher. Torque is also up to 90.7 ft/lb at 8,000 rpm (versus the older bike's 88.5 ft/lb at the same rpm). The extra heat generated is shed via a side-mounted oil heat exchanger, and larger coolant radiator with a redesigned water pump to increase flow.
Because we didn't ride the RC8R on the street, I can't say if the extra power has made a difference as far as its worthiness as a streetbike. But I'd guess it has, mostly because of the linear way in how the RC8R delivers its extra horsepower all the way through the powerband. Just as on the RC8, it starts pulling well from as low as 4000 revs, heading hard and strong for the 10,700-rpm rev-limiter with no steps in the power delivery. On the RC8, this smooth power delivery made the KTM seem not as exciting as its Italian rivals, but the RC8R's more aggressive character has certainly addressed that. Thanks no doubt to the one-point higher compression ratio and small 52mm throttle bodies held over from the RC8, as well as the new cam profiles, there's a real sense of the bike lunging forward out of turns. This is a thrilling bike to ride hard.
Even though the bore is 2mm...
Even though the bore is 2mm larger, the RC8R's cylinder head features a smaller combustion chamber that works with the forged Mahle piston to boost compression ratio from 12.5:1 to 13.5:1, a significant increase. Valve sizes for the titanium intake and stainless steel exhaust remain the same; new camshafts sport adjustable sprockets.
Brembo monoblock radial-mount...
Brembo monoblock radial-mount calipers grip 320mm discs on the RC8R's front brake system, providing supreme stopping power. Forged aluminum Marchesini wheels are lighter than the RC8's items for less unsprung weight, as are the Pirelli Diablo Supercorsa tires. WP fork features titanium aluminum nitride coating for less stiction.
Like the RC8, the RC8R's valve...
Like the RC8, the RC8R's valve train uses finger followers to actuate the valves. This allows high rpm potential, although it also adds reciprocating valve train weight as well as bulk to the cylinder head casting.
Ironically the RC8R is actually more controllable despite that extra power than its standard sibling. For instance, I've never had a problem with the RC8's gearbox, but KTM's transmissions upgrades (a reshaped gearshift arrester star introduced last September as a no-charge update) have improved its action considerably. Without a side-by-side comparison, it's impossible to tell how this performance stacks up against its Ducati rival, but from a seat-of-the-pants feeling I'd say the new KTM might now have the edge on bottom end and midrange acceleration--and it especially isn't as wheelie-prone as the Italian bike--but isn't quite as fast on top end. The revised twin counterbalancers (to take account of the RC8R's bigger pistons and different rods) seem to do an even better job of ironing out vibration from the 75-degree V-twin motor. The few extra tingles noticeable through the footrests once you revved the smaller-engined RC8 above 8000 rpm have now gone, another factor in making this bike less tiring to ride hard on.
The 42mm titanium intake and...
The 42mm titanium intake and 34mm stainless steel exhaust valves (identical to the RC8 units) still utilize single valve springs to cut down on frictional losses and valve train weight.
The KTM's transmission received...
The KTM's transmission received some subtle modifications, including the same reshaped gearshift arrester star that was an post-release update on the RC8, and revised engagement dog shape for the gearshaft pinions to avoid premature meshing. There is no slipper clutch in the RC8R gearbox, with an ECU-activated throttle bypass providing back-torque limitation instead.
In order to transfer the additional...
In order to transfer the additional heat generated by the more powerful engine, a liquid-cooled oil cooler was added to the RC8R engine.
Although the Keihin single-injector ECU is ideally mapped, with none of the abrupt pickup off a closed throttle that the RC8 sometimes displayed, KTM has provided two different throttle grip tubes with the bike, each with a different profile (no ride-by-wire yet, but KTM admits to working on it for the future). The "Race" version that comes standard has the usual circular arrangement, which delivers instant response without lacking control. The "Road" version has an eccentric cable pull that gives around 10 percent slower response until about half-throttle where it reverts to normal. It works, too; even though I didn't have any wet roads to ride on, I can imagine how this would be beneficial on slippery surfaces, or just for everyday street riding, because it makes the throttle pick-up quite a bit smoother and less aggressive.
The new KTM is a very reassuring bike because you feel in control even when riding close to the edge. The front tire feels planted on the tarmac, helped no doubt by that 54/46 forward weight bias that is quite atypical by V-twin standards. This gives you the confidence to use those fabulous Brembo radial-mount monobloc brakes (featuring 0.5mm thicker discs to help alleviate heat concerns with the RC8R's more aggressive racetrack intentions) to dive deep into turns and trailbrake toward the apex without any sign of instability. That's where the lack of a slipper clutch is cleverly masked by the RC8R's Keihin ECU mapping. By slightly opening one throttle butterfly valve on the rear cylinder, the system bleeds off engine vacuum to overcome the effects of engine braking while retaining most of the benefits.
As satisfying as the RC8R's engine performance undoubtedly is, it's difficult not to get excited about its fantastic handling. Even with the increased power, you can position the KTM almost at will in all areas of a turn, making it seem smaller than it really is. Its overall agility is unrivalled by the V-twin opposition, with less effort required for steering inputs, and I doubt the RC8R will have much to fear in the tight stuff from any four-cylinder superbike contender. The fully adjustable WP suspension is literally almost infinitely variable, and the RC8R can be set up to suit practically any rider's weight, riding style, or stature.
There really is little to complain about on the new KTM, but if we're getting picky I still think the digital dash whose various displays are accessed via your left forefinger on the Mode button on the front portion of the left clip-on switchgear is a triumph of design over legibility. While the large digital speedometer reading is easy to pick up, the bar-graph tachometer across the top is much less so, and there's too much data on the screen to take in when you're really going for it, not helped by the script and the unit itself being too small. Plus, the two things you'd really like to know are still missing from it: there's no fuel gauge, and no gear indicator, especially with such a smooth, linear power delivery and flat torque curve that can be so deceptive. These oversights from the RC8 should have been corrected on the new bike.
Of course, there are still numerous neat detail touches on the RC8. These include the quick-change rear wheel system worthy of an endurance racer, all that ergonomic adjustment to help you find the ideal riding position, the high- and low-speed compression damping on the WP shock, the eccentric ride height adjuster, the built-in tank sliders that come standard, the quick on/off passenger seatpad and footrest hangers, the equally easy-off mirrors, the detachable rear license plate hanger, the grippy footpegs, the ultra-distinctive lights front and rear; just look at it closely and you'll find more. It's bling that delivers--form matched by function, all wrapped up in the most individual of styling packages--all with a really rewarding step up in performance compared to its predecessor. And KTM's build quality seems to have taken another step up with the RC8R, which if it were from an Italian manufacturer would have everyone raving about how superlative Latin design is, and how sexy all those trick components are. Well, Austria is Italy's northern neighbor, after all.
'09 KTM RC8R
Type: Liquid-cooled, 75-degree DOHC 4-stroke V-twin
Bore x stroke: 105 x 69mm
Compression ratio: 13.5:1
Induction: Keihin electronic fuel injection, 52mm throttle bodies, single injector/cyl.
Front tire: 120/70ZR-17 Pirelli Diablo Supercorsa
Rear tire: 190/55ZR-17 Pirelli Diablo Supercorsa
Rake/trail: 23.3 deg./3.8 in. (97mm)
Wheelbase: 56.3 in. (1430mm)
Fuel capacity: 4.3 gal. (16.5L)
Claimed wet weight: 401 lb. (182kg), all fluids except fuel