KTM LC8 950 beginnings CJ Designs LLC Blog

7 Jan 2015 | Author: | Comments Off on KTM LC8 950 beginnings CJ Designs LLC Blog
Bimota SB 6 R

KTM LC8 950 beginnings

Seeing as we just got hit by lots of snow around the midwest.  I’m sure many of us will need a good sit to relax those sore muscles.   While many dream about the New 1190 Adventure, how about some worth while reading material to touch up on your KTM knowledge.

So go grab a nice drink and take a load off.

“Aug 2002″

After the first press voices concerning the riding impressions on the 950 Rally prototype in the april newsletter, it is now the job of Alan Cathcart, former street-racing champion, now freelance journalist with international reputation, to add not only his impression of the new model, but also giving you detailed background information of the LC 8 engine:

Not Like The Others

from Alan Cathcart

Although it’s only in September this year that KTM’s LC8 liquid-cooled dohc eight-valve 75-degree V-twin engine will be presented for customer purchase – initially in the 950 Adventure customer replica of Fabrizio Meoni’s Dakar Rally-winning prototype, to create a two-wheeled equivalent of the Subaru WRX or Mitsubishi Evo 7 rallycar, then later in 2003 in the V2 Duke streetrod – the Austrian kings of the off-road world have been thinking for most of the past decade about how to expand what until now has been exclusively a single-cylinder dirt-derived model range, into twin-cylinder tarmac territory.

Those plans first found expression shortly after KTM boss Stefan Pierer and his colleagues took over the insolvent company early in 1992, and began the spectacular turnaround which has seen KTM go from bust to boom in less than a decade. That year, a one-off special called the Bepono, built for the German BoTT series by two engineering students by combining a pair of cylinders from a KTM LC4 single on a special crankcase, was displayed on the KTM stand at the Cologne Show.

That was just a teaser, though – as was the second time around in 1996, when the company’s stock market flotation prospectus and investor meetings were spiced up by the revelation that the Stuttgart-based design office Kraft Technik, had been commissioned by KTM to produce a design for a V-twin Hard Enduro, possibly using the 60-degree V-twin RSV900 engine Rotax were then developing for Aprilia. The Italian company however refused to share it with their Austrian neighbours, even for an off-road bike – and in any case decided at the last minute to redesign what had originally been conceived in 1994 as a 95mm-bore direct 900cc V-twin targeted at the CBR900RR Honda FireBlade, then topping the sales charts, by taking the decision in early ’96 to increase capacity to a full 97mm-bore 1000cc, so costing Aprilia owner Ivano Beggio a reputed extra $2.5 million for the privilege of creating what was effectively a new engine – though he could at least now go World Superbike racing with the result in spinoff SP form.

Another alternative for KTM was the Swedish Folan 60-degree V-twin motor which already existed, consisting this time of two Husaberg cylinders on a special crankcase, albeit without provision of any balance shaft to eliminate the considerable resulting vibration. Even though KTM by now owned Husaberg, this, too, was aborted once KTM had been successfully floated on the stock market.

But in early 1998, as the company grew in strength and the need to expand its hitherto single-cylinder range with a twin-cylinder product line became a priority, Pierer commissioned chief engineer Wolfgang Felber to make preliminary studies of twin-cylinder engine formats and vehicle concepts. “Our idea wasn’t so much to build a better V-twin, but to develop a versatile twin-cylinder engine concept, which had the potential to be used in off-road bikes as well as on the street, without any compromises in either application,” says 39-year old Felber, himself a former 250cc Grand Prix road racer on Rotax tandem-twin two-strokes, then German Supermono champion with his self-built, self-tuned KTM Single Racer. “In fact, we made studies of several other concepts, including not just many kinds of V-twins but also some that might seem a bit strange, like a horizontal as well as vertical parallel twin, crossways and lengthways Boxer motors, and even a tandem-twin like the 250 GP bike I used to race! But eventually we concluded that a 75-degree V-twin was the best option, especially in terms of following KTM’s established policy of going racing successfully first with a prototype version, then bringing an identical product to the marketplace in succeeding years. Plus, it had the extra advantage that we could build a V-twin not like the others!”

Indeed, for compared to a 90-degree format as practiced by Ducati, Honda and Sukuki, the 75-degree layout offered a more compact layout, which in turn allowed KTM to place the engine wherever they wanted in the chassis, without any compromises, while the 60-degree option as preferred by first Harley-Davidson, then Aprilia, presented potential difficulties with intake design and throttle body location (too narrow to get a straight hit at the valves), and especially vibration. “We would have needed to instal twin counterbalancers, as Aprilia has done, and this was not acceptable either in terms of power loss or, particularly, weight,” says Felber. “But we also wanted to make sure there was no lost space in the engine, and so to meet the demands of what we called our ‘box measurement’ – assessing how small a box would be needed to contain the entire engine and throttle bodies – we decided the best solution was to place the electric starter between the cylinders, as well as the balance shaft and water pump, for which we needed more space than on a 60-degree or even a 72-degree V-twin angle like Voxan’s. It’s only a matter of millimetres – but compare this to an L-twin like a Ducati, and you can see the benefits of focusing on this, in terms of bulk and installation.”

So by August 1998 the decision was made to go with a 75-degree V-twin design, but with special emphasis on light weight and, especially, compact build. To do so, KTM decided to assume the entire RD process themselves in-house, and hired Claus Holweg as Project Manager for the LC8, fresh from their Austrian rivals, Rotax, where he had headed up the RD team which had developed the freshly-launched RSV Mille engine for Aprilia – so he already had several years of accumulated V-twin expertise under his wings, helping in turn to keep the KTM V2 learning curve as flat as possible, and to shorten the time scale for development. “My work on the Aprilia project was at an end, but I already had many ideas I wanted to put into metal in making a Mark Two V-twin that would be even better,” says Holweg. “My goal was to build the smallest, lightest and most powerful V-twin engine ever made, but at the same time to make it as safe as necessary in terms of durability. It was a very exciting engineering challenge.” One that was fulfilled with amazing speed: the LC8 engine went from a blank computer screen to its first dyno run on August 11, 1999 in exactly 12 months – a remarkable achievement, even if the first time it fired up was in total darkness, thanks to a Austria’s coincidental total eclipse of the sun!

How well Felber’s team succeeded in meeting their design targets may be judged by comparing the dry weight of the LC8 motor without carbs/throttle bodies, with that of its various V-twin competitors. The 75-degree KTM (fitted with a single balance shaft) scales just 56 kg. compared to 68 kg. for the 60-degree Aprilia/Rotax (complete with twin counterbalancers), 73 kg. for both the 90-degree Honda VTR1000 and Suzuki TL1000, 75 kg. for an old-style 90-degree Ducati desmoquattro engine (though 72 kg. for the new Testastretta design), and 76 kg. for the lightest version available of the flat-twin BMW Boxer motor – all with perfect primary balance, so no balance weights.

This makes the KTM engine between 17% and 26% lighter than its rivals, achieved moreover without extensive use of magnesium, which is confined to the cam covers – nowhere else, for fear of exposure to stone damage in off-road use. But add to that the Austrian motor’s ultra-compact build, and it’s hard not to applaud the extent of the RD team’s achievement in creating such an intelligent, rational, stripped-down design, without compromising reliability, or performance.

Winning the 2001 Egypt Rally first time out in the hands of Fabrizio Meoni, in the wake of an arduous 120,000 km. test programme, followed by the new 950 Rally V-twin’s dominant victory in the hands of the Italian works rider in the gruelling 2002 Paris-Dakar marathon, was proof of that. Nani Roma’s win in the Rally Tunisia first time out on the new bike, underlined its worth: three out of three ain’t bad for an all-new design!

The dry-sump LC8 engine is vertically-split, not only to save weight (no need for long engine bolts to hold everything together), but also as the easiest way of arranging the crankshaft and twin gearbox shafts on different planes to reduce the overall length of the engine, R1-style. The three-litre oil tank doubles as the oil radiator, positioned ahead of the front cylinder, with twin oil pumps mounted on a single shaft located beneath the multiplate oil-bath clutch – a wet-sump engine design was never considered, because of the 10 cm/4 in. reduction in ground clearance this would entail, unacceptable for off-road applications.

In any case, the oil supply to the engine is maintained when the bike is lying on the ground and the engine running – even more important when the rider is, er, prone to error on the Sahara sand! The twin dohc four-valve cylinders are evenly located on the crankcase, not rotated as on a Honda or Suzuki V-twin: “I did a lot of experimentation with wheel clearance and weight distribution,” says Felber, “and it turned out this format allows 300mm of front wheel travel on the Rally bike, as well as an ideal configuration for the oil tank, radiator, everything. But we also looked from the beginning at a street application, and on the Duke with shorter forks, less travel and a 17-inch front wheel instead of a 21-inch one on the off-road bike, we were able to shorten the frame and improve front end weight bias, as well as lowering the centre of gravity by placing the battery in the lost space in front of the engine, all without compromising wheel clearance.”

The LC8 uses a forged, one-piece plain-bearing crankshaft weighing less than 5 kg. – so, lighter than one from KTM’s own LC4 single, and more than 3 kg. less than a Suzuki TL1000 bottom end, for example – with small, semi-circular flywheels, and short H-section forged steel conrods measuring 125mm in length and mounted on a common crankpin. These carry three-ring Mahle pistons which once again are forged, and weigh 378 grams each without bolts, deliver 11.5:1 compression, and have a flat top and short skirt: total height of the piston is just 46mm. “For sure we lose a little by having such a light crank,” admits Felber, “but from the beginning we tried to create a very responsive engine for sports bike application – doesn’t matter whether it’s a road bike or off-road bike, it’s the same.

Due to the fact we have a very short stroke and very small crankshaft, we put a lot of effort into ensuring it ran smoothly and had good torque at low rpm. We use the same-size flywheels on the off-road carburettor version as on the fuel-injected roadbike version.” The crank carries a spur gear on the left side driving the multi-purpose layshaft positioned between the cylinders, whose five-function design is typical of the refined rationality of the LC8′s design. Thus, it not only carries the twin opposed counterbalancer weights needed to eliminate the primary vibration endemic in a 75-degree V-twin, it also drives the water pump and centrifugal engine breather, as well as acting as an idler wheel for the starter motor, and the composite chain and gear drive to the twin overhead camshafts A six-speed transmission with gear primary drive is employed on all versions of the LC8 – no five-speed for off-road use, though internal ratios and overall gearing will be varied according to the application.

Bimota SB 6 R
Bimota SB 6 R

Unlike on the Bepono project bike a decade ago, the LC8 employs all-new four-valve cylinder heads rather than a pair of those from KTM’s existing singles, fitted with bucket tappets and steel valves (38mm inlet and 33mm exhausts), each with double valve springs and sitting at a total included angle of just 22 degrees – very flat, in accordance with best Formula 1 principles. Viewed from above, the steep downdraught and knife-edged divisions of the intake ports is really noticeable, giving a very straight hit at the inlet valves. “Our main target for design of the cylinder heads was always to maximise compactness by having the smallest possible drive gears on the camshafts, as well as a camdrive mechanism capable of very high revs,” says Felber. “We wanted to avoid having the very large camwheels needed to achieve a 2:1 ratio with direct chain drive, like on a Honda Varadero.” For this reason, the LC8 employs very short hydraulically-tensioned offset camchains, driven off sprockets mounted at either end of the multipurpose layshaft.

These run to an intermediate gear located in each cylinder head, which in turn drives the two small camwheels at the end of each camshaft. The camdrive layout is broadly similar to that of the Suzuki TL1000 (and before that, of the Rumi Supermono single), but is far more compact in every direction.

In prototype 950 Rally/Adventure form, as well as the V2 Duke guise in which it will make its tarmac debut at Intermot in September, the LC8 engine measures 100 x 60 mm for a capacity of 942cc, but the design was conceived to accomodate various capacities ranging from 800 to 1000cc – there’s room to increase the bore up to 103 mm, for example, making an even shorter-stroke 999cc Superbike version a realistic option, for example: the engine is designed to be capable or producing up to 180 bhp at the crank, says Claus Holweg, and to rev up to 12,000 rpm safely. And while Meoni’s Dakar-winning dirt sled and its 950 Adventure customer clone kicking off KTM’s V-twin production this fall both employ 43.5 mm Keihin CV carbs and a Denso CDI, with the carbs fitted inside the substantial airbox to liberate extra space under the seat – a first in motorcycles, says designer Claus Holweg – KTM will use fuel-injection and a fully-mapped engine management system on the V2 Duke, being developed in conjunction with a proven supplier who is however new to EFI, with throttle bodies ranging from 48mm to 52mm in diameter (final size has yet to be chosen) and a single injector per cylinder, located beneath the throttle butterfly. In this first tarmac application, power from the 942cc engine will rise to around 120 bhp at the crankshaft, says Wolfgang Felber, compared to the current output of the carburetted off-road engine of 102 bhp at 8000 rpm, which produces maximum torque of 97 Nm at 6000 rpm, with a very linear curve.

Though the engine has the swingarm pivoting in the crankcases (as well as in the frame) for extra rigidity, it’s not a stressed chassis member. “We didn’t want to have this because in off-road use we have controlled deformation of the frame in order to reduce rider fatigue,” explains Wolfgang Felber, “and if you use the engine as part of the chassis in such a situation, it risks problems with the base gaskets and cylinder head gaskets, and so on – even maybe cracking the castings unless you make them very strong, and so heavy. The engine increases the torsional stiffness of the frame by around 30%, but it’s not a load-carrying component in the frame.” But the LC8′s compact design not only permits greater freedom of choice in positioning the engine in the frame, as on the similar-concept R1 it also allows a very long swingarm, for improved traction and grip on the V2 Duke, while the 25mm even longer one on the 950 Rally/Adventurer delivers crucial high-speed stability on loose surfaces and especially in sandy conditions. “I see a motorcycle as a total package,” says Felber. “It’s not enough to have just a good engine or a good chassis, but to work together to make an effective entire product. Here at KTM we always make sure our engine designers and the frame builders work together all the way through the project, not just have occasional meetings to let each other know what’s going on! It’s the only way to be sure you have the most effective design as a whole.”

Fair enough – but after seeing the fruits of KTM’s efforts so far to build a better twin, and the success of their engineers in making a proven effective package for off-road use, it’s hard not to believe that this is a Superbike engine in the making. The LC8 motor has all the attributes in terms of architecture, weight and potential performance to allow the Austrian company to produce a 250 GP-sized sportbike weighing well under 180 kg. but with more than 130 bhp available in street guise.

Or, there again, they could make a deal with Buell and stick an ultra-modern, ultra-compact eight-valve V-twin engine in the new Firebolt with its innovative chassis design of similar description! That would be some package – but perhaps in the meanwhile, KTM might do something similar themselves, so as to go Superbike racing with the result, while working all the time on their future 75-degree V4 MotoGP contender – and prototype four-cylinder sportbike? Don’t bet against it…..


Born in Wales, married to Stella, with three children, lives in central England, near Stratford-upon-Avon, Warwickshire.

Law degree from Cambridge University, speaks five languages, formerly worked in travel industry as Director of UK’s largest specialist incoming tour operator, before becoming full-time syndicated freelance motorcycle journalist in 1981, with articles now published in more than 30 countries. Frequently requested by many leading motorcycle manufacturers such as Ducati, Honda, KTM, Aprilia, Bimota and Triumph to evaluate and comment on their significant new models before launch, both as test rider and industry observer, and to write detailed feature articles on their development to coincide with their public debut. Only journalist permitted by all major factories in Japan and Europe to test ride their works Grand Prix and World Superbike machines.

Has ridden motorcycles since age 14, but firstly raced cars before swapping to bikes in 1973. During 25-year racing career won the Australian TT twice (Bathurst), Daytona ProTwins three times, Daytona F750 once, and twice finished runner-up in the European Supermono Championship run alongside the World Superbike series, as well as fourth, fifth and ninth in Isle of Man TT.

Winner of 1997 Sound of Thunder World Series (for Yamaha) and British Supermono Championship (Ducati); 1996 BEARS World Series (Bimota); 1993 Dutch Open and Japanese Grand Slam Supermono Championships (Ducati); 1979 British Single-Cylinder Championship (Aermacchi Harley-Davidson). Founder with wife Stella of the Classic Racing Motorcycle Club, and International Historic Racing Organisation – each the largest organisation of their kind in the world – and today Honorary President of each one.

Winner of the Guild of Motoring Writers ‘Pierre Dreyfus Award’ in 1992 for top motorsport journalist (cars and bikes). Winner of the Guild’s ‘Rootes Gold Cup’ in 1986, 1987, 1992, 1993, 1994 and 1997 in recognition of outstanding achievement by a car or bike journalist in the world of motorsport. Hobbies are classic cars, films, country rock music, wine and good food.

Bimota SB 6 R
Bimota SB 6 R
Bimota SB 6 R
Bimota SB 6 R
Bimota SB 6 R
Bimota SB 6 R

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