Cycle News - Archive Issues - 2000's

competition with each other, as much 998R now delivering an even broader as with Honda - and it's hard not to get the feeling that HRC's corporate spread of power for the coming season, and Aprilia sure to be working mind was elsewhere. Whether this will be the case again flat out to give new recruit Noriyuki Haga the means to win them the in 2002 remains to be seen - though the fact that Edwards will be Honda's world title they so badly crave with its RSV1000, HRC engineers will have to focusing their Superb ike attention on developing the forthcoming full one-liter CBR1000 into a surefire only factory rider in the coming sea- think hard about raising the rev limit contender for top honors when their engineers - by winning the son perhaps says it all. But with the ultra short-stroke 104-bore Ducati at least another 500 rpm for next season, to provide a more plentiful sup- World Superbike reinvents itself in 2004, and just concentrate mean- world title in its debut season? We shall see. eN !i3GDD D@)D[JiJ[i} @[JiJ Ilw@ !i3@&511 In defending the World Superbike title, Honda also pursued a parallel development program of the uprated version of the RC51 street version, which made its public debut at the Milan Show last September. This takes a leaf from Ducati's established policy of equipping their customer road bikes with the parts used by the factory Superbike racers as part of the homologated racekit - which then allows the company to homologate an entirely new race kit the following season for what is now counted as a new model. The fact that the RC45 V -four never took advantage of this R&D strategy may be one reason it had such a hard time beating the desmoquattros for the world title more than just the once - but now HRC has gone Latin, and is bringing to the street the performance modifications developed for, and on, the racetrack. Some might say that, in so doing, Honda has at last implicitly recognized the whole point of going Superbike racing in the first place - not just for sales promotion reasons, but for good old-fashioned customer R&D purposes, fueled, of course, by the desire to win. So, the bike on which Colin Edwards finished runner-up in the 2001 World Championship was dubbed the SP-2 (well, except for in the U.S. market) for promotional reasons, even if it's essentially the same bike as the SP-l. However, it also had many detail changes, says Edwards' Kiwi race engineer, Adrian Gorst, starting with the chassis rigidity that in the 2000 season the team came to realize was too stiff. To reduce this and make the bike 'talk' to the rider, the front engine downhangers are no longer cast but are instead fabricated, and the swingarm is completely different: "It might look bigger and stronger, hut it's actually weaker than the SP-1 roadbike one, which was very, very strong because it has do 100,000 miles and take a passenger, so it's actually too stiff for racing," says Gorst. "This now translates to the street market, because the SP-2 has the factory 2001 swingarm, complete with the scallop out for the pipe to come up the inside. It's much more of a basis for a customer racer with lights than a high-mileage roadbike - not just in this one way, but many others, like having the big 62mm kit throttle bodies we use, and so on." However, in racing nothing stands still, and in anticipation of what they knew would be a fierce fight by Ducati to regain the world title, as well as the challenge from Aprilia who by the end of 2000 had what many considered to be the fastest bike on the grid, Honda engineers tried to improve the dynamic performance of their 90-degree V-twin - only to suffer an embarrassing spate of high-profile engine failures at the start of the season. However, that wasn't because HRC engineers had tried for more power, says Gorst, but came about with a batch of faulty engine parts (you guess: pistons/conrods/valves/camshafts - HRC isn't saying) after they'd tried to change the engine's effect on the handling. ·We'd perceived that we didn't have enough engine braking with the SP-1, so that it wouldn't tum easily enough into the comer," S<'lys Gorst, "so we changed to a lighter crank for the first couple of races - but then decided this was a mistake, so we reverted to the original heavier crank." However, though you won't get anyone in the Honda team to comment publicly on this - remember that works Hondas never suffer engine blowups, only 'ignition failure' caused by the engine no longer rotating, and therefore unable to generate currentl - it seemed that both Edwards and Okada suffered engine problems in the first two races at Valencia and KyaJami related to the new crank, so that might be another reason the lighter version was dropped. And of course, such a component would also enhance acceleration hard on the gas, as well engine braking off it - and that was the main area of advantage that the Ducati still had in Honda's title year. The most externally obvious change to the VTR 1000SP2 engine package came at Oschersleben in September - after the mid-season break punctuated by the Suzuka 8-Hours, which Edwards won with teammate Valentino Rossi, aboard an SP-2 which delivered spin-off benefits to Honda's World Superbike contender, including the single-pipe exhaust. This improved the power delivery at the cost of a slight reduction in outright numbers: "It definitely makes it a bit more ride- while on providing a competitive V- ply of the top-end power the bike already has. And filling in the gap at the bot- twin package for their privateer customers and National-level teams, tom, too. Or will HRC prefer to start able - Colin said he was getting left off the corners by the Ducati, and we needed to eliminate the dip in the torque curve the engine had suffered from up till then, to keep up with them off the bend," says Gorst. Judging by Edwards' race win and close second place in Germany, it seems to have helped - but other season-long R&D on the Honda V-twin engine was confined to refinement of the existing package, with detail mods to combustion chamber shape, port design etc. But these combined to bring an 8 hp power increase over the 2000 title-winning engine by mid-season, 3 hp of which was then handed back again with the less potent but more user-friendly single-exit exhaust, which comes fitted with a carbon-wrap Akrapovic silencer. Still, that makes 186 hp at the crank at 12,000 rpm in the form I rode the bike at Jerez - not quite back to the output of the ultimate version of the V-four RC45, but surely delivered in a more usable and effective package. Moreover, apart from the failures causes by that faulty early-season batch of parts, last season the Honda underlined the robustness of its 180 hp-plus engine, especially by the standards of other, shorter-fused V-twin Superbikes of the Latin persuasion. "We're back up to 2500 km. 11550 miles] between stripdowns," says Gorst, "so thafs several races on the go before we need to pull it apart and replace anything, and we got 3500 km. [2170 miles] out of a set of crankcases before they made a detail modification which meant we had to replace them - last year, they lasted the full season, and so did crankshafts and cylinder heads." This robust engine life augurs well for the coming season when HRC at last promises to offer customers a similar level of performance to the Castrol Honda works racers - but it also explains the Japanese V-twin's amazing qualities as an endurance racer, even in the succession of eight hour-long sprint races which comprises the Suzuka 8 Hours. The SP-2's horizontally-split 90-degree V-twin DOHC 8valve engjne - still a wet-sump design as on all Hondas (and Ducatis!). compared to the dry-sump Aprilia RSV1000 - naturally follows the SP-1 (a.k.a. RC51 in America) streetbike in measuring 100 x 63.6 mm, for 999 cc, with camdrive via a train of three gears driven off the end of the crank, operating the twin overhead camshafts iT) each cylinder head. The big bore allows a set of oversize valves per cylinder, each with two valve springs and set at a flat included angle of 24 degrees to each other. These are all made from titanium, as are the connecting rods, and are fitted with three-ring pistons after Honda suffered oil blow -by problems in testing with two-ring ones. With oil consumption a factor in the Suzuka 8~ours, HRC engineers opted to stick with the three-ring ones in developing the race engine, which is essentially the same for both endurance and sprint racing. While the pair of Keihin throttle bodies fitted to the street SP-1 measure just 54mm, the works racers (and now the SP2 streetbike) use 62mm versions on their PGM Fl fuel-injection. specially homologated for World Superbike via the customer race kit. These incorporate twin injectors per cylinder, set opposite each other before the throttle butterfly, now with a fully integrated engine management system incorporating the EFI. The street SP- 1 airbox has been substantially increased in size via a kit part on the racer (and features as standard on the SP-2), still fed by the same triangular central airduct in the nose of the fairing. As on the streetbike, this flows air to the throttle bodies via ducting cleverly incorporated in the alloy steering head casting of the chassis, all aimed at delivering a straight hit of cool ram air to the airbox, while keeping the bike slim and aerodynamic. The SP-2 scales just over two pounds over the World Superbike 356.4 pounds half-dry weight limit, in spite of retaining the electric start on the racebike, split anywhere between 53/47 percent to 55/45 percent frontwards, depending on ride height, tire profile and swingarm length - which the team do alter a little from one circuit to another, but do try to run as long as possible to keep the weight on the front of the bike. But the Honda V-twin's chassis was essentially unaltered for 2001 over the bike's debut championship year, with the extruded/cast aluminum twin-spar design featuring the braced, double-sided, fabricated alloy swingarm pivoting in both the engine crankcases and the lower frame casting, which is also braced with an alloy cross-member. For 2001 the team had a new link for the Showa rear shock, with a more progressive ratio, but mainly raced with what they had the previous season. The fully adjustable 47mm Showa race preferring to regard their RCSl Superb ike project as mission accomplished at world level, having proved its worth - and the talents of forks are set in the frame at the stock 24.5 degree head angle, and Colin usually runs around 96-99 mm of trail quite conservative steering geometry by racebike standards, in keeping with his preference for stability, rather than ultrafast steering. Coming from the 125/250 GP classes, Valenti· no Rossi likes the same, so they can't have argued too much about chassis setup fOT the bike they shared to win Suzuka. The brake package sees 320mm front Nissin discs gripped by the Japanese firm's six-pot calipers, and a tiny 196mm disc that Edwards hardly ever uses. "We had the choice what brakes to use and both riders chose Nissin," says Adrian Gorst. "Tady'd never used Nissin in his life before as a works rider, always used Brembo - but he really preferred them. They stop very well, there's good feeling and never any brake fade, in spite of which they're standard race brakes, not even with a radial mounting." In 2001, Edwards always raced with the Michelin 16.5inch front tire fitted for our test, opting for its extra grip at the cost of slightly reduced feel from the front end compared to the now superceded 17-incher. At the rear, whereas previously he'd switched between both sizes in the dry, using the 17-inch tire that gives more grip but goes off sooner at some tracks where being able to accelerate harder on the angle is a key factor, in the season just ended he stuck with the 16.5incher, for extra durability. "But we have a lot of different rear tire profiles, so depending on which one he'd choose and on the nature of the racetrack, we'd switch between a six·inch rear rim, or a 6.25 or even a 6.13," says Gorst. "But we only raced a 17inch rear tire once, and it wasn't so great - just lacks every· where compared to the 16.5-incher. and the same at the front, where we only tested some of the 17-inch tires they use on the 500s just the once, and Colin was pretty unimpressed with them. 16.5 rubber is the way ahead." For the 2002 season Gorst expects the singleton factory SP-2 Superbike racer to build on the platform represented by the 'Ot. "The RC211 is Honda's revolutionary racebike." he says, "but here it's evolution, not revolution. But we have a good package, and it's fully sorted. We'll be right there in contention again next season. " cycle n e _ S • JANUARY 16,2002 17

• Cover