Cycle News - Archive Issues - 2000's

(Left) Naked perfection. (Right) At the heart of the NSR is its V-four, two-stroke powerplant - now a museum piece thanks to the fourstroke regulations that go into effect this season. of what has turned out to be the 500cc category's longest-lived, and most successful, factory racer ever, the Honda NSR500. While the various MV Agusta, Yamaha and Suzuki works machines which might rival the V-four Honda's claim to long-term pre-eminence in fact all chopped and changed their engine designs over the years they were in contention, and the venerable Manx Norton single which outlasted it as a privateer bike enjoyed a mere half-decade as a full-on World Championship factory race tool, the Doctor's 2001 title-winning NSR500 has the same essential 54 x 54.5mm 112-degree V-four single-crankshaft crankcase reed-valve engine format as the first of the line which Freddie Spencer debuted back in 1984, before going on to win the first of the NSR family's 10 500cc world titles the following season. Only, much more powerful - yet arguably better behaved. So the fact that the next stop for the yellow and white number-46 NSR500 sponsored by Italy's Nastro Azzurro beer company and Spain's Repsol oil giant, after winning the final 500cc Grand Prix in road racing history in Brazil, was not the Honda Collection Hall museum at Motegi, but the Jerez race track in southern Spain, gave a handful of lucky journalists the chance to twist the wrist of the last of the Honda V -four twostroke line - and, in so doing, to commemorate another milestone in the motorcycle race annals. For after failing in the year 2000 to win a single World Rider's title in any GP class for the first time since 1986, and losing their coveted World 500cc Manufacturers crown to Yamaha, and surrendering the riders' championship to Suzuki, Honda was thirsting for revenge. Troubled defending World Champion Alex Criville had won only a single race in 2000, en route to a dismal ninth place in the final World Championship points table - better than managed by his Repsol Honda teammates Tadayuki Okada and Sete Gibernau, though, who were still more shipwrecked by controversial changes in the NSR500's specification, and didn't even manage to break into the top ten of the world title standings by the end of the season. How come? Well, as HRC engineers explained when I tested CrivilIe's title-winning NSR500 in Japan back in 1999, with the Yamaha frequently faster and the Suzuki usually better handling they reckoned the time had come to redesign a motorcycle that had remained essentially unchanged for most of the past decade. So Honda engineers had decided to go for more top-end power to counter Yamaha's new straight-line supremacy and the YZR500's superior jump out of a turn, as well as a revised chassis to handle it. This meant that the works Repsol Honda team riders turned up for the first few races in 2000 with a bike whose fierce power delivery and vicious engine acceleration gave them big problems in terms of traction - actually getting the extra power to the ground was impossible, and tire life was greatly reduced, because of wheelspin. Midrange power was actually reduced, making it hard for the riders to feel the fabled connection between the throttle and the rear tire - but when the extra horsepower did arrive, it did so in an explosive way that unhooked the back end of the bike: fine on a dyno, not so on the race track, a fact openly confirmed to me by HRC president Yasuo Ikenoya a year ago. "We made a mistake in 500GP R5D at the start of this season," he confessed, "and only now have we begun to catch up in new-model testing for 2001. The problem has been for our riders to get traction coming out of a tum, and also aerodynamics - we must study very carefully the airflow into the engine, as well as the profile of the complete motorcycle. But now we found the correct direction, and will challenge again for success next season." Guess the way things turned out proved his optimism was justified. Trying to resolve these shortcomings in the short term via chassis modifications and suspension settings proved impossible, so the works team reversed out of the dead end they'd just gone down and went back to the old '99 engine and chassis package. This was an only partly successful effort to make up for lost ground, in a season in which all three Japanese well as airflow being a new chassis plausibly similar to the one used on Honda's World Superbike title-winning SP-1 V -twin. This locates the engine further back in the wheelbase, responding to Rossi's complaints about excessive wheels pin on the old machine, by improving traction and thus countering Yamaha's edge on acceleration - while a raised but still adjustable swingarm pivot and a new hunchback swingarm design also combine to help enhance grip. Moving the engine rearward dictated new crankcases for the V-four motor, since the swingarm pivot would otherwise foul the gearbox sprocket, at which around 195 hp is produced at 12,500 rpm - about 7 hp up on last season's bike - while to achieve Valentino's preferred riding position with lots of body weight transferred onto the front wheel via the handlebars, allowing him to push harder in turns, there's a new subframe that raises the height of the seat quite substantially compared to before. manufacturers were now level-pegging - but then as Honda's new signing, reigning World 250cc Champion Rossi, started to get the hang of racing a 500, it was he that swiftly became the Honda standard-bearer, first to receive the updated parts that HRC engineers were hard at work developing, to counter the problems more senior Honda riders had experienced at the start of the year. With Mick Doohan's old team of mechanics running Rossi's bike, headed by the architect of his five world crowns, race engineer Jeremy Burgess, the fact that the singleton machine ran in Nastro Azzurra colors rather than the Repsol livery of the works team, underlined the ad hoc arrangement of the whole operation - a fact which doubtless caused no little angst on the part of Honda's big-money Spanish sponsors. So for 2001 and the last year of factory 500cc two-stroke racing, Honda made sure they got it right. Starting the day after the final GP of the 2000 season in Australia, Rossi began test riding a heavily revised NSR500 with different engine characteristics aimed at meeting his needs, with which he went on to win the first three races of 2001, to set up an irresistible charge on the world title that was eventually to become his. With different cylinder porting and especially the longer, slimmer expansion chamber exhausts which are the only outward sign of the internal modifications aimed at improving rideability (cylinder heads, porting, ignition and exhaust valve curves, mainly) and the four 36mm dual-body Keihin carbs with electronic sensors monitoring the throttle position, exhaust valve operation and engine rpm, breathing cleaner, cooler air via an all-new intake system with a central letterbox airduct in the nose of the bike leading to the redesigned airbox, rather than the side ducts of the existing bike, the new Honda looks different as well as performing better - a fact which especially Loris Reggiani, forced to ride the older, bulkier, less aerodynamic twin-intake lease NSR500 for Team Pons, bitterly resented. Engine performance and aerodynamics aren't the only variations between old and new, though, with the most obvious external change besides the horizontal radiator located low down to improve cooling as cycle BE LIKE VALENTINO You notice this at once as you climb aboard the Nastro Azzurro bike in what remains of pit lane at Jerez, after picking your way through the building site which is all that's left over from the old garages. Compared to the Criville NSR500s, or Mick Doohan's bikes for most of the rest of the '90s, you sit quite a bit higher on, rather than in, the Rossi bike, which also seems more spacious - perhaps reflecting the lanky Italian's long limbs. But it also seems notably slimmer and less bulky than a.ny of the 16 other years of Honda's NSR500 vintage I've ridden since my first such test of Freddie Spencer's title-winning bike back in 1985, and this is reflected in the way it steers. For starters, the Rossifumi racer not only stopped much better than Colin Edwards' SP-2 V-twin Superbike I'd been riding earlier - a fact you'd expect thanks to the GP bike's 70 pounds lighter weight and ultraeffective 320mm Mitsubishi carbon discs gripped by four-piston radialmounted Brembo calipers - but it also felt much more balanced stopping hard, and steered into turns more controllably, while still trail-braking into the apex. Where the Edwards bike lifted the back wheel under braking and moved around almost as badly as Kenny n e _ S • JANUARY 9.2002 15

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