Cycle News - Archive Issues - 2000's

Colin Edwards' Castrol Honda RC45 h e passing of midnight on New Year's Eve 1999 announced - in motorcycling terms - the end of an era. For the first time in over two decades, the racing season will go on without a works Honda V-four in world-class fourstroke racing. Ever since the debut of the oval-piston NR500 at Silverstone in August 1979, Honda has made the V-four engine format its corporate engineering trademark. They've developed a range of street bikes around a mechanical architecture uniquely their own, as well as a succession of title-winning racers that in most cases have been derived from the models customers could buy in the showroom. The result has been a plethora of World- and National-level Championships won around the world over the past 20 years by Honda's signature V-fours _ from Mike Baldwin's 1982 AMA Formula One title aboard the meaty 1084cc FWS prototype, up to Doug Polen and Christian Laveille's ] 998 World Endurance crown on the RC45. In between, the distinctive, droning but dominant sound of the series of 90-degree Vfour Honda four-strokes in RS/RVF/ RC30/RC45 guise has reaped the Japanese giant a rich harvest of racing success, with innumerable victo- T 14 FEBRUARY 9. 2000' ries in the commercially crucial Suzuki 8 Hours matched by countless World Endurance titles thanks to a succession of wins in the European 24-hour marathons. And don't forget the six TT Formula One World Crowns (the final three courtesy of Carl Fogarty!) and three World Superbike Championships won by American riders - the first two with Fred Merkel aboard the RC30, the last thanks to RC45mounted John Kocinski. You might say the V-four format has proved its worth, having worked rather well for Honda over the years. Yet in spite of that, the V-four Honda four-stroke's day is now done, in sporting terms at least, with the imminent switch to the new RC51 one-liter V-twin, due to debut in the coming season. The RC45 is now a museum piece. Having track tested every single successive variant of Honda's V-four dynasty, from Freddie Spencer's early-'80s works VF750F Daytonawinning Superbike to the RC45 on which Aaron Slight came so close to finally clinching the World Superbike title in 1998, I've been privileged to acquire a unique appreciation from eye l e n e _ s the hot seat of Honda's technical mastery in developing their succession of V-four racers. Therefore, under the circumstances, the chance to ride the Castrol Honda RC45 that Colin Edwards took to second place in the 1999 World Superbike Championship before it retired for good to the Twin Ring complex's magnificent Collection Hall was more than usually memorable, especially as the unflagging efforts of the HRC engineering team led by Syuhei Nakamoto to end Honda's 20-year trip down the V-four Victory Lane with a final World Superbike title flourish had resulted in some significant improvements to the 6-year-old RC45 package for its final year of competition. These changes enabied the Texan to win five races against the cubed-up 996cc Ducati. If not for an injury sustained in pre-season testing that hampered him in the early races, Edwards and the Honda might have given defending champion Carl Fogarty's Ducati an even closer run - especially since, in typical Honda fashion, HRC engineers had kept working hard on V-four R&D right to the very end. These changes principally entailed the adoption of a radical and ingenious modification to the fuel-injected V-four engine, aimed at reducing power loss through inertia and oil drag by converting the wetsump motor to a "double-sump," or semi-dry-sump, format. Superbike homologation rules prevent the adoption of a separate oil tank as on the Aprilia RSV Mille, if the engine comes wet-sumped in stock form - so Honda did the next-best thing and fitted a 15mm distance plate between the crankcase casting lowers and the oil sump, which acts as a seperator to deliver the same benefits as a drysump engine in terms of keeping unnecessary oil drag away from the crankshaft. Coupled with twin oil pumps and the giveaway pair of clear plastic tubes on the right side of the engine to monitor oil levels on either side of the divider plate, this is actually not the first time Honda has pulled this trick out of their bag of technical goodies. The double-sump layout also facilitates the use of two-ring pistons, each with low-tension rings, all with the aim of reducing friction. This was first seen on Joey Dunlop's World TT Formula One title-winning RS750 V-four in 1984. Coupled with other mechanical improvements on

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