Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126770
freddie Spencer's .SR5DD Handa By Peter Neilsen Continuing in the tradition of the NS500 triple, Honda's new works wonderbike the NSR500 ridden by Freddie Spencer was a winner almost right out of the crate. 20 Even though the 499cc NSR500 developed an exhaust I k d . ea. unng the Daytona 200 whIle Spencerraced for the lead with the 695cc OW69 Yamahas of Kenny Roberts and Eddie Lawson, a.nd even though the bike's carbonfiber rear wheel broke at the South Africao GP(sendingSpencer imo the haybales), the NSR500's victory in Italy has signalled its potency. Honda released the cutaway drawing seen here to the press at the Italian Grand Prix. It is a water-cooled two-stroke V-4, bore and stroke 54x54.5mm, the cylinders angled 90° apart, each sharing a common crankshaft. A bank of four carbs sits behind the rear cylinders and feeds four separate crankcases through reed valves. Each exhaust port is fitted with Honda's ATAC power chamber system, and the exhaust systems curve back, over the top of the engine and underneath the seat. The8.5-gallon aluminum gas tank is slung beneath the engine, ELF e style, and the fuel is pumped up to a holding tank behind the steering head. From there, gravity feeds the carbs. A gear-driven countershaft beneath the crankshaft drives the six-speed -transmission through a dry clutch located on the right side of the engine. The final drive sprocket is on the left side of the engine. The engine i remarkably compact but it's still squeezed in tightly between the massive built-up alum~ inurn-alloy frame members. The heavily-braced aluminum alloy swingarm pivots just behind the countershaft sprocket, and it's connected to the upright rear shock through a Pro Link linkage system. The remote reservoir for the shock is positioned in front of the rear wheel. The exhaust expansion chambers are overed by a two-piece shroud with asbestos insulation facing the pipes and an air space between the bottom and top pieces. Cooling air is ducted from two fairing scoops, through the shroud, exiting underneath the seat. Despite all that, the top shroud overheated and made Spencer very uncomfortable at Daytona, when the bike developed an exhaust pipe leak. Reaching the spark plugs requires considerable dexterity from mechanic GeorgeVukmonovich, who maintains the NSR500 under the direction of Erv Kanemoto. Things are further complicated by the maze of water and fuel lines around the engine. The front forks are made of carbonfiber; front brakes are fully-floating stainless steel discs, with four-piston magnesium calipers. The front wheel isa 16-inch, mounted witha Michelin radial tire. The rear wheel is a 17-inch, again with a Michelin radial, and the rear disc is carbon fiber. Both front andrear wheels are Honda ComStars; they're probably not made of carbon fiber since a carbon-fiber rear wheel broke and threw Spencer down the road at South Africa. According to Honda, the NSR500's wheelbase is 54 inches; overall height is 44 inches; overall width 22 inches; overall length 77.9 inches. Claimed horsepower is over 138 bhp. •