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/127607
URIDING IMPRESSION ~K 0\ 0\ 1994HondaRC45 b.ut tke ~t 'l""""I The all-new Honda RC45 uses a single-sided swingarm (right) and four-piston Nissin front brakes (bottom right). The RC45 will be ridden by Doug Polen and Aaron Slight in the 1994 World Superbike Series. By Paul Carruthers Photos by Donn Maeda ond a built the Honda RC45 for four reasons: 1) The World Superbike Championship; 2) The AMA National Superbike Championship; 3) The All-Japan Superbike Championship; 4) The Suzuka 8-Hour. Th ey've built the best motorcycle, they've hired the best riders, and they don't plan on finishing anywhere other than first. Sister-kissing is not what the Honda RC45 is all about. With the All-Japan Championship converting from Formula One to Superbike rules in 1994 - and the Suzuka 8Hour following suit - it was imperative that Honda build a streetbike-based motorcycle with performance close to the one-off Honda RVF750s used previously in that championship. The RC45 is just that, a streetbike-based motorcycle. Trust me on this one: Honda didn't have you and me in mind when they sat down at the drawing board and started designing the RC45 - this bike is built for the Doug Polens, the Aaron Slights and the Kevin Magees of the world. That's okay. At $27,000 you and I can't afford one anyway, but at least I was given the opportunity to ride an RC45 even before new Honda-signee Polen got his grubby little hands on one. Honda chose its elaborate, $35 million Honda Proving Center of California testing facility to introduce the RC45 to members of the American motorcycling press. We were given an opportunity to briefly ride the two RC45s on the Proving Center's new road course and also on the 7.S-mile oval that circles the facility. Strict instructions of "crash one and we'll have to kill you" kept riding impressions short and sweet, but you only have to look at the RC45 to know what it's capable of. H 46 Trick, trick, trick... A t the heart of the RC45 lies the 749cc liquid-cooled, 90-degree V-four. Honda didn't just tweak a little bit on the seven-year-old RC30 powerplant they reinvented it. The new-generation V-four is straight out of HRC, developed by project leaders with engine and chassis backgrounds straight from Honda's long list of trickery - the NR500, the NS500, the NSR250 and NSRSOO, and the NR7SO. The goal was to build a lighter, more compact V-four with a power output of ISO horsepower in race-kitted form. Using things such as metal composite (sintered aluminum powder mixed with ceramic and graphite) cylinder sleeves, weighing 3.3 pounds less than the steel sleeves used on the RC30 engine and also providing better heat d issipation, and a lightweight magnesium head and sprocket covers, HRC ended up with an engine some nine pounds lighter than the RC30 powerplant. The air box was beefed up from 3.4 to 7.0 liters. Straighter, steeper downdraft intake ports, a closer 26-degree included valve angle, a 2mm larger bore (72mm) and fully transistorized ignition all combine to give the necessary power output. The RC45 also uses three-ring "slipper" pistons and titanium connecting rods. , Also new is the gear-driven valve train which is positioned on the right side of the engine to allow for closer cylinder spacing and thus more compactness. The train directly drives each set of camshafts with spring-loaded split gears, claimed to reduce noise, and elminates one crankshaft journal and one camshaft journal for even more weight loss. Honda personnal are frank when they discuss the key to being competitive in the superbike wars - fuel injec- tion. Based on the Programmed Fuel Injection (PGM-FI) system developed for Honda's NR750, the new system uses the same set of seven sensors to monitor key points of operation, and a dedicated central processing unit to accurately control performance. The system's four injector throttle bodies feature large, 46mm bores for optimal airflow around the large butterfly valves. The pre-programmed system will feature programming adjustability on the race version (via six knobs) , but not on the street version. Instead of the RC30's 125mm, 10plate clutch system, the RC45 uses a 14Omm, eight-plate clutch taken directly from the NSR line. The clutch works in conjunction with the close-ratio, sixspeed transmission which features undercut shift dogs to prevent missed shifts. To help cool the RC45 powerplant, Honda has added a pair of fan-assisted aluminum radiators, and an air-cooled oil cooler that's positioned to the side of the radiators. The four-into-two-intoone exhaust system on the RC45 uses an impact-extruded aluminum silencer similar to those found on the CBR900 andCB1000. The lightweight and rigid triple-box, twin-spar frame comes straight from the RVF - not a replica, the real thing. The suspension goes right " along with the rest of the motorcycle - the best. Up front, the Honda gets a fully-adjustable (12-click compression and rebound adjustments as well as pre-load adjustability) 41mm inverted fork that uses aluminum cartridge rods and cylinders - a first for a Honda street-going motorcycle. The outer stanchion tubes are goldplated and sit in cast aluminum upper and forged aluminum lower triple clamps; the steering head stem is also made of alumile-plated aluminum. The rear suspension is a gas-charged Honda Pro-Link system (providing 5.1-inches of travel) that's based on the CR motocross line. The key to the rear end, though, is the cast-aluminum, one-sided Pro-Arm swingarm, designed for strength and quick wheel changes. The RC45 streetbike comes with a 3.50-16-inch front wheel, rather than the 17-inch wheel found on the RC30. This allows for a 130/70-16 Dunlop Sportmax radial which, Honda says, gives the same effective diameter as the 120/70-17 used on the RC30. According to Honda personnel, the race version RC45s will use a 17-inch front wheel - because of the wider variety of 17-inch slicks avail-' able. The rear wheel features a 6.00-17 rim that will be mounted with a 190/SO Sportmax radial. The front brakes use the same Nissin four-piston calipers used on the CBR900 and the same 310mm rotors used on the NR. The rear brake uses a twin-piston caliper system on a 220mm rotor. The RC45's appealing looks are highlighted by the full, white and red fairing