Honda Rc45
HONDA RC45
CYCLE WORLD TEST
V-FOUR, THE NEXT GENERATION
LAST SPRING, THE FÉEDÉRATION INTERNATIONALE Motorcycliste announced that motorcycles raced in 1994 World Endurance Championship events, including Japan's prestigious Suzuka 8Hour, would have to be production-based. Even at the manufacturer level, the FIM decided, one-off prototypes and factory specials had become too expensive to justify.
Knowledge of the impending rule change put Honda in a difficult position. Its twice-world-chain..
pion RC3O was no longer competitive, even with extensive updates. Worse yet, the exotic RVF75O racer was deemed too expensive to reproduce in the required homologation numbers. Clearly, somethj~g had to be done.
The result is the much-rumored RC45~1
"Honda's goal was to develop the best Superbike in the world," said a company spokesperson at the bike's U.S. introduction. "The RC45 is the platform from which Honda will base its domestic and international Superbike efforts."
T,~_1 ?Ln~t~j1JtJjL~. Well, anticipation, hype and introduction hoopla aside, Cycle World's initial impression of the production RC45 was disappointing. While the bike handled well enough, its engine performed poorly, backfiring on trailing throttle and losing power 2000 rpm before redline. Rear-wheel dynamometer tests confirmed the impression: 86 horsepower at 10,500 rpm. In comparison, Honda’s street-oriented 1994 VFR750F produces 94 horsepower, and if that’s not damning enough, our ’93 Kawasaki ZX-6 made 88 horsepower.
The problem was traced to a faulty electronic control unit (ECU). Apparently, the circuits that control an EPA-pleasing air-intake-duct control valve atop the airbox were sending the wrong messages. Also, the valve’s return spring was too weak, allowing the valve to close at higher rpm, cutting off the air intake.
Production models will be fitted with updated ECUs, which will have both European (118 claimed horsepower) and U.S. (101 claimed horsepower) data. “It will be possible-for racing purposes only-to modify the ECU to obtain full performance,” hinted a Honda spokesman. The operation apparently involves the simple cutting and splicing of wires to access the high-power Euro settings.
To override the problem temporarily, Honda plugged the control valve’s vacuum hose, forcing the valve open. So modified, the engine peaked at 97 horsepower, again at 10,500 rpm. An improvement, but still disappointing. We obtained all performance data in this modified form. At the conclusion
of the test, just as we were going to
press, Honda shipped us a European ECU, which was installed in time for another run on the dyno. This time, the supposedly uncorked RC cranked out 102 horsepower.
For those after more power-certainly for racers who plan on going after Superbike wins-hop-up parts will be available. The Basic Superbike Kit and Optional Racing Kit are very extensive and can be ordered through American Honda’s racing department. Prices for the kits, which will include an exhaust system, bodywork with ram-air intake funnels, sprockets, programmable fuel injection, suspension pieces and wheels, have not been determined. HRC prepped, race-only engines, guaranteed to produce 148 horsepower, will sell for approximately $20,000 each.
While the old RC3O's powerplant was based on the RVF750 endurance racer, the RC45's 90-degree V-Four is an all-new design. Displacement is 749cc, and pre-set elec tronic fuel injection sourced from the oval-pistoned NR750 monitors barometric pressure, throttle position, coolant tern perature, intake manifold pressure, intake air temperature, and crankshaft and camshaft position.
For compactness and reduced weight, the NR7~tJ-inspirea am-gear drive was moved to the right side of the engine,
eliminating one camshaft journal and one crankshaft journal. A narrower, 26-degree included-valve angle, steeper intake ports, a shorter, 46mm stroke (RC30 stroke was 48.6mm) and a beveled front cylinder-head cover furthered the cause, as did a more deeply set oil filter. This compactness allows the engine to be located farther forward in the chassis, more so than with the RC30, for additional front-end weight bias.
This redone V-Four makes power in a smooth, linear fashion. The fuel-injection delivers quick starts, and once up to operating temperature—indicated by a liquid-crystal watertemperature gauge-the engine revs freely and emits a wonderfully visceral exhaust note. Throttle response is immediate, almost irritatingly so, especially when combined with the bike’s considerable driveline lash.
On really tight canyon roads, there’s little reason to shift out of the RC’s tall first gear, which is good for an indicated 80 mph. Ratios are closely spaced, but upshifts aren’t terribly smooth or precise. Downshifts presented no problems. The eight-plate clutch (borrowed from the NR750) is beefier than that of the RC30, but the tall first gear still makes for difficult dragstrip launches; after eight moderately hard launches-best was 11.71 seconds at 121.95 mph-our testbike’s clutch was finished. Outright top speed, hampered by
U.S. ECU settings, was an uninspiring 147 mph.
In street trim, the RC45 is very civilized. Closer inspection, however, reveals a more narrow focus. The frame is aluminum, with massive, triple-box side beams welded to a cast steering head and swingarm-pivot plates. According to ITonda, torsional rigidity was increased substantially over the RC30’s design. Pressed and welded hangers hold the engine in place. The detachable subframe also is aluminum.
Showa suspension components are used at both ends. The fully adjustable 41mm fork features aluminum cartridge rods and cylinders, a first for a street-going Honda. Machine-tapered stanchion tubes are secured by a cast-aluminum upper and forged-aluminum lower triple-clamps, connected to an aluminum steering stem.
The RC45’s single-sided, Pro-Arm swingarm has been redesigned to permit a wide, 190/50 radial rear tire, and offers 5.1 inches of travel through a fully adjustable, piggyback-style shock absorber. Why not use a remote-reservoir type? According to Honda, the shock incorporates a heatcompensating device (seen last year on kitted RC30s) that alters damping rates as oil temperature increases. In theory, then, suspension action would remain consistent duiing even the most demanding racing conditions.
The bike feels very small, and handling is lighter than that of the CBR600. Steering is very neutral, with little pressure
required to keep the bike on line. Mid-corner line changes require minimal effort. Considering its mission, the suspension is very compliant. With rebound damping set three clicks in from full-soft, for example, the fork worked well in both canyon and freeway environments. Spring and damping rates at both ends are firm enough to maintain exceptional chassis control during hard riding, but the suspension remains compliant over bumps and ripples.
Like the CBR900RR, the RC45 is fitted with an unconventional 16-inch front wheel. The claimed benefits are less rotational inertia and decreased unsprung weight. In addition, says Honda, the wide production tolerances of DOTapproved 17-inch tires can create engine-clearance problems on full fork compression. Racers can fit 17-inch wheels because “slicks have a tighter tolerance, there are fewer of them, and they don’t present any clearance problems.”
Front brakes are 12.2-inch, floating NR750 rotors with Nissan four-piston calipers sourced from the CBR900RR. No complaints here. Testers liked the progressive power and firm lever feel. At the rear, a single, 8.7-inch disc and twinpiston caliper are fitted and work favorably, as well.
Even though it is intended for racetrack use, the RC45 is relatively comfortable, with a short reach to the bars and moderately high footpegs. The wide foam seatpad is plenty thick, with ample room to change position. Taller riders will have a difficult time crouching below the flat windscreen, although the recessed fuel tank helps somewhat. The minimalist switches are CBR900RR parts, the adjustable clutch and brake levers sourced from the VFR750F.
Considering its staggering $27,000 price tag, the RC45 is a letdown in terms of outright acceleration and top speed. But as Honda has emphatically stated, the bike is intended as a basis for Superbike racing; the street-going version is merely an expensive formality in the homologation process. So, with the right parts, knowledgeable mechanics, and riders like World and AMA Superbike Champion Doug Polen and former grand prix star Kevin Magee at the controls, the RC45 may live up to its expectations. As an exotic streetbike, though, it doesn’t. ®
HONDA RC45
$27,000
EDITORS' NOTES
EVER BEEN ALL WORKED UP, HAVING received a great new toy, only to be let down when you get it out of the box and discover that some assembly is required? In a sense, the Honda RC45 was like that when it first rolled out of the Cycle World box van. Initially, engine performance was a disappointment, but after a quick-fix of the airbox-intake valve and an ECU
airbox-intake valve and an ECU swap, the RC became a serious road tool. Its spread of power is so broad and seamless, the close-ratio, racing gearbox hardly seems appropriate on the street. Fun to shift, though.
Few bikes I have ridden on the street handle as sharply as the RC45, and fewer yet make as much use of first gear. On one of my favorite roads, a tight series of curves up a mountain, I never once got into second.
For my money, I’d be much happier owning the new VFR750, unless 1 was going after an AMA Superbike title that is. Then the choice becomes obvious.
-Don Canet, Road Test Editor
FOR ME, THE RC45 is MERELY A PIPE dream, much like the oval~piston NR750 or Bimota's stunning new SB6. I don't have enough greenbacks to plunk down on any one them, and even if I did, I would probably put it towards something with four walls and a roof. r~F; umpressed with Honda's effort. On the contrary, the RC45 is V-Four nirvana on wheels,
even in its restricted forim TrUe, the performance numbers are disappointing, but the engine's linear power delivery and stirring exhaust note almost make up for them. And the chassis, while not intended for freeway travel, is rock solid at hair-raising lean angles.
If you’re on a budget, Honda makes another V-Four-powered sportbike that, in stock form, is faster, more comfortable and less than one-third the price. Even so, if one of California’s finer lending institutions could find a way, I might just be tempted to order one of these beauties-with the Euro ECU, of course. —Matthew Miles, Managing Editor
WHAT'S WRONG WITH THIS PICTURE? Flonda, the world's number-one motor cycle-maker, unveils its flagship 750cc sportbike, one of the most eagerly anticipated models of recent times, subject of spyshots and preview after preview worldwide, and then it gets sawed by a run-of-the-mill Kawasaki 600, even after last-minute jury-rigging to deactivate some faulty flapper valve? Then, we're told with a wink anda nudge that `n ers can diddle with the electronics to liberate another 5 horsepower, but only if they're going cIosed~course racing, if you know what we mean.
For this, and with nary a strand of carbon-fiber in sight, Honda has the nerve to ask almost $30,000?
I’m a big fan of V-Fours and 1 love exotica, but sorry, I’m not buying. If I wanted a Honda 750, it’d be the excellent VFR750. With the almost $20,000 I’d save, I could buy something really exotic-say a Ducati 916.
-David Edwards, Editor-in-Chief
