Honda Rc45
HONDA RC45
'94 PREVIEW
NEXT-GENERATION V-FOUR SUPERBIKE
SEVEN YEARS AFTER THE INTRODUCTION OF ITS GROUNDbreaking RC30, Honda has bowed to the inevitable. The once-dominant RC30, the production Superbike that caused other manufacturers to redouble their efforts in the late ’80s, is no longer. In its place is the long-awaited and highly rumored RC45.
“Although the kitted RC30, and now the RC45, are intended for racing, the street-going versions are meant to the finest expression of a street-going motorcycle Honda can make,” said a company spokesman. “For racing purposes, the RC45 could have been much cruder. The RC30 was a finely finished product that offered a sweet combination of handling and performance. The RC45 is intended to take over that role.”
The RC45, also known as the RVF750, was developed from the ground up as a joint Honda/HRC project. It is powered by a 90-degree V-Four with a 360-degree crankshaft, redesigned right-side gear cam drive and four valves per cylinder. Relocating the gear drive from the center of the engine eliminated one crankshaft journal and one camshaft journal, reducing engine size and weight. A narrow 26-degree included valve angle (down from 38 degrees) and shim-
under-bucket tappets further contribute to the engine’s compact, lightweight nature, as do three-ring, “slippertype” pistons and titanium connecting rods. Steeper, straighter intake ports lead to 2mm-larger intake valves, and composite cylinder sleeves (made from sintered aluminum impreg-
nated with ceramic and graphite) are used. Bore is up 2 millimeters to 72mm, but stroke remains unchanged at 46mm for a displacement of 749cc. Compression ratio is 11.5:1.
As expected, electronic fuel injection is standard issue on the RC45. Twin NACA-style slots pressurize the 7-liter airbox, which feeds a quartet of 46mm injector bodies, one per cylinder. Just as in the oval-piston NR750, sensors monitor barometric pressure, throttle position, coolant temperature, intake manifold pressure, intake air temperature, and crankshaft and camshaft position. According to Honda, alternative chips for the pre-programmed system will be available.
An all-new frame complements the uprated, fuel-injected engine. Large-section aluminum beams are paired with a cast steering head and cast swingarm pivot plates, and pressed and welded aluminum hangers hold the solidly mounted engine in place. Wheelbase is 55.4 inches, .1 inch shorter than the RC30. The single-sided Pro-Arm swingarm
remains, although it was redesigned to permit the use of a 6inch rear wheel and ultra-wide 190/55 rear tire. As before, a single nut holds the eight-spoke wheel in place, and the rear sprocket and brake are mounted directly to the arm, allowing for quick wheel changes.
Suspension is by Showa. The 41mm inverted cartridge fork has 4.7 inches of travel and features aluminum damper rods. It is adjustable for spring preload, and for compression and rebound damping. The CR-inspired rear shock absorber, with its integrated reservoir, is also fully adjustable and offers 5.1 inches of travel. Following the precedent set by the CBR900RR, the RC45 has a 16-inch front wheel. The benefit, Honda says, is less front wheel inertia and decreased unsprung weight. At a claimed 417 pounds dry, the RC45 will be light, but not overwhelmingly so. According to Honda, only 50 RC45s will be brought into the U.S., with the official release scheduled for March or April of next year.
Whether the RC45 will bounce Honda back to the top of Superbike racing, both in the U.S. and abroad, is yet to be seen. But if the prototypes raced in this year’s Suzuka 8-Hour are any indication, we’re in for a banner Superbike season. □
