Honda Readies R1-Beater

HONDA READIES R1-BEATER

ROUNDUP

WITH THE 1993 INTROduction of the CBR900RR, Honda initiated a new motorcycle category: the "power-to-weight" Open-classer, which combines the agility and lightness of a 600cc machine with the acceleration of a 900/1000cc motor.

It was a popular concept, and over the years, Honda sought successfully to widen the circle of consumers to whom the bike appealed. In one major redesign, chassis stiffness was relaxed to soften road feedback for average riders. In a second, newly learned lessons in exactly how and where a chassis should or should not flex were applied, resulting in even higher performance and still wider appeal. Now, rumors suggest that Honda may have changed its “wider-circle” engineering policy. How about a CBR1000RR with hot NSR500 styling, an inverted fork, six-piston brake calipers and close to 165 horsepower? This is the prediction made by Japan’s often-spot-on Young Machine magazine for the 2000 model year.

Why would Honda reject its wider-circle policy in favor of a tighter sportbike focus? Yamaha’s successful YZF-R1, that’s why. While delivering edge-ofthe-envelope performance, the R1 is civilized, tourable even. It is the definition of an extremeyet-civilized motorcycle. Isn’t that what the RR was supposed to be? Such a challenge can’t be ignored.

Okay, from where does the horsepower come? The current CBR makes maybe 125 crankshaft bhp. How do we get to 165 from a postulated 998cc? Thoughtful people noticed that the original 900’s bore and stroke were exactly what you’d expect if a not-produced CBR750 were stroked, not bored, to 900cc. The result was a longish stroke and a bore/ stroke ratio far from Honda’s usual sportbike number of 1.5:1. The high piston speed that results from that longish stroke limits the current 900 to less-than-stellar revs. What if the engine were redesigned from the ground up, with Honda’s usual bore/stroke ratio? We would get new numbers like 75.0 x 50.5mm. This stroke is sufficiently shorter than the old 900’s to safely and reliably allow revs at peak power to rise by about 13 percent. Multiply in the 10 percent boost in displacement, and throw in the latest refinements to porting, valve timing and combustion, and what do you get? Why, 165 crankshaft bhp at 12,000 rpm.

There’s no need for this notional Super Fireblade to be a great departure from the widercircle policy. Yes, 165 is a big number, but fuel injection and pointy cam lobes effectively civilize high horsepower. Nothing in the rest of the CBR1000RR package-styling, fork, six-piston stoppers-makes any waves on Honda’s wider circle. Modern chassis and suspension can handle this power without a lumberwagon ride. The circle may grow wider yet.

-Kevin Cameron