Forbidden Fruit

FORBIDDEN FRUIT

THE QUICKEST WAY THROUGH A SET OF CORNERS? FORGET l000s. A 400 IS WHAT YOU NEED.

HERE'S A GIVEN: FEW PRODUCTION VEHICLES, two-wheeled or four, can approach the brutal acceleration of an Open-class sportbike. Here's another, trust us on this: When it comes to attacking a really gnarly set of twisties, something with more kinks than a San Francisco leather bar, nothing—n-o-t-h-i-n-g—will beat a 400cc repli-racer.

On a recent visit to Japan, Cycle World reacquainted itself with this dictum aboard two Honda featherweights, the RVF400 and the CBR400RR, as we sifted through Tokyo traffic and tackled the beautiful, serpentine roads in the heavily wooded mountains southwest of the city.

Short of engine size and winged Honda decals, this pair seems to share few similarities. The RVF400 V-Four could easily be mistaken for its larger sibling, the RC45, while the CBR400RR inline-Four has a look all its own, one that’s quite removed from that of the CBR900RR. Mechanically, however, we find several parallels.

Both bikes displace 399cc, with identical 55.0 x 42.0mm bore-and-stroke dimensions. The RVF’s compression ratio is 11.3:1 while the CBR comes in a bit higher at 11.7:1. Both have four valves per cylinder, with gear-driven dualoverhead cams. The RVF’s cam lobes act upon rocker arms while the CBR has a shim-under-bucket design.

Each has a large-volume airbox under the fuel tank feeding a bank of four 30mm Keihin mixers. Each is fitted with a throttle-position sensor for intelligent mapping of the ignition-timing curve and both use 4-2-1 exhaust systems. Power is routed through cable-actuated, multi-plate wet clutches and closeratio six-speed gearboxes. Both are rated at 53 horsepower, the RVF's curve topping out at 1 1,500 rpm while the CBR peaks at 12,000 rpm before tapering off. Instrumentation, identical on both, is similar in design to that of the CBR900RR. While their tachometers indicate 14,500-rpm relines, each will twist the needle beyond the 15,000 mark before a rev limiter cuts in.

Differences become readily apparent in the two chassis. The RVF’s twin-spar aluminum frame employs a cast steering head and swingarm-pivot plates, linked by stout, extruded main beams. A cast-aluminum, single-sided Pro-Link swingarm, like that of the RC45 or VFR75 carries a 4.5 x 17-incl wheel with 3 t s v 17 at the front, same as on the CBR400RR. Adjustable rebound damping and spring preload are provided on the Showa inverted cartridge fork and single rear shock. Weighing a claimed 403 pounds without fuel, the RVF stretches over a 52.5-inch wheelbase; 25.0 degrees of rake and 3.6 inches of trail complete the little V-Four’s steeringgeometry statistics.

The CBR400RR's unique-looking frame is also a mix of castand extruded-aluminum pieces. Its large, semi-omegashaped cast swingarm-pivot plates are tied together via a cross brace above the gearbox. The brace serves as the top mount for the rear shock in a layout similar to that of the CBR600F3. The two-sided swingarm is an aluminum casting, its right leg a gull-wing design that allows the exhaust to be tucked up and in for improved cornering clearance on that side. A conventional cartridge fork is used with the same array of suspension adjusters as on the RVF.

The CBR weighs a claimed 397 pounds without gas, has a 53.7-inch wheelbase, 24.5 degrees of rake and 3.6 inches of trail. Like the VFR, steering is light, neutral and ultra responsive. Perhaps even more impressive is the high level of chassis stability these bikes display at high speeds. Unflappable is the word.

The CBR's frame design makes for a very narrow midsection between the rider's knees. Both bikes place their rider into a semiaggressive posture with a moderate reach to clip-on handlebars. Each has a fairly firm and thin seat pad, allowing free side-to-side movement of the rider, ideal for sporting duty but taxing on the freeway. At freeway speeds, engine-vibration levels are minute, the RVF giving off that characteristic V-Four grumble in both exhaust pitch and feel through the pegs and bars. Even at sewing-machine revs, both bikes buzz relatively little.

Aside from the RVF suffering a slight carburetion stumble just off idle, both bikes also have surprisingly broad spreads of usable power. Much of our time was spent with the engines spinning between 6000 and 1 1,000 rpm. On each, power delivery is quite linear without a pronounced hit anywhere in the rev range, though slingshot drives out of corners require revs to remain above 9000 rpm. Clutch and shifting action is light and smooth, a sweet bonus when rowing up and down through the gears on a windy stretch of road. One welcome side benefit of light weight is braking of running-into-boiler-plate proportions. The RVF a pair of four-piston Nissin calipers while the BR makes do with a twin-piston pin-slide design. Both bikes use identically drilled, stainless-steel, floating rotors and a CBR900RRstyle, remote-reservoir master cylinder. With the shortness of wheelbase on these two, lofting the rear tire under heavy front-brake use is a common occurrence. Stoppies-R-Us! Now for the bad news. Unless you live in Japan or somehow snag a staff position here at Team Cycle World, Honda’s fab 400s are as off-limits as crack cocaine at Betty Ford’s. With the RVF400 selling for roughly $7800 in Japan and the CBR400RR getting $7400, they just don’t make sense. Unless you’ve ridden one.

Don Canet