Supersport Shootout
SUPERSPORT SHOOTOUT
CW COMPARISON TEST
LOCKED AND LOADED: HONDA CBR600F3 vs. KAWASAKI ZX-6R vs. YAMAHA YZF600R
IN RECENT SOLO TESTS OF THE HONDA CBR600F3 AND the Kawasaki ZX-6R, each bike, in turn, took the world by storm. First, the F3 set marks for quarter-mile acceleration that 750s of a few years ago would be proud of. Then, it was the all-new ZX-6R flying the middleweight colors deepest into 750cc territory, with a dragstrip showing of 10.89 seconds at 128 mph, backed by a top speed run of 154 mph. In the battle for 600-class supremacy, we were witnessing a veritable performance blitzkrieg.
And just where does Yamaha’s YZF600R fit into the picture? A class veteran due to its mid-’94 release, it wears the 1994 AMA Supersport Champion’s medal, but faced with the enemies’ upgraded equipment, seemed outflanked on both fronts.
It was time for a straight-up confrontation.
We re-upped the three Top Guns of the 600 class for head-to-head combat at the following venues: Carlsbad Raceway’s dragstrip; our desert-road high-speed site; the Willow Springs road course; and our Dynojet rear-wheel dynomometer. Before we get on with battle-damage assessment, though, lets have a tech briefing comparing our three middleweight combatants.
Each is powered by a liquid-cooled, 16-valve, inline-Four displacing 599cc. All use compact, shim-under-bucket dohc valvetrains. The YZF’s cam chain is located on engine centerline; the F3 and 6R cams are driven off the right end of the crank. The 6R’s bore and stroke is the most oversquare, the large bore allowing for larger-diameter valves while the short stroke lowers piston speed for a class-high redline of 14,000
rpm. The F3 comes close, spinning to 13,500 rpm, with the YZF redlined at 13,000. The Honda and the Yamaha both have 12.0:1 compression ratios; the Kawasaki a tick less at 11.8:1. All three channel their power through cable-actuated multi-plate wet clutches and six-speed gearboxes.
Removal of the steel fuel tank on any of the three reveals a large-volume airbox feeding a bank of Keihin downdraft carburetors (34mm on the YZF, 36mm on the F3 and 6R). While both the Kawasaki and Honda boast ram-air induction, Yamaha employs a simple snorkle inlet placed under the tank. All three bike-makers agree on 4-into-2-into-1 exhaust systems for a good balance of midrange and top-end power, and each mill is hung in a perimeter-style beam frame.
Further parity is found in chassis geometry, with less than 1 degree difference in rake, a quarter-inch difference in trail and one-tenth of an inch difference in wheelbase between the three. Without fuel, the ZX-6R weighs-in 11 pounds under the YZF and 6 pounds under the F3. The 6R’s frame and box-sec-
tion swingarm are both made of aluminum. The YZF’s Deltabox frame and swingarm are steel, as are the Honda’s. Each bike has wheels measuring 3.50 x 17 front and 5.00 x 17 rear, carrying identically sized Bridgestone Battlax tires.
Putting the check on speed for each bike is a pair of drilled stainless-steel floating rotors up front and a smaller-diameter fixed rotor at the rear. The Kawasaki and Yamaha use four-piston calipers up front, while the Honda gets comparable results from a
two-piston, pin-slide design.
After a week of standing on ready alert while the worst rain storms in a decade lashed California, a break in the weather allowed operations to commence at Carlsbad Raceway. As predicted, the YZF took the biggest hit in this initial phase, posting a best run of 11.72 seconds at 117 mph, a bit slower in both time and speed than last year’s testbike. The YZF’s grabby clutch and light flywheel weight conspired to make getting a clean, hard launch a difficult task.
Next came the F3, a bike that had advanced to within a trench row of breaking into the 10s when tested here a few months earlier. The F3’s best pass of the day, 11.21 seconds at 122 mph, was well short of its previous mark of 11.05 at 125 mph. Since grip off the line wasn’t a problem, the loss of mph would indicate atmospheric conditions were less than ideal.
Last to enter the fray was the ZX-6R, the only stock 600 CW has ever run into the 10s. Suffering from anemic carburetion that caused a pronounced stumble on each upshift and surging on top end, the mighty Ninja, a different unit than we previously tested, seemed to have lost its fighting spirit. With a best effort of 11.37 seconds at 122 mph, it had retreated a half-second and 6 mph-significant enough to cast a cloud of uncertainty upon the validity of its recent triumphs. Might the Honda also have run in the 10s if tested on the same day the 6R made history? Such is the fog of war, underscoring the whole puipose of conducti ing a multi-bike shootout. We M withdrew from Carlsbad, scratching f our heads in amazement at how much the battle lines had shifted.
High-speed testing at our classified site in the Mojave Desert proved that all three 600s were bedrock-steady at top speed. East and west runs on the YZF averaged out to 141 mph, 2 mph slower than last year. On the upswing, the F3’s 147-mph average was 2 mph above the posting in its recent solo test. Retaining honors as undisputed class speed demon was the ZX-6R, wñth a 150-mph average. Still, that’s 4 mph down on the mark our first 6R testbike had established, once again indicating the Kawasaki’s carb glitches were holding it back.
Phase Three of our battle plan saw CW tester and 1993 World Endurance Champion Doug Toland joining Road Test Editor Don Canet as the action shift ed to the newly widened and resurfaced Willow Springs Raceway. While the standard-equipment Bridgestone tires fitted on each bike offer superb performance for aggressive road riding, maximum grip with this street-compound tire would have been short-lived on Willow's ultra-fast, 2.5-mile roadcourse. Dunlop's new Sportmax II GP-compound radials provided the level of grip we were after, and did so lap after lap after lap.
You can toss out all lap times previously published for Willow Springs, it's like a whole new track following its recent resurfacing. This may help put times into perspective: Last year, Canet went fastest on the CBR600F2 at 1 minute, 32.55 seconds, whereas with this year's lot his 1:29.83 lap on the F3 was slowest of the three bikes-but not by much. Canet's best lap on the YZF was a 1:29.81, while his quick est of the day, a 1.29.70, came on the ZX-6R. Just 13/lOOths separated the three-close enough to call it a stand-off.
Both testers praised the 6R for its unmatched stability and strong brakes. Canet felt he was able to drive the Kawasaki deeper into Turns 2 and 9, ultra-fast sections where the bike is in a full-tilt lean at triple-digit speeds, the front wheel car rying much of the load. Here, the 6R's front end felt more settled while giving the most feedback. Corner clearance was the best of the lot, and steering, while slightly heavier than the others, felt more precise. Still, Toland's best ZX-6R lap of 1:29.17 came short of his performance on the other two bikes. If not for the bike's nagging carburetion prob lems, both riders agreed they would have gone substantially quicker on the Kawasaki.
The case with the CBR600F3 was quite the opposite. Carburetion and power delivery, like the YZF's, were very smooth and predictable. The Honda's brakes matched those of the ZX-6R in power and consistency, although the initial bite was a bit too sensitive for Toland's taste. The limiting factor with the Honda focused mainly on front-end woes, and, to a lesser degree, cornering
clearance. Canet experienced a fair amount of high-frequen cy headshake over minor bumps entering Turns 1, 2 and 9, and at the top of the Turn 4 horseshoe. Having tried a range of preload and rebound-damping adjustments with minimal improvement in either lap times or feel, Canet handed the bike off to Toland. The endurance champ lowered the front end, pulling the fork up 5mm in the triple-clamps, then pro ceeded to burn off a tank of fuel and most of the front tire's right-side tread. The effort paid off with a 1:29.00 well into the stint, and although the front continued to patter over the same sets of bumps, much of the headshake had vanished.
Now fora surprise. In an unforeseen ambush changing the course of the war, Toland set the outright fastest time of the day, a 1:28.89, while on the YZF600. Toland attributes the YZF's success to the fact it was the only bike he could hold wide-open through Willow's top-gear Turn 8. Despite the Yamaha's shock not being as well damped as the others, allowing the rear to lightly pogo and cause a slow wag through the bars, its crisp carburetion and linear power delivery proved very valuable allies on the roadcourse.
We must also mention the YZF's front brakes, criticized last year for having a non-linear servo effect-increasing in power over the course of a moderate to hard stop. This year, the problem wasn't evident early on, allowing both riders to brake deeper into Turns 1 and 3 than with the other two bikes. After a couple of dozen hard laps, though, the system took on the same undesirable servo effect as experienced in the past. Once cooked, the pads performed poorly, even on the street ride that followed.
Pulls on the dyno confirmed the Kawasaki was down 5 peak horsepower to our first 6R testbike. Likewise, the F3 made 3 peak horsepower less than before, but maintained its wonderfully broad torque curve. The YZF showed a gain of 2.5 peak horsepower compared to last year’s bike, and while its torque curve isn’t as flat as the F3’s, it makes more peak torque than the other bikes.
With the rigors of the dyno and track testing behind us, and the war-torn Sportmax Ils swapped for fresh Battlax skins, a group street ride marked the 600s’ return to civilian duty. Kawasaki had recalled our 6R for a day, giving the carburetion a tweak by installing updated carburetor needles (these will be fitted to all ZX-6Rs). We immediately noticed a marked improvement in throttle response and carburetion throughout the rev range.
As capable as these bikes are in a pure performance environment, all three adapt quite well to daily in-town and commuting use. All offer well-balanced ergonomics-there’s not an uncomfortable seat or an unbearable reach to the bars among the three. All offer adequate wind protection and have rear-view mirrors that serve their intended purpose well. They all shift smoothly and produce very little vibration at freeway speeds, the YZF and 6R being a bit smoother than the F3. Working any of the three through your favorite set of twisties is pure delight. Each requires a fairly light touch and exhibits neutral steering. The F3 tends to stand up under braking more so than the others, but at its worst, the effect was not bothersome.
What’s war without a victor? Finishing third-and a very close third-in this Supersport Shootout is Yamaha’s 600. While offering a substantial $900 savings over the ZX-6R, the $6999 YZF showed it's still got the stuff on the racetrack, despite a horsepower deficit. And here’s something to ponder: Reinforcements are on the way in the form of a 1996 model with fully adjustable suspension front and rear. Already released in Europe, it should be here mid-year.
At $7299, the CBR600F3 stands the middle ground in both price and performance-it was second overall quickest at Willow Springs, and second to the 6R in top speed. At the dragstrip, the F3 succeeded in kicking the Kawasaki when it was down, but we feel confident that with the 6R's improved jetting, the tide would turn. The street provided a near stalemate between the F3 and 6R, but the ZX-6R gets the nod.
The state of our Kawasaki ZX-6R caused a bit of early confusion-this bike clearly wasn’t as crisp and clean-running as our original testbike. But the $7899 6R still gets our nod as the year's top middleweight Dog of War. Unmatched in outright speed and stabil ity-and. yes, in sticker price, too-even our rough-running 6R held its own throughout the fight and. once rejetted, the Kawasaki asserted its superiority.
End of hostilities, advantage to Team Green. S3
HONDA
CBR600F3
$7299
KAWASAKI
ZX-6R
$7899
YAMAHA
YZF600
$6999
HORSEPOWER! TORQUE
