Motorcycle.com

In AMA Superbike, Mr. GSX-R gets to keep all four 42mm cake holes wide open. You're not allowed to fool with the stock crankshaft, though. Valves have to be the same material as stock, ie. steel, and cams can have no more lift than stock.

Unfortunately for the competition, steel valves aren't what limits the mighty GSX-R's rpm. The poor long-stroke dear's bores are only 73mm wide. Heck, that's only one mm bigger than the GSX-R750, and only 5mm bigger than the new 636 Kawasaki.

What does limit the GSX-R is piston speed, since its 59mm stroke isn't all that much shorter than an RC51 Honda's 63.6mm.

"With valves not that much bigger (or heavier) than those bikes' either, there's nothing in the big GSX-R's valvetrain to keep it from spinning past 15,000 in stock form, just like the 636."

Connecting rods, according to our sources at Attack Suzuki, are the weak link in the GSX-R, and as the rulebook doesn't address those items, you can be sure those fast factory GSX-R's have the nicest, lightest ones money can buy, pumping lovely 73mm pistons. At that point, it's Hello, 15,000 rpm (plus), and Goodbye, bikes trying to process the same volume of air with a pair of 100mm pistons.

Hey, if Mladin's old 750 was so dang slow, how'd he win the three championships on it? Well, I hate to say I told you so, because I actually managed to hold my tongue for once--and when the GSX-R's didn't dominate Daytona, I thought there was a slight chance I might have been, gasp, wrong. Ensuing events, including watching Mladin's GSX-R1000 leap off the corners at Sears Point, have led me to have renewed faith in my own infallibility.

Nevertheless, we took it upon ourselves to conduct further experimentation. Aprilia's Mille R, winner of last year's MO Twins shootout, is new and improved for `03 with radial brakes, a revised tail section, and, and, that's all.

And while we were at it, why not take along the very Kawasaki ZX-6R that won the track portion of our recent 600 Shootout, the bike that's carried little Tommy Hayden to victory in every AMA Superstock race run this year? (Bearing in mind that last time we ran a 600 against an Open-class bike [R1] and a twin [Aprilia Mille R], the little Yamaha R6 was right in the thick of things, and in fact ran the fastest lap of the day at the Streets of Willow Springs.)

Once again to Circuito AMA at California Speedway in beautiful Fontana, courtesy of our best friends at fastrackriders.com. (People who call it "Fontucky" have obviously never been to Kentucky.)

Fresh Pirelli Diablos for everyone, courtesy of our other best friends Tom and Jerry at California Race Services (714 305 6846). Once again into the breeches, er breech...

1. John Burns, MO Editor/Cruise Director
Bias: None Whatsoever

Ooooh, ooooh, me first. The Mille R is a beautiful motorcycle, and whoever called it an Italian Kawasaki the other day must never have seen one in the flesh. (Actually, Kawasakis are looking pretty damn good these days too.) Aside from the new radial brakes, changes for the `03 version are cosmetic: blacked out frame and swingarm, and a reshaped tail section.

Other than that nothing really needed changing; Ohlins suspension and steering damper, and light and beautiful OZ wheels are standard equipment. Really what the Mille needs is more power. On tighter circuits or the road, 111 horsies are usually plenty, but on Fontana's long straights, a few more would be most welcome.

On a day with a stiff easterly breeze, the Mille could only pull itself up to an indicated 139 mph running into the teeth of that gale, down Fontana's long, banked main straight. Other than a relative lack of steam, nothing else about the Mille R merits complaint. In my normal fashion, I rode the Mille to Fontana that morning, and it's just as pleasant hauling mail as it is dragging knee.

Wolf down an Egg McBolus, add more gas and get on with it. All three of these bikes have radial brakes, and I think the Mille's give the most feel and controllable power--but that could be because the GSX-R was steaming into corners with quite a few more knots. I won't bore you again with what an overall nice conveyance the Mille is, how thin and lithe between the knees...

And the ZX-6R, which makes damn near as much power as the Mille and weighs less, is a fine track tool unto itself.

Had I ridden the little stinger missile out to the track that day, however, I doubt I'd have arrived in such an expansive, congenial mood.

Alas, I'd need to get back on the Paxil to ride this one every day.

"As a streetbike, the GSX-R1000 falls somewhere in the middle, with far superior street suspension and seat foam than the Kawasaki, but still requiring a bit of a stretch to get to the clip-ons."

Once on track, I'd still rate its ergoes behind the other bikes, but none of that stops its 150-horsepower engine from blowing them into the weeds. And here's the crux: You know what I think all of a sudden tilted the playing field in favor of the big four-banger lately? Do you? Sad to admit, I've actually given this some thought. I think modern, computerized fuel injection/ignition timing has turned the tide, has taken away the twin's advantage.

Everything I've read and felt with my own pair of buttocks over the years tells me the twin-cylinder advantage was always its ability to put the power down early exiting corners (a thing 600's are good at too, with their near absence of torque compared to both the bigger bikes here).

Once upon a time, when there were only carburetors, it was actually fairly easy and common to spit a liter-bike's rear tire out from under yourself by getting on the gas too soon or just too awkwardly--a thing made all too easy if imperfect carburetion caused a sudden spike in power delivery. Even just a small glitch on a powerful bike, if you happened to be near the edge of traction, could spell disaster. Have you noticed, or is it just me, that that really doesn't happen so often anymore? I haven't seen a good old-fashioned Scott Gray highside/cartwheel into the hay bales since Scott Gray retired. With the advent of programmed fuel injection, ignition curves for every gear, the throttle position sensor, etcetera etcetera, you can almost ride the GSX-R1000 as our friend Pauly Carruthers advises us to ride CBR600s at Las Vegas. "Just whack it open man. What could happen?"I'm serious. I was at the press launch of the, what year was it? `94 GSX-R1100 at Laguna Seca? Could've been `95... The press corps crashed two of them that I can remember, and there but for the grace of God went I on several sideways occasions. In contrast, at the recent launch of the new 1000 in Australia, we didn't lose a single bike--and the new 1000 is so much faster than the old 1100 it's not even humerus.

It was an interesting day for making comparisons. Steady 35/40 mph wind with gusts to 55/60 mph provided a very unusual perspective. The new GSXR1000 feels smaller and again lighter than last year's bike, it is noticeably narrow through the tank, less stress on the old hip joints.

The power delivery is more controllable than I remember--could be the suspension is mo better and that allows one to throttle up sooner, without as much intimidation as the 2002 bike. This said I had a hard time going fast on the thing.

The major reason for this is FEAR! Two things kept me off my pace. First, I was experiencing closing speeds into my braking points that were amazing. I didn't get the seat time to adjust to these velocities. Second, the wind was knocking me waaay off line. It would push me four or five feet off line on the banking at an indicated 165. I don't know why, it just caused me to let off a bit! On the AMA track at Fontana the Suzuki's power is staggering. I concur with almost everyone else out there; the GSX-R is still the best open-class repli-racer under $17,999. I need to borrow this one for a few more track days. All that said, I went fastest of these two on the Suzi.

The new for `03 radial-mounted Brembo brakes are as fun as the Suzuki's motor: one-finger power at any speed, linear in application, and boy they look cool too.

Power delivery is typical V-twin--lots of torque to pull you off the corner and nice top end to get you quickly to the end of whatever straight you happen to find yourself on. I've ridden these bikes with the factory "off highway" exhaust, derestricted intakes, and a power chip, that takes them up to near 122- 126 hp--mods I highly recommend.

In the wind, this stone-stock Aprilia could just get up to 140-something, with less side-wind effect than on the Suzuki. The Mille didn't scare me so bad, but the Suzuki's power had me running quicker laps.

We were also fortunate to have the two new Kawasaki 600-class bikes to sample: The ZX-6RR and ZX-6R (636). Maybe size does matter, or does it?

I went faster on the 636 compared to the 600, but turned my best lap of the day aboard the 636 over the GSX-R and the Mille as well. I admit I am a 600 class fan. This new Kawasaki was my favorite last month in MO's 600 comparo. It flat rips! The only improvements I would recommend would be 1. A steering damper, 2. brake pads with a bit less initial bite, 3. revalved suspension, (it's a tad on the harsh side and the front lacks feel). At that point I think you'd have the best club racer possible this year.

All these bikes are equipped with the latest fuel injection systems and none showed any sign of switchiness, surging, or hesitation during throttle inputs. Carburetors have been around for ever--over 100 years-- that's a lot of development time. In about a tenth of that time, it is really amazing how quickly motorcycle FI technology has developed.

3. Sean Alexander MO Patience-Testing Editor
Bias: former factory Kawasaki rider

It was with much trepidation that I opened the GSX-R 1000's throttle at California Speedway. You see, I've never ridden an open class sportbike, oh sure, the occasional Bandit 1200, ZRX, Speed Triple, FJR 1300, etc. passes between my legs, but never a mega-horsepower race replica. Turns out, I needn't have been so concerned.

The GSX-R 1000 is a pussycat when ridden with a dose of respect for its 157 horsepower, a Big, Stable, Neutral Steering Tabby that only wants to inhale straights and small children.

"After my first session, I came in and remarked to Will Tate that I was afraid of using anything more than gentle throttle twists off of the corners."

Will said "Yeah right, you were painting black lines all over the racetrack" Could have fooled me, the big GSX-R was so stable and calm I had no idea the tire was spinning. That stability (at least in stock form) also acted to make the GSX-R slower through Fontana's numerous chicanes, though it did have a calming effect on my soul, and a calm soul is a good thing when you slam on the brakes (at an indicated 172mph) and flick left for the big chicane on Fontana's front straight.

The GSX-R was the second fastest bike for me, lagging half-a-second behind the ZX-6R. With some more seat time and another set of tires, I would have been fastest on the big Suzuki.

This particular Mille felt a little "off" to me. Perhaps it is just a product of being in completely stock (read restricted) tune, or perhaps we just got a particularly slow example? Whatever it was, the Mille was the slowest bike for me by a large margin.

Aside from power, the Mille R was its usual stable, reassuring "unflappable" self. As with most Italian twins, the Mille feels very much at home, on the racetrack and I think it's the one that would be easiest for a novice to ride without crashing.

Ah yes... haven't we met before? The Kawasaki ZX-6R and I have had a loving friendship for the past few months. Aside from it's stock suspension and a tendency to shake its head, the ZX-6R is just about the perfect track bike, for any track this side of Daytona. Of course priced at eight Grand, the Kawasaki could receive a top of the line steering damper and suspension tuning, while still being way cheaper than the other two bikes in this test.

Though the Suzuki is undoubtedly faster, this little 600 is more accessable and was easy to go fast on, right out of the box.

At Fontana, even with stock suspension and no steering damper, the ZX-6R cut the fastest lap time, while spotting 20 mph to the GSX-R on the banking.

It also sounds the best and on tight racetracks it's one of the fastest street legal vehicles you can get, regardless of price. For my money, the Kawasaki takes the prize as the best of the best.

The Conclusion!

Allow me to interpret the results if I may: Neither WT nor SA had ever ridden a liter-bike on a track before--SA had never been on a liter-bike period, and I think the GSX-R's reputation just preceded it.

With more track time (there's never enough), I tell you without a doubt both of their results would've resembled mine, relatively speaking that is.

We, okay I, hereby crown the Suzuki GSX-R1000 the Performance King of 2003, extend our congratulations to Mat Mladin on his fourth AMA Superbike championship, and look forward to a much more interesting season in 2004, when we hope to see new big fours from Kawasaki, Honda and Yamaha. Barring, of course, another eleventh-hour wigged-out change in the rules...

Learn something from this. All that good-soldier, suffer-in-silence stuff that used to be thought of as noble and a sign of character until the day after the Battle of the Somme, approximately, is totally for the birds in modern times. Making it to the top requires talent, but there's really no substitute for a big mouth and the willingness to articulate one's grievances. I mean that in the most sincere way.