The Kawasaki ZRX1100 was a standard or sport motorcycle made by Kawasaki from 1997 to 2001. It replaced the Zephyr 1100. Since the Zephyr 1100 sold poorly in the US, the ZRX1100 was not initially sold in that market until 1999.[1][2] In 2001, the ZRX1100 was replaced by the larger engined ZRX1200. The 1100 and 1200 were also sold in the US until 2005. They are still sold in Japan as the ZRX1200 DAEG model.[3]

The ZRX1100 and the later ZRX1200 were styled like 1980s muscle bikes, which were large bikes with large engines. They also were considered Universal Japanese Motorcycles.[1] The Suzuki Bandit 1200 has been credited with leading this niche, taking a large-displacement race replica sport bike and detuning the engine for greater low-rpm torque and easier riding, replacing the aluminum frame with steel, and leaving off the full fairings, lowering cost while losing road racing focus in favor of all-around street sport riding.[4] One of the colour schemes replicates Eddie Lawson's 1982 and 1983 AMA Superbike Series-winning Kawasaki GPZ1100s.[2][5] There were several models, such as the R which had a bikini nose fairing, with a square headlight.

Kawasaki ZRX1100: GREEN MEANIE

Flashback to 1981, when superbikes were 1000cc, made 145 horsepower and wobbled enough to make spectators back away from the fence. Yoshimura was using every trick in the book (and then some) to give Wes Cooley a power advantage with the Suzuki GS1000, and the Honda sledgehammer was in full swing with Freddie Spencer aboard the CB900F. The Kawasaki team was a comparative ball-peen, but they had the tenacious Eddie Lawson riding and a new guy named Muzzy running the show. The championship came down to the wire at the season-ending Daytona round, and Lawson emerged victorious over Cooley and Spencer in a fabulous David vs. Goliath season.

Kawasaki commemorated the occasion by releasing the KZ1000R the following year. The R-model was a collection of KZ1000J and GPZ1100 parts covered with the trademark lime-green paint, and its retail price was "set by dealer." It immediately became a collector's item; some of the bikes never turned a wheel. Performancewise, the R-model was a hit. Substantially lighter than the standard J-model, at 514.5 pounds, and sporting a Kerker pipe, Motorcyclist's ELR (Eddie Lawson Replica) test bike turned an 11.564-second quarter-mile time at 116.12 mph.

However, die-hard race fans will argue the real Eddie Lawson replica is the KZ1000S (which was also sold in 1982 but with a production run of only 30 units). The S-model was a true superbike racer-from its big front brakes on magnesium wheels to the twin-plug head and smoothbore carbs-and it pumped out almost 140 horsepower. In fact, both Lawson and new recruit Wayne Rainey used the S-model superbikes in 1982, with Lawson winning the title again. The bike was a bargain at $10,999, and many a privateer made a name for himself on the big Kawasaki.

One look at the ZRX1100, and the memories come flooding back. Big discs and black, three-spoke wheels-along with the braced aluminum swingarm complete with eccentric adjustment-make this, in some ways, more of a faithful replica than the original KZ1000R. But enough reminiscing....

The heart of the ZRX is its 1052cc motor which is based loosely on the ZX-11 mill, although it has been tuned for more of a midrange punch rather than top end. A similar process was used for the mid-'90s GPz1100 (ZX1100-E1), which combined a detuned ZX-11 motor with a budget chassis and GPz-style bodywork. A lower compression ratio (10.1:1 vs. 11.0:1) combines with less lumpy cams, more flywheel effect and smaller (36mm vs. 40mm) carbs to give the ZRX a flat torque curve. A gear-driven counterbalancer quells secondary vibration, and a five-speed transmission (one less cog than the ZX-11) is utilized. Cosmetically, the valve cover has been polished to emphasize the dual-overhead-cam layout, polished cylinder fins have been added (although water-cooling is used), and the engine side covers have polished fins as well.

The end result of the tune-down is a motor that makes more than 60 foot-pounds of torque from as low as 3000 rpm, peaking at 71.5 foot-pounds just under 6000 rpm. While the peak number is down slightly from the ZX-11 (at 78 foot-pounds), the spread is wider and smoother. The downside of all this is the fact that the torque curve falls off fairly early at just 8500 rpm, severely capping the ZRX peak horsepower at 96.8.

The engine is housed in a double-cradle tubular-steel frame, which has a removable aluminum downtube to ease engine removal. Don't let the old style tubes and dual shocks fool you into thinking the ZRX uses old technology in the chassis though. The backbone tubes have a whopping diameter of 41mm, and both the piggyback reservoir shocks and the 43mm fork (which looks like it has been lifted from the ZX-11 except it is a cartridge-style unit) are fully adjustable for compression and rebound damping, as well as preload. Stopping power is modern, with twin six-piston calipers working on 283mm discs up front, and a single disc at the rear. Wheel sizes and rubber are totally up-to-date also, with Bridgestone BT57s running on 17-inch wheels, 3.5 inches in front and 5.0 inches out back.

Starting the ZRX from cold is a simple affair, but it's worth letting it warm up before riding, as there's a slight flat spot just off idle until things heat up. Once warm, carburetion is excellent, with only a hint of the lean spot remaining. Clicking into first gear is a bit clunky, enough to make the bike lurch when it's cold. Once broken in, the five-speed box worked great, and we can't say enough about Kawasaki's neutral finder. The monster low-end torque and the slick shifting tranny make it easy to beat traffic from lights while only using the bottom third of the tachometer. The 25 degrees of rake and 104mm of trail make for light steering, especially considering the gauges and fairing are mounted to the fork. Low-speed maneuvering is a little tricky though; the big Kawi is a bit of a porker at 545 pounds wet and the center of gravity feels fairly high. Overall, the ZRX is a blast to ride around town, making even the trip to work an enjoyable affair.

A real handlebar and a wide, softly padded seat make for a fairly upright seating position, which is comfortable for about 40 minutes. After that, the forward-sloping seat results in a sore butt and the taper of the bar puts excess pressure on your outer wrists. The passenger seat is quite comfortable, although the rear pegs are set a little high for long legs. The mini fairing does a surprisingly good job of providing wind protection, with the upper chest blast being easily manageable up to approximately 80 mph, at which point it's wise to start crouching down a bit. Handlebar-mounted mirrors provide a good view, but because they are mounted more rearward than if they were on the fairing, their placement is beyond the rider's peripheral view and you have to turn your head quite a bit to use them. At highway speed, they (along with the bar) start to buzz and the reflection gets blurry.

As delivered, the ZRX suspension is soft and plush, with the fork on the bouncy side. Shock and fork adjustments are easy to make. The shocks have a stepped ramp for preload adjustment, along with four-position dials for both rebound and compression damping. It takes only thirty seconds to get the rear boingers working quite well for either a soft freeway ride or a twisty mountain road. The fork has familiar threaded preload adjustment, along with damping adjusters which require a screwdriver. Attempting to stiffen things up with the adjusters results in a harshness over small bumps, and still not enough high-speed damping to cope with large dips. The fork is fine for smooth city streets or freeways, but it could use thicker oil and heavier springs to better tackle the rough Los Angeles urban jungle and bumpy mountain roads.

Front binders are nothing short of spectacular, with the six-pot calipers providing lots of bite along with great feel. However, sudden application causes significant brake dive with the soft fork. This is a bit unnerving, especially if a panic situation occurs. The rear brake is also excellent, providing enough stopping power to slow things down, but not enough to lock the wheel too easily.

Compared with a mainstream sportbike, the ZRX can hold its own quite easily at a moderately quick pace. The wide bar gives a lot of leverage and good feedback from the chassis, and the Bridgestone BT57s provide excellent grip and feel. Once above parking-lot speeds, the 1100 seems to shed about 75 pounds off its wet weight, and can be tossed into turns easily. It's only when the road gets rough that the soft suspension puts an end to the party, as this sets off a wallow in the chassis which is fairly disconcerting.

The torque of the motor makes for great corner exits, and with the upright riding position there's a heightened sensation of the power. It's only when the road opens up and triple-digit speeds are approached that the lack of top end comes into play. Above 8500 rpm there's not much action, and with only the small fairing to help with aerodynamics, it makes keeping up with the sportbike crowd difficult. That's not what this bike was meant for though, and it would be tough to trade off the monster torque that's so much fun around town (and at reasonable speeds) for a burst of top end that would be used only once in a while.

There's no doubt the ZRX is an attention-getter. The retro look and flashy paint make for great "eye candy," as one tester states. And it's hard to stop yourself from turning around to ogle this bike as you walk away from it in the parking lot. Overall, it's a huge amount of fun, and it's impossible to remove the big, cheese-eating grin from your face as you're riding along and thinking, "Freddie who? Wes who?"

Sport Rider Opinions

Just like practically every other streetbike junkie who has been paying attention these last couple of decades, I lust over original Eddie Lawson Replica Kawasakis. Like '79/'80 Honda CBXs or Suzuki GS1000s, ELRs are, for me, the classic sporting motorcycle. So I'm riding into work the other day, and as I park the ZX-9R in the garage I see a lime-green ELR parked alongside the rest of the Motorcyclist/Sport Rider test bikes. I walk over for a better look, certain I'll be wowed. I am-but as I scan the thing I notice an also-green ZRX1100 parked nearby. And after a minute or two, I end up admitting to myself that, sure as hell, the ZRX looks pretty dang good in comparison. It's no ELR, and it's probably never going to be worth 15 grand (OK, maybe in 100 years), but with nearly 100 rear-wheel horsepower, a thoroughly classic look, all the refinement of a late-'90s Japanese motorcycle and about three times the functional competency of the ELR, it's one of the few real keepers of this decade. I could own one of these.
-Mitch Boehm

I was just a dumb teenager at the time, but I'll never forget going to the AMA Nationals in the early '80s with my brother (who was racing in the 250 GP class) and watching Eddie Lawson stick it to the Honda boys on his big green meanie in the Superbike tussle. I lusted over the S-model KZ1000. It looked way too cool with that swingarm, those Dymag wheels and huge discs. Of course there was no way I'd ever be able to own one, but it was nice to dream.

Some things never change. I'm still a stupid kid at heart, and I still think the S-model is one of the greatest bikes ever. The ZRX brings back all those teenage memories, and the way Kawasaki has combined the old superbike look with updated styling and performance is just awesome. I always get a thrill when I ride the 1100, because I start thinking of the big 1000cc superbikes, and it's probably as close as I'll ever get to my teenage dream.

And it works great to boot. While it's not on par with current sportbikes, Kawasaki has done wonders with twin shocks and a tubular steel frame, and the torque spread of the motor makes it a blast to ride. However, I was disappointed with the lack of top-end power and the excess poundage; the performance numbers and weight are similar to the KZ1000R of 15 years ago-a bit of a letdown. Still, it's a great bike. I just wish there was some way to sit and stare at it while I'm riding.
-Andrew Trevitt

As a sportbike fiend whose formative riding years were spent on bikes like those in the Kawasaki GPz series, it's great to see a manufacturer go back to its roots, but with the added pizazz of today's performance technology thrown in. In a world of ever-increasing aerodynamic emphasis, it's nice to see a bike with the stark, rugged simplicity of the ZRX1100. The Kawasaki's big powerplant, braced swingarm and scalloped seat bring back memories of one of my all-time favorite roadracing photos: Eddie Lawson in a full-lock slide as he powers the big Kawasaki out of a left-hander.

And unlike previous attempts by other manufacturers to build a "retro-standard" superbike, Kawasaki has backed up the macho look with some decent steam. Using the ZX-11 motor was a natural move, and it allows a rider to boost power to even higher levels with the plethora of hop-up parts available on the market. I'm not a big fan of the five-speed tranny, though. I never looked at the ZX-11's six-cogger as a nuisance and the gearing puts the rpm right on the vibration point at highway-cruising speeds. But everything else is topnotch. The suspension's full adjustability is a welcome modern update and the six-pot front binders provide good stopping power. And all this for a price of $7199? No wonder the ZRXs are nearly gone from dealerships already.
-Kent Kunitsugu

Test notes
+ Awesome torque down low
+Gorgeous, simply gorgeous, styling
-A bit of a porker at 545 pounds wet
-Boingy fork could do with thicker oil and heavier springs
XHow about some real ELR power?

The Doctor is in Japan

Kawasaki's ZRX1100 may be new to the States, but it's already been available (and a hot seller) in Europe and Japan for a few years now. And since the motor is basically a ZX-11 powerplant detuned for midrange lunge, it took all of about two seconds for speed merchants to come up with a plethora of parts to boost power levels far beyond stock.

Probably the most outrageous ZRX we've seen is the pet project of a performance shop in Japan called Doctor Suda. Utilizing their extensive experience with beefing up Kawasakis of various pedigrees and displacements, the surgeons at Dr. Suda immediately dove into the ZRX motor's internals. Their Stage-4 kit consists of a set of balanced 2mm overbore JE pistons and a crankshaft stroked out an additional 5mm (boosting displacement to 1205cc). A bank of Keihin flat-slide 37mm FCR carbs supply mixture into the ported cylinder head running ZX-11 cams, with Doctor Suda's handmade Project-328 exhaust (named after its Bonneville project ZX-11 that ran 328 kph [203 mph] in 1994) flowing the spent gases. Extra horsepower means extra heat, so a monster radiator pirated from a ZX-7R was grafted on, while the ZRX's stock five-speed tranny was ditched in favor of the original six-speed ZX-11 unit. Chassis mods include a Race-Tech Gold Valve-equipped fork, with Dynamic Suspension of England revamping the stock ZRX piggyback shocks.

Doctor Suda labels its performance kits with the "IPTOS" acronym, which stands for "Ideal Power Tuning On Street." The dyno graphs the company sent to us seem to illustrate that philosophy. Although the ZRX monster peaks at 158 horsepower at 10,000 rpm, with an incredible 97 foot-pounds of torque at 7500 rpm, the real kicker is the graphs. The torque climbs to 91 foot-pounds at 3500 rpm then remains nearly billiard-table flat up to the rev-limiter, while the horsepower graph is so linear it looks like a misprint. This translates into a descriptive phrase we thought we'd never use: usable mondo horsepower.

The Doctor Suda accessories catalog is available, although much of it is printed in Japanese. But if you're interested in some very trick parts and services for your ZRX, it's worth a look. We'd suggest making inquiries via fax, unless you're fluent in Japanese..