It combined big-bore power with sport bike handling, but, crucially, it also pioneered meticulous attention to weight-saving design.

In every North American destined Kawasaki motorcycle owners manual from 1989 - 1995 is the wording "Blends of gasoline and alcohol called “gasohol” can be used on an occasional basis, however continued use is not recommended."

In 1996, Kawasaki broadened that language to "Gasoline frequently contains oxygenates (alcohols and ethers) especially in areas of the U.S. and Canada which are required to sell such reformulated fuels as part of a strategy to reduce exhaust emissions...Operating problems that result from the use of poor quality or nonrecommended fuel may not be covered under your warranty...Never use gasohol containing more than 10% ethanol (grain alcohol).

From 1998 onward, including 2023 Kawasaki motorcycles, it was broadened further to read "Gasoline/Alcohol Blends - Gasoline containing up to 10% ethanol (alcohol produced from agricultural products such as corn), also known as “gasohol” is approved for use: 15% MTBE, 16.7% TAME, 17.2% ETBE, & 5% Methanol."

Unlike its competitors, Kawasaki chose to make two variants of many of their 1980, 1990 and 2000 era carbureted motorcycles, including each model ZX-9R.

The wheels - three-spoke cast aluminium alloy 3.5-inch x 17-inch front and 5.5-inch x 17-inch rear -, the front forks - fully adjustable 43 mm upside-down KYB - and unbraced fabricated aluminium box-section swingarm with fully adjustable remote-reservoir KYB monoshock were direct carry-overs from the ZXR.

The crankcases, clutch and gearbox were carried over from the ZXR750, with a longer-throw crank and a bigger 73mm bore, 53.7mm stroke and 11.5:1 pistons, taller cylinder block for the larger capacity.

Induction was by 40 mm Keihin CVKD carburettors, and the engine breathed through a 10-litre airbox fed by dual ram-air intakes on the nose of the bike, under the single headlight, via ducts passing back and over the frame beams near the steering head, like on the ZZ-R. For the 1996 ZX-9R B3 model forward, with exceptions to B3/B4 49-state variant equivalents for Austria and France, Keihin carburetor jetting sizes and components within each generation of ZX-9R model would remain set with one configuration, sealed by Kawasaki, Japan.

Pillion grab rails were added, the gearboxes were made stronger, and new six-piston Tokico front calipers replaced the previous model's four-piston units.

Kawasaki claimed 143 PS for the 49-state equivalent variant and 141 PS for the 50-state, which by then also included a muffler located oxidizing exhaust catalyst and electronic fuel cut-off valves on the CVKD carburetors (also on D variants) to meet California Air Resources Board's (CARB) evolving cleaner burning gasoline and emissions for fuel evaporation and exhaust.

Labeled "World's First 9 Second Production Sportbike" on the cover of the June 1998 issue of Sport Rider magazine, the Title V permitted 49-state ZX-9R C1 prepped by KHI, California, recorded the now famous uncorrected 9.99 second @ 136.8 MPH 1/4 mile run, with a top speed of 168.1 MPH and a tank range of 216 miles.

The frame lost the steel engine cradles, but also its bolt-on subframe and the rear ride height adjuster.

The front forks were criticised by some European testers for fluttering during hard driving, a phenomenon that was only solved with the 2002 model.

Visually, the new bike retained the rounded look of its predecessor, but became sleeker, with a slimmer tail unit and a smaller fairing.

As a consequence of the smaller engine and shorter wheelbase, though, the fuel tank became wider and intruded more on the riding position than before.

Reviewed in the April 2000 issue of Sport Rider magazine (HQ Southern California), a 49-state KHI, California, prepped ZX-9R E1 sprinted to an uncorrected 10.06 second @ 138.96 MPH 1/4 mile, 173.5 MPH top speed and boasted a tank range of 211 miles.

Increased offset on the triple clamps reduced the trail on the front wheel to make the steering more agile.

The forks were shortened to save weight, and the rear shock top mount was redesigned to incorporate a ride-height adjuster.

Changes to the 2002–2003 ZX-9R included a new tail fairing, a single piece front mudguard, the loss of the passenger grab handles and the B/C/E model H-bar mirror bracket.

Mechanical additions included a top braced swingarm (claimed 20% stronger) and rear shock with a side facing fluid reservoir, stiffened frame with relocated solid engine mounts, increased trail and reduced fork offset, and new Nissin four-piston caliper brakes and 320 mm discs at the front wheel.

[15] California-specific evaporative emissions control (EVAP) models included two-stage exhaust catalytic converters,[16] two additional fuel tank fuel vapor recovery plumbing tubes fed to an under tank charcoal canister, an evaporative emission purge control valve incorporated into the Y-snorkel RAM air system float bowl equalization plumbing, and carburetors with electronic fuel cut off solenoids.