Kawasaki Ninja ZX-7R
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| Manufacturer | Kawasaki Motorcycle & Engine Company |
|---|---|
| Also called | 1989 to 1995 ZXR-750 - ZXR-750R 1989 to 1995 US ZX-7 - ZX-7R 1996 to 2003 ZX-7R - ZX-7RR |
| Parent company | Kawasaki Heavy Industries |
| Production | 1989-2003 |
| Predecessor | GPX750R |
| Class | Sport bike |
| Engine | 748 cc (45.6 cu in) four-stroke, liquid-cooled, 16-valve DOHC, inline-four |
| Bore / stroke | 73.0 mm × 44.7 mm (2.87 in × 1.76 in) |
| Compression ratio | 10.8:1-11.5:1 |
| Top speed | 241–262 km/h (150–163 mph)[1][2][3] |
| Power | 77.6–81.4 kW (104.0–109.2 hp) (rear wheel) @ 11,500 rpm[3] |
| Torque | 71.0–76.5 N⋅m (52.4–56.4 lb⋅ft) (rear wheel) @ 9,000 rpm[3] |
| Transmission | 6 speed manual, slipper clutch |
| Frame type | Aluminum twin-spar |
| Suspension | Front: adjustable 43 mm inverted cartridge fork Rear: Uni-Trak (monoshock) swingarm |
| Brakes | Front: twin 320 mm (13 in) semi-floating front discs with Tokico six-piston calipers Rear: 230 mm (9.1 in) disc with twin-piston opposed caliper. |
| Tires | 120/70ZR17, 190/50ZR17 |
| Rake, trail | 25.0°, 3.9 in (99 mm) |
| Wheelbase | 1,440 mm (56.5 in) |
| Seat height | 780 mm (30.9 in) |
| Weight | 210 kg (460 lb)[1] (dry) 235–239 kg (518–527 lb)[3][4] (wet) |
| Fuel capacity | 18 L; 4.0 imp gal (4.8 US gal) |
| Oil capacity | 3,600 ml (3.8 US qt) |
| Related | Kawasaki ZXR250 Kawasaki ZXR400 Kawasaki Ninja ZX-6R Kawasaki Ninja ZX-9R Kawasaki Ninja ZX-12R |
The Kawasaki Ninja ZX-7R was a motorcycle in the Ninja sport bike series from the Japanese manufacturer Kawasaki produced from 1989 until 2003. Kawasaki used inverted forks starting in 1991, added ram air using a single tube in 1993, and in 1996, twin tube ram air and Tokico six piston brakes and fully adjustable suspension.
From 1989 through 1995 in the US market, Kawasaki called the ZXR-750 and ZXR-750R the ZX-7 and ZX-7R respectively. Starting from 1996 Kawasaki dropped the ZXR name worldwide and the former ZXR-750 was now ZX-7R and the limited edition homologation special ZXR-750R/ZX-7R started in 1991 was now ZX-7RR.[5]
Overview
[edit]The ZX-7R has a 749cc in-line four-cylinder, four-stroke engine.
The frame used on the ZX-7R is a lightweight aluminum twin-spar item, designed using computer-aided design to optimize strength. The rear subframe was constructed using steel, providing enough strength for a pillion passenger.
The swingarm used largely the same fabrication techniques to produce a hollow cast and pressed aluminum alloy hybrid swingarm, and the Uni-Trak rear suspension system features a predominantly lightweight alloy and aluminum construction. The Uni-Trak system was designed to provide a progressively stiffer damping and spring rate under compression. The rear suspension unit is fully adjustable in terms of damping, preload and compression.
Production Years
[edit]ZX-7 (H1) 1989
[edit]The first year ZX-7 was launched in 1989 and received mixed reviews from motorcycle journalists. Some criticized its weight; 30lbs heavier than that years Suzuki GSXR750 and 70lbs heavier that Honda's RC30. Overall it was praised for its approachable handling, albeit with a noticeably stiff rear suspension. [6]
The H1 model produced 107 crankshaft horsepower at 10,500 rpm. The engine has a 68mm bore, a 51.5mm stroke and a compression ratio of 10.8:1. Fueling was accomplished via 4x 36mm Kehin CVKD constant velocity carburetors. [7] Intake air is fed to the air-box through the two tubes run from the front cowling through the fuel tank.
The frame is an aluminum perimeter type. The suspension consists of adjustable 43mm forks at the front and a monoshock at the rear connected to the swingarm with a Unitrak rocker linkage. Front brakes are dual 310mm rotors with 4 piston calipers. The rear brake is a 230mm rotor and two piston caliper. Wheelbase measured 1410mm.[8]
Dry weight was measured at 451.9lbs.
ZX-7 (H2) 1990
[edit]The 1990 model year inherited many of the items in the "race kit" from the prior year. The swingarm, previously a box beam type was updated to be a single cast/welded piece. Engine changes included larger 38mm carburetors, shorter pistons and longer connecting rods. The oil filter, previously an external spin on design was moved to an internal paper cartridge style. The exhaust header, radiator and oil cooler were changed as well. [9] Wheelbase was lengthened by 35mm.
ZX-7 (J1,J2) 1991-92
[edit]For 1991, the ZX-7 received a host of changes. A new shorter stroke engine was introduced with a bore of 71mm and a stroke of 47.3mm. This new engine retained the 10.8:1 compression ratio and 38mm Kehin carburetors from the H2 model. The engine was now utilized as a stressed member of the chassis. These models were deliberately restricted by Kawasaki to 100hp due to fear of a potential Europe-wide horsepower limit.[10] The aluminum perimeter chassis was lightened and equipped with new inverted 43mm forks, and larger 320mm front brakes. The wheelbase was shortened again to 1420mm. This new model weighed roughly 30lbs less than the prior year. [11]
The J2 model received a reduced spring rate in the rear in an effort to make the rear suspension less stiff.
ZX-7R (K1, K2) 1991-92
[edit]The 1991 ZX-7R is the first year of the super bike homologation version of the ZX-7. Many changes made in order to improve performance and usability on the track. The engine was unrestricted and equipped with 39mm Kehin flat slide carburetors, more aggressive camshafts, a higher 11.5:1 compression ratio and a close ratio transmission. This engine produced 121 horsepower at the crankshaft. The steel tank of the ZX-7 was replaced with an aluminum version to save weight. The front and rear suspension is fully adjustable. The ZX-7R can be quickly identified by its single rear seat and lack of passenger footpads. [12]
ZX-7 (L1, L2, L3) 1993-95
[edit]The 1993 ZX-7 is the first model to have Ram-Air, an engine air intake positioned to the next to the headlights on the front fairing. The ram air intake is ducted from the front of the motorcycle, through the frame and into the bottom side of the engine air-box. This system is designed to take advantage of the motorcycles velocity, allowing for the stagnation pressure of air at the front to provide a positive pressure to the engine intake. Another advantage is the cooler air temperatures seen at the front of the motorcycles as compared to next to the engine.
The 1993 ZX-7 inherited the ZX-7R motor from the previous year, minus the flat slides and close ratio transmission. The engine has a bore of 71mm, stroke of 41.7mm, compression ratio of 11.5:1[13] and breathes through 4x 38mm Kehin 38mm CVKD carburetors. The engine produced 118hp at the crank and 54.3 lb-ft of torque. [14]
Chassis improvements include smaller diameter, 41mm inverted front forks, and a revised, more linear Uni-track linkage at the rear. These updates addressed many of the handling problems with the previous models, specifically regarding rear suspension stiffness. The wheelbase was lengthened to 1430mm.
ZX-7R (M1, M2) 1993-94
[edit]The 1993 ZX-7R received the same major updates as the ZX-7, benefiting from the addition of Ram-air. The ZX-7R engine is equipped with 39mm flat slide carburetors and a close ratio 6 speed transmission, producing 121 horsepower at the crankshaft.
One update not received by the ZX-7R was the revised rear shock and linkage, instead the older, stiffer setup was carried over. The front forks had additional adjustability, with 13 way rebound and 8 way compression adjustment. This ZX-7R introduced an adjustable swingarm pivot allowing for more trackside adjustment of the bikes handling characteristics.[15] Like the previous ZX-7R, this model received an aluminum fuel tank for weight savings. The subframe is also smaller to save weight without the need to support a passenger.
ZX-7R (P1-P7) 1996-2003
[edit]In 1996, Kawasaki changed the U.S. naming convention for its 750cc sport bikes. The ZX-7 was now to be known as the ZX-7R and the ZX-7R became the ZX-7RR.
This model year was a large update to the 750cc Kawasaki, receiving an entirely new engine and dual Ram-air inlets. The engine has a bore of 73mm and a stroke of 44.7mm. The rocker-arm style cam followers of previous years was replaced with a direct actuation bucket style, reducing valve train inertia and allowing for higher engine RPM. The throttle pulley was moved from the far right side of the engine to the middle, reducing free play in the throttle butterflies in an effort to stabilize idle RPM. The cylinder head received a wider, 25 degree valve angle compared to the previous years 20 degrees. The larger cylinder bore necessitated the mover to a closed deck cylinder and the cylinder head received oiling and cooling improvements. The exhaust header was updated to be a 4-2-1 style instead of the previous years 4-1.[16] This engine produced 123 horsepower measured at the crankshaft.
The chassis was updated with a stiffer frame, larger 43mm forks with added adjustment for rebound. The rear shock also gained additional adjustability with 20 way compression adjustment and 4 way rebound adjustment. Braking was improved with new 6 piston Tokiko front calipers.[17] Total dry weight was 448 lbs (203kg).
ZX-7RR (N1) 1996
[edit]The 1996 ZX-7RR recieved track focused improvements consisted of larger Kehin FVKD 41mm flat slide carburetors, and a stronger paper based clutch lining. Additional changes were, a quick change camshaft sprocket, close ratio transmission and a heavier flywheel to prevent rear wheel spin while cornering.[18]
The chassis was stiffened with gusseting near the rear of the engine. The suspension received additional adjustability; 28 way compression and 13 way rebound on the front forks and 20 way compression and 18 way rebound on the rear shock. The 6 piston Tokiko calipers on the standard model were swapped out for 6 piston Nissin units. A smaller 8AH battery was fitted. [19]
1996 was the only year the ZX-7RR was sold.[20]
Racing
[edit]The ZX-7RR was raced, winning 12 AMA superbike championships. Kawasaki's Road Racing team riders were Eric Bostrom, Doug Chandler and Scott Russell. Doug Toland won the 1993 Endurance FIM World Championship. Andreas Hofmann won the 1997 Macau Grand Prix.
References
[edit]- ^ a b Ienatsch, Nick (May 27, 2013). "Superbikes With Soul: Classic vs. Modern Superbike Comparison Test". Cycle World. Retrieved October 29, 2016.
- ^ "1996 Kawasaki ZX-7R". Cycle World. March 1996. pp. 43–48.
- ^ a b c d "Performance Index Winter '12/'13 Edition" (PDF), Motorcycle Consumer News, Bowtie Magazines, January 2013, archived from the original (PDF) on 2016-12-29
- ^ "Sportbike Weights and Measurements". Sport Rider. August 23, 2011. Archived from the original on February 23, 2018. Retrieved September 18, 2016.
- ^ Shippey, Mark (October 10, 2010). "Bike Icon: Kawasaki ZXR750". Visor Down. Retrieved April 19, 2017.
- ^ https://issues.cycleworld.com/article/1989/4/1/zx-7
- ^ https://www.motorcyclespecs.co.za/model/kawasaki/kawasaki_zxr750h%2089.htm
- ^ https://www.motorcyclespecs.co.za/model/kawasaki/kawasaki_zxr750h%2089.htm
- ^ https://www.zxforums.com/threads/do-i-have-an-h1-or-h2.208297/
- ^ https://andys-kawasaki-zxr-zx7r-tribute-site.net/model-history/
- ^ https://www.motorcyclespecs.co.za/model/kawasaki/kawasaki_zxr750J%2091.htm#google_vignette
- ^ https://andys-kawasaki-zxr-zx7r-tribute-site.net/model-history/
- ^ https://pws.ktivs.net/assets/manuals/99920-1633-01_EN-3a2b9b56bd8b70768305112dce6a625e/index.html#p=8
- ^ https://www.motorcyclespecs.co.za/model/kawasaki/kawasaki_zxr750L%2093.htm
- ^ https://www.cycleworld.com/sport-rider/how-motorcycle-swingarm-adjustments-impact-traction/
- ^ https://www.youtube.com/watch?v=SzAnaT9WXu8
- ^ https://www.youtube.com/watch?v=SzAnaT9WXu8
- ^ https://www.youtube.com/watch?v=SzAnaT9WXu8
- ^ https://www.youtube.com/watch?v=SzAnaT9WXu8
- ^ https://andys-kawasaki-zxr-zx7r-tribute-site.net/model-history/