Kawasaki ZX-R 750 J1

Kawasaki ZX-R 750 J1
Manufacturer	Kawasaki
Production	1991
Class	Sportbike
Engine	Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.
Compression ratio	10.8:1
Top Speed	241 km/h / 149.7 mph
Ignition	Digital
Spark Plug	NGK, CR9E
Transmission	6 Speed
Frame	Aluminum perimeter
Suspension	Front: 43mm Upside-down forks, adjustable ride height, 13-way rebound Rear: Uni Track monoshock. adjustable ride height, preload, 4-way rebound
Brakes	Front: 2x 320mm discs 4 piston calipers Rear: Single 230mm disc 2 piston caliper
Front Tire	120/70ZR17 /Std Pressure 36psi
Rear Tire	180/55ZR17 /Std Pressure 41psi
Wheelbase	1420 mm / 55.9 in
Weight	195 kg / 420.9 lbs (dry), 221.6 kg / 487.2 lbs (wet)
Recommended Oil	K-tech 10W-40
Fuel Capacity	18 Liters / 4.7 US gal
Manuals	Service Manual

It could reach a top speed of 241 km/h / 149.7 mph.

Engine

The engine was a Liquid cooled cooled Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.. The engine featured a 10.8:1 compression ratio.

Drive

Power was moderated via the Multi plate wet (oil submerged) hydraulic ‘slipper’ clutch.

Chassis

It came with a 120/70ZR17 /Std Pressure 36psi front tire and a 180/55ZR17 /Std Pressure 41psi rear tire. Stopping was achieved via 2x 320mm discs 4 piston calipers in the front and a Single 230mm disc 2 piston caliper in the rear. The front suspension was a 43mm Upside-down forks, adjustable ride height, 13-way rebound while the rear was equipped with a Uni Track monoshock. adjustable ride height, preload, 4-way rebound. The ZX-R 750 J1 was fitted with a 18 Liters / 4.7 US gal fuel tank. The bike weighed just 195 kg / 420.9 lbs. The wheelbase was 1420 mm / 55.9 in long.

Photos

Overview

Kawasaki ZX-R 750-J

The Kawasaki ZXR 750 J (J1 and J2 models) was a 749cc sports bike released  between January 1991 and November 1992.

The ZXR750 J was an updated version of the Kawasaki ZXR750 H1 and H2 models and featured 43mm upside down (USD) forks, lighter, diamond section alloy chassis, new short stroke engine and 38mm CVKD carbs (aka constant velocity carb).

Kawasaki ZXR750J

Model information Bike model: Kawasaki ZXR 750 J Years (in the UK): January 1991 to November 1992 Kawasaki model code: ZX750J Frame number: Started – ZX750J—-

Model and updates….. ZXR750 J1 (ZX750J1): January 1991 to December 1991. Frame number started: ZX750J-000001-. Available in green/blue/white or blue gitane. Cost new (in the UK): £6379

ZXR750 J2 (ZX750J2): January 1992 to November 1992. Frame number started: ZX750J-013901-. Same as the ZXR750 J1 model but with minor suspension modifications and a softer rear shock. Available in green/blue/white or wine red Cost new (in the UK): £6379 (price was reduced to £6249 for a new ‘K’ reg bike)

ZXR 750 J engine

Engine and gearbox Displacement: 749cc (71 x 47.3mm) Engine type: In-line four cylinder Compression: 10.8:1 Power: 100 BHP Top speed: 143.5 mph Stroke: 4 Stroke Oil type: 10w40 Semi synthetic (ZXR750 J Oil filter kit – Rock Oil / ZXR 750 J Oil filter kit – Silkolene) Oil filter: Filtrex OIF006 / Hiflo HF303 / Champion F301 Engine oil capacity: 3.2 liters Valves per cylinder: 4 (16 valves in total) Cam shafts: Double overhead cams (DOHC) Cooling system: Rock Oil Water cooled Cooling system capacity: 2 liters Clutch: Multi plate wet (oil submerged) hydraulic ‘slipper’ clutch Gearbox: 6 speed Gearbox lubrication: From engine (no separate gearbox oil) Carburetors: 38mm CVKD Carbs Air filter: Kawasaki part no: 11013-1210 Service kits: Silkolene / Rock Oil

Chain n’ Sprockets Final drive: Chain (530 pitch chain with 110 links) Front sprocket teeth: 14 Rear sprocket teeth: 46

ZXR750 J Radiator

Servicing intervals Oil change: 10,000km (approx 6200 miles) or every 12 months Cooling system change: Every 24 months (2 years) Hydraulic brake fluid change: 20,000km (approx 12,400 miles) or every 24 months (2 years) Fork oil change: 30,000km (approx 18,600 miles) or every 36 months (3 years) Swing arm pivot and uni-track grease points: Grease every 10,000km (approx 6200 miles) or every 12 months Other grease points: Grease every 20,000km (approx 12,400 miles) or every 24 months (2 years)

ZXR750 J race brakes

Brakes ‘n wheels Front brakes: Twin (dual) discs with 4 pot calipers (4 pistons per caliper) Front disc part numbers: EBC MD4022LS and MD4022RS Front brake pad part numbers: EBC FA158 Rear brake: Single disc with 2 pot caliper (2 pistons) Rear disc part number: MD4013 Rear brake pads part number: FA161 Brake systems: Front and rear hydraulic brakes Front tire size: 120/70-17 (3 spoke wheel) Rear tire size: 180/55-17 (3 spoke wheel)

ZXR750 J Carbs

Suspension stuff…. Front suspension: 43mm USD (upside down) Telescopic Forks Front fork oil: 445ml of 5w (light weight) fork oil per fork Rear suspension: Unitrack Monoshock

Weights ‘n measures Dry weight: 195kg (dry weight) Wheelbase: 1420mm Fuel tank capacity: 18 liters Fuel type: Unleaded petrol

Electrics ‘n stuff Ignition system: Electronic CDI Electrical system: 12 volts Battery: YTX12-BS / CTX12-BS Spark plugs: NGK CR9E

Other stuff……. Starter: Electric starter motor Clutch: Hydraulic operated clutch (no cable)

1991 ZXR 750 J1

Useless stuff……. Launched in 1991 the Kawasaki ZXR750 J was based on the 1989 to 1990 ZXR 750 H1 and H2 race replica supersports bikes and there are still plenty of these beasties around today. The ZXR750 was a good bike in it’s day and was used for some racing series and although the ZXR out handled rivals like the GSXR750 and 1100 it was blown away a few years later (along with the FZR’s and GSXR’s) by the Honda Fireblade.

The ZXR750 J was restricted to 100bhp due to an upcoming European 100bhp ban supposedly coming to Europe around the time the J model was launched, but, as with most European laws the BHP ban was scrapped and never came into force. Although the J model had less BHP then the earlier H models (107bhp) and the later K models (121bhp), the J model had good mid range power due to the lower brake horse power!

Although the ZXR750 J model was based on the earlier H1 and H2 models, unfortunately there aren’t many parts that are interchangeable between the 2 bikes as there were numerous changes between the H and J models (including different forks, engine and bodywork).

Buying advice……. There are a fair few of these bikes around and you can pick up a good example with MOT for under £1000 privately. Because of the racing history behind these bikes there are LOADS of ex-racers around (and racing mods like Harrison Billet 6 race calipers can be picked up for these bikes as well!). These bikes were built to take a knock on the track (with beefed up yokes and spindles etc) so lightly crashed bikes can often easily be repaired. Obviously, the youngest of these beasts will be around 20 years old now so the bikes do look a bit ‘long in the tooth’ and will have a few age related gremlins and they DON’T handle like more modern counterparts……. Parts to watch out for when buying….. Only parts to really check on the ZXR750 is the electrics (alternator, CDI etc) as these can be difficult to source. The radiators, which due to the racing design of the rad (curved) alot of the ZXR750 radiators were used on other racing bikes and good examples are difficult to get hold of now! And the upside down forks…. Unfortunately, upside down forks don’t fair well in the UK weather and, unless they’ve been rebuilt and the stanchions replaced they are likely to need work and parts.

Performance mods……. Apart from the usual Dynojet and K and N filter type stuff there is a relatively simple engine mod if you want a bit more from your ZXR750. If you put ZX7 pistons in a ZXR750 (it will need a rebore though as of ZX7′s are a couple of mm’s bigger bore) will increase the CC to around 790cc. Source whitedogbikes.com

The Kawasaki ZXR750 was perhaps the most brutal, most mental of all the Japanese 750s ever. While the bike was launched way back in 1989, its blue/green/white color scheme and hoover-tube air-intakes are instantly recognizable icons in the world of high-performance motorcycling even now. There was about 100 horsepower on tap. Top speed was around 250km/h. And the chassis/suspension combo was tuned with single-minded focus – to get you around corners as fast as possible.

The ZXR750 was replaced by the ZX-7R (and the more race-oriented ZX-7RR) in 1993, and these bikes remained in production till 2003. The ZX-7RR was raced successfully by riders like Scott Russell and Doug Chandler, whose combined efforts resulted in four AMA championships for Kawasaki, over a period of seven years. Russell also took the 7RR to World Superbikes, where he won the 1993 WSB championship.

The ZXR750 and the ZX-7R were significant superbikes of their time and kept Honda VFRs, Suzuki GSX-Rs and Yamaha YZFs on their toes! Source

Make Model	Kawasaki ZX-R 750-J
Year	1991
Engine Type	Four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.
Displacement	749 cc / 45.7 cu-in
Bore X Stroke	71 x 47.3 mm
Cooling System	Liquid cooled
Compression	10.8:1
Lubrication	Wet sump
Engine Oil	10W/40
Induction	4x 38 mm Keihin CVKD (Constant Velocity) carburettors / Ram Air System (single intake)
Ignition	Digital
Spark Plug	NGK, CR9E
Starting	Electric
Max Power	100 hp / 74 kW @ 10500 rpm
Max Power Rear Tire	92.8 hp / 69.2 kW @ 10700 rpm
Max Torque	7.45 kgf-m / 53.8 lb-ft @ 9000rpm
Clutch	Multi plate wet (oil submerged) hydraulic ‘slipper’ clutch
Transmission	6 Speed
Final Drive	Chain
Frame	Aluminum perimeter
Front Suspension	43mm Upside-down forks, adjustable ride height, 13-way rebound
Front Wheel Travel	120 mm / 4.7 in
Rear Suspension	Uni Track monoshock. adjustable ride height, preload, 4-way rebound
Rear Wheel Travel	120 mm / 4.7 in
Front Brakes	2x 320mm discs 4 piston calipers
Rear Brakes	Single 230mm disc 2 piston caliper
Front Tire	120/70ZR17 /Std Pressure 36psi
Rear Tire	180/55ZR17 /Std Pressure 41psi
Rake	24.5°
Trail	95mm / 3.74 in
Wheelbase	1420 mm / 55.9 in
Dry Weight	195 kg / 420.9 lbs
Wet Weight	221.6 kg / 487.2 lbs
Fuel Capacity	18 Liters / 4.7 US gal
Consumption Average	16.3 km/l
Braking 60 - 0 / 100 - 0	13.3m / 37.1m
Standing ¼ Mile	11,2 sec / 196.2 km/h
Top Speed	241 km/h / 149.7 mph

External Links

• http://www.fasterandfaster.net/2014/06/ss-xr1200rr-sportster-is-simply-magical.html