Make Model	Kawasaki ZX-R 750-H2
Year	1990
Engine	Liquid cooled, four stroke, transverse four cylinder, DOHC, 4 valves per cylinder.
Capacity	749
Bore x Stroke	68 x 51.5 mm
Compression Ratio	10.8:1
Induction	4x 36mm  Keihin CVKD
Ignition  /  Starting	Digital  /  electric
Max Power	107 hp 78 kW @ 10500 rpm  (rear tyre 92.8 hp @ 10700 rpm)
Max Torque	6.76Kgm @ 9000rpm
Transmission  /  Drive	6 Speed  /  chain
Front Suspension	43mm Telescopic forks.  adjustable preload and 12-way rebound damping, 120mm wheel travel.
Rear Suspension	Uni Track monoshock.  adjustable preload and 4-way rebound damping, 140mm wheel travel.
Front Brakes	2x 310mm discs 4 piston calipers
Rear Brakes	Single 230mm disc 2 piston caliper
Front Tyre	120/70 ZR17
Rear Tyre	170/60 ZR17
Dry-Weight / Wet-Weight	205 kg  / 226 kg
Fuel Capacity	18 Litres
Consumption  average	17.6 km/lit
Braking 60 - 0 / 100 - 0	13.3 m / 37.5 m
Standing ¼ Mile	10.9 sec  / 201.3 km/h
Top Speed	245.7 km/h

 

The Kawasaki ZXR750: In squidgy little writing for those who can be bothered. The ZXR kind of evolved from the rubbery, bendy Kawasaki GPX750 - the first incarnation, the H1 was ergonomically best suited to strange shaped riders with short legs and very long arms, but introduced that very fashionable, though largely useless detail, the Hoover air pipes. It can be recognised by its more angular look and the strange, limping movement of anyone foolish enough to ride one regularly. It also began the ZXR's fearsome reputatation as a rock solid, rear ended thing, with a gonad mashing tank. The H2 was virtually the same but with a tweaked motor. Both were touted as an RC30 rival at half the price, neither really quite came up with the goods. I crashed one in the Finchley Road. Still, the Hs looked good and were the start of my soft spot for Kwacker 750s.

Next off the production line was the ZXR750J1, which is the model I own. In an effort to keep faith with the traditional ZXR fan, the Hoover pipes remained and the suspension was just as ball bogglingly hard. Where the J really scored though was in being incredibly beautiful, especially in the plain metallic blue colour way and having the best front end in modern motorcycling. I fell desperately in love, especially when Kawasaki gave us one for a year... The other negative point was that the ZXR had a Euro-standard 100bhp motor - slower than the H2 but with good mid-range power. Oh, on early ones, the exhaust system cracks just in front of the collector box.

The J1 was astonishingly enough followed by the J2 - the same bike but with a softer spring in an attempt to sort the ride quality. It still looked beautiful of course, but its days were numbered as the L1 was lurking on the drawing board. Just to digress, at the same time as the standard version with its CV carbs, Kawasaki also sold a single seat, homologation special with close ratio box, alloy tank, wapping great flat slide carbs and slightly more adjustable suspension. The fork diameter was down from 43mm to 41mm allegedly to reduce weight and stiction. The RR was the basis for the highly successful WSB race bikes, but a bit of a pig on the road, not least because you could do around 70mph in first gear... Still, the different cams and pistons (higher compression) made it snot fast at the top end, even if the smooth bores needed more sensitive handling to avoid bogging the motor. I once rode a 125bhp (rear wheel figure) ZXR750K on the road and it was insanely quick. The R's suspension is always reckoned to be slightly better than the standard road bike's, though contrary to what some might tell you, the rear linkage is the same part number...

With the arrival of the L1, it was goodbye to the Hoover pipes and hello to Ram Air. Unfortunately it was also hello to more weight as they had to reinforce the frame to compensate for the big holes they made in it for the air ducts and hello to slower steering geometry. No L I rode ever had the gorgeous roll in cornering and steering characteristics of the earlier ZXR and the motor was much peakier, though top end was now much more impressive. The suspension, fork diameter down to 41mm, was much softer due to a revised linkage and shock, but in my opinion at least the thing felt heavier and just didn't handle with the precision of the J. The L sort of turned into the M and carried on pretty much unchanged until last year when the ZX-7 was introduced

Source nozzer.demon.co.uk

Performance Bike 1990

A GSX-R with a noisy pipe flew past between me and the armco. I was doing about 90 in the fast lane and he came by so fast and so close it made me jump. There was only one thing for it. The workman's bottom that was riding the R was rapidly getting smaller. I stamped down two gears (essential for any acceleration at all) and sunk the rev counter into the red. That was more like it, but by now the R was nearly out of sight. The ZXR's engine note had changed altogether. Gone was the whistle of straight cut gears, and now my Arai was filled with the sound of induction growl and manic engine revs. Between 10 and 12,000 rpm the engine was finally smooth and on-song, and the riding position was finally working as the wind pressure took the weight off my wrists.

The dual carriageway turned into comers that warranted chevrons, but the ZXR, needle nudging 150, sliced through them with pinpoint accuracy. It reeled the GSX-R in as if it had engaged reverse.
A wave of guilt engulfed me as I flashed by the GSX-R, but it proved the ZXR could be good; very good... but worse than its competition until it was travelling in excess of 120mph. Yep, the sort of behaviour that'll finish motorcycling for good and this is the bike that encourages you to commit the crimes.

I want to like the ZXR. Anything that looks so good on paper and in the flesh has to be some use. Pity it's not.
Why not? Well, apart from overdamped and oversprung suspension, the ZXR is a victim of its own styling. If you want a race track refugee, there's a price to be paid. The long stretch over the high and wide tank to the clip-on handlebars puts the rider's weight in two places: the wrists and crotch. Try riding over a few manhole covers and it hurts. It's a 90mph riding position and anything less is literally a pain. Worse, below 90mph (6,500rpm) the engine is harsh, transmitting vibes through the bars. There's not much stomp below 6,500rpm either so a constantly active left foot is needed if you want 750ccs-worth of acceleration.

The motor and suspension tell you 'faster, faster' while your conscience reminds you about your licence. You just can't ride it slowly because it feels horrible, rough, harsh, uncomfortable and gutless. I wonder if that would stand up in court?

The ZXR is crying out for better suspension and the ZZ-R1100's engine. Then it would make sense. The frame and weight distribution can take another 30bhp because they keep the ZXR together at twice the national speed limit. Long sweeping corners are its forte, but tight, twisting switchbacks aren't a problem either. It's not the fastest steering superbike, but use a lot of body English and it does as it's told. Stable is the key word in the ZXR's vocabulary.

Compared to the slim GSX-R, the ZXR feels like riding a sheet of 8 x 4 hardboard: big, top heavy, wide and long. But bumbling around in traffic the size is soon forgotten — it's very manageable, and those short in the leg department will be pleased to know the seat is low.
The Kawasaki is awesome on the brakes, but difficult to turn in or change line. It's the most demanding to ride fast, because its power is between 10 and 12,000rpm (indicated revs).

The softest rear damping still has the back end chattering under power as the rear tyre fights for traction. There's not enough adjustment. Even on the softest setting it's slightly too hard two-up. If you're over 20 stone it should be about right. We recommend that all ZXR750 owners either buy a decent back shock or indulge in a crash course of fish and chips and Boddingtons until the standard unit starts to work as it should.

The clutch feels dead and is noticeable two-up when smooth, quick gear changes are essential to avoid accidents. It's as if the clutch lever is a couple of seconds behind the plates' action. We also had a spot of bother with the clutch after three standing quarters. Fifty quid's-worth of new plates were the only remedy. The gear box is clunky but always accurate, the headlights have been designed by someone who rides at night, and the mirrors by someone who does a lot of serious speeding.

The ZXR's also economical, although that won't be on the top of the shopping list for anyone buying a race replica. On bumble mode 50mpg wasn't out of the question.
The whole bike smacks of quality. The fairing and tank have a paint finish that looks a foot thick. Perhaps more importantly is the ease it comes apart and goes back again. You only
have to try dismantling a Honda to see the difference in workshop time. When it comes to servicing, the Kawasaki will be cheap because it's so much more accessible.

The stock tyres on the ZXR won't last very long. The compound is very soft and sticky. Still, you can't have long life and high grip I suppose.

I'm sure people will buy the ZXR on account of its looks, but if a race replica is what you want buy a GSX-R750L: at least it's a race replica that wins races.

Mark Forsyth

Source PERFORMANCE BIKES 1990