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 to the UK. I've never ridden one of those...
My own Kawasaki ZXR750-J1
is, of course, utterly brilliant, beautiful and snot quick, else I
wouldn't own it - if you happen to be American it's a 1991/2 ZX-7R.
It's a bike which in stock form is let down by overhard rear
suspension, a tank that poses a serious threat to your reproductive
abilities on its own and, which in tandem with the suspension makes
the ZXR the nearest thing to a free vasectomy currently available.
The other snag is the relatively feeble top end power, the nearest
thing to a psychic vasectomy for us macho ZXR race wannabes.
If it looks kind of familiar (if there were a photo here it might) then that's because it was a SuperBike long term test / project and popped up in the mag from time to time. It was also on our stand at the NEC Bike Show about four years ago. When I left the mag, I slipped the ZXR into a Sainsbury carrier and we sneaked out of sordid Croydon together to start a new life among the dark Satanic mills.
Fortunately the basics of the bike were
always right - rock solid alloy beam frame, quickish steering and a
fabulous front end - it's a hard sensation to describe, but it's
almost as if the bike hungers for the bends, it just wants to get
cranked over and over and over. Even better the J weighs less than
its porky successor the L. Even more fortuitously, most of the faults
are correctable, though it helps if you happen to work for a
motorcycle magazine ...
The MotorFor reasons best known to Kawasaki, the J came as standard with a cruddy motor producing only 100bhp (claimed) at the crank. This, it goes without saying, was not good enough for us rufty tufty bikers (no relation to Tufty the Squirrel, remember him? On a Dynojet rolling road dynometer this translated to about 92bhp. To rub salt into the wounds, Kawasaki also produced an RR homologation special version - the ZXR750K with different cams, higher compression pistons, gearbox and flatslide carbs. The K produced around 103bhp on the dyno, but was a bit too uncompromising for the road.
However, riding one - a future Phase One Endurance race bike, the first K in the UK - saw the genesis of a fiendishly cunning plan. Why not install the pistons and cams from the K version into the J and see what happened? The mildly disappointing result was an improvement in top end power, but losses low down and in the mid-range where the J was impressive as stock. Not so great I thought.
In fact, when the L was released two years later, it used basically the same cam timing and produced a very similar peaky power curve. First improvement was to fit an adjustable Simms and Rohm ignition advancer, which filled in some of the dips in the power curve. A Stage One Dynojet kit had already been fitted (for more information and a technical query service follow the link) which improved throttle response, but the motor was otherwise stock.
At this stage the engine felt half finished - it was peaky and on the road the extra 8bhp or so at the peak was cancelled out by the drop in mid-range power. A mere 140mph or so was simply not good enough, so the bike was dispatched to tuning guru and all round good egg Jez Lloyd at Track Record in Camberley for some optimisation.(Rather unfortunately I agreed to dub Jez 'God" in print if the motor delivered the berries. It did. I did. To this day I live in terror of a visit from a particularly savage Carmelite order of outraged motorcycling nuns).
Using adjustable cam sprockets supplied by Richard Alban of TTS (another fine chap), Track Record set up the cam timing very carefully to maximise mid-range pull - ZXRs are very sensitive to cam timing and getting it wrong by a few degrees either way can wreck the power curve. It's a bit like boiling an egg, easy to get horribly wrong. This was also important as the head went off to the very cheerful (ahem) George of Mez Porting to be skimmed to give about 12:1 compression, which alters the cam timing, and the inlet ports were remodelled to quasi-RC30 spec. Mez also filled out the cavernous inlet tracts to improve low speed response. 'What you mean this is a road bike? This is a race bike. You must race it. I don't waste my time on no poxy road bike etc.' I kind of figure if George ever reads this he'll be after me too.
As a final touch a Canadian Hindle exhaust was fitted along with carbon fibre 'stealth' silencer and the bike was set up by Larry Webb of PDQ in Taplow. You can see the results on the dyno chart (or you'll be able to when I've inserted it...)
Top end is now about 109bhp with 110bhp on
all gear runs which simulate maximum acceleration through the gears,
throttle response is much quicker than standard with a crisp, hard
sort of feel to it, but best of all, the mid-range is hugely
improved, to the extent that the bike is now producing more power and
torque than one of Jez's vaunted tuned RC30s right through the
mid-range. On the road it's brilliant apart from a mild flatspot
between 3,000 and 4,000 revs which I'm trying to sort out. It drinks
super unleaded or four star petrol, makes interesting snarling noises
and even geared up, pulls really strongly from around 4,000 revs. I
am an ecstatically happy rapido bunny, though ear plugs come in
useful at speed.
The ChassisIs generally brilliant, well apart from that rear end... It's now generally agreed that Kawasaki got things horribly wrong with the shock, overspring and overdamped. There are two solutions: fit a new shock recalibrated to suit the existing wheel / shock ratio or change the ratio by fitting a new rocker arm in the linkage.
The problem with the latter solution is that even with the ride height adjuster set at maximum, using an NWS linkage or the later 'L' version means that ride height is reduced, ground clearance goes down and the steering is slowed ruining the precise steering response of the bike (later versions had slower geometry as well as weighing more). One solution to this would be to fit an aftermarket shock with a longer than standard body to compensate I guess.
The solution I opted for was a completely new shock from TT-race shock set-up super guru and very nice quietly spoken chap, Ron Williams of Maxton. The Maxton Koni is based on a car Formula One race damper and works stunningly well. The rear end's still taut, but there's none of the gonad-mashing wallops every time you hit a bump at speed. Brilliant and the steering remains the same. A cheaper option is to get Maxton to rebuild your stock shock to a softer spec.
Ron also revalved the forks - the springs are the right rating he says - to improve damping and adjustability. The combination of a Maxton front and rear is light years better than the standard set up. It sits on the road really well, corners like a, errrr, something that corners very well and is superb. It also pulls stonking stoppies.
Bits And BobsThe original metallic blue paintwork was beautiful, with a sort of restrained elegance that the Japanese seem to have jetisoned in favour of vile, multi-coloured visual puke graphics, but it was tempting ot get something a bit out of the ordinary - still restrained but different. So the whole thing is finished off by Simon Templeman of Art Asylum's brilliant two-tone metallic red paint job which changes colour according to the light. (There really ought to be a piccy here, one day there will be). There are Fred Gasit murals on either side of the front mudguard too - stoppy one side, wheelie the other.
NWS provided the neat carbon - kevlar frame guards and inspired alloy rear-set footrests - these are further back than the stock items, but still comfortable enough for everyday use - and I can also thoroughly endorse their brilliant one-man-operated Pro Stand which locates in the swinging arm pivot and can be operated by - you guessed it - one man.
The Hindle pipe is excellent in terms of power but is rusting badly - at this point the downpipes were mild steel, the latest versions are supposed to be stainless - it also cuts 12lb or so from the weight of the bike, which is a good thing.
Brakes And Tyres
The standard brakes are pretty damn good in my experience and I tend to stick to the OE pads, even though they're a bit pricey. New front discs were fitted after the originals warped at about 15,000 miles, but this followed on from a particularly frenzied track session so probably isn't typical.
Goodridge stainless steel braided brake lines firm up the lever feel and look good, but are, in my opinion anyway, a luzury rather than a necessity - the standard brakes work pretty good.
Finally, the bike usually wears Pirelli Dragons in standard sizes. Good grip, reasonable wear and a very nice feel to the steering.
Next StepsWell, a set of Marchesinis or similarly trick mag wheels would be nice, but I'm wary of losing some of the high speed stability by reducing the gyroscopic effect. Similarly it would be interesting to try and fit a home-brewed ram air system, but I'm not sure I can be bothered with the inevitable carburation hassles.
More prosaically I may well try different sized jets in the inner and outer cylinders as fitted by the factory, though again I'm not convinced that it'll be worth the inevitable faff. Of course what I ought to do is reverse the hoses on the truly awful and potentially lethal reserve tap, but somehow I never seem to get round to it.
Really I'm happy enough as things stand. It's comfy enough for long blasts, well 200 miles or so at least, does a good job of putting off pillions - just as well as they shag the handling and it puts a big stupid grin on my mug, still. Like I said, there's nothing I'd swap it for ...
Sorry folks, I really can't be
bothered to input a spec sheet, I did enough of that when I was at
SuperBike. Did you buggers ever read it? Did you
care if 'four-piston caliper' was hyphenated or not? Did you ever
notice when the gremlins increased fuel capacity to 250 litres? Did
you heck
The AlternativesNever one to miss the chance to give the opposition a good slagging, here's the Nozzer rundown of the main rivals:
FireBlade: Common as
muck, nouveau riche, overly quick steering, twitchy thing. A good
bike but lacks class.
YZF750: Bland motor, no
class, tedious looks and a very nasty feel to the front brake. Lacks
guts.
GSX-R750: Early ones
have psychopathic tendencies and great suspension, later stuff living
on reputation IMHO
Ducatis: Do me a favour
- I like riding bikes, not waiting for them to come back after
warranty work...
RC30: Best thing I ever
rode was a full race RC30 - gimme, gimme, gimme...
VFR750: Nice all rounder
but kind of dull don't ya think?
