I have owned a Kawasaki Z750 for six years and 32000 miles. It is a '78 bike that was only three years and 9000 miles old when I bought it. The previous owner had it from new and used it only in the summer. Because it wouldn't start I only paid £100. After much head scratching, swearing and connection to a car battery, it finally fired up. The bike needs precise setting of the choke, depending on the weather and warmth of the engine. It wouldn't start because this delicate balance had been upset by rusted silencers. I bought a set from the breakers and starting was immensely improved, though still difficult.
The engine takes a long time to warm up from cold (as much as 15 minutes on very cold days) - shutting off the choke too soon stalls the engine. There's also a great deal of racket from the engine, a DOHC vertical twin with chain driven balance shafts. It becomes quieter as it settles down. Once warm, it neither responds very well to the throttle nor accelerates rapidly - it is probably the slowest 750 on the road. But it does have some stomp once 2000rpm is passed and can hold these revs in fifth gear come any hill or head wind. If you can take a laid back attitude then the Kawa will purr along quite happily. Try pressing the bike beyond the legal limit and the counterbalancers appear to have no effect on vibration, the same graunching, shaking, almost hallucinatory vibes present in a Bonnie will make an appearance.
The Z750 will shake all the way up to 110mph, but past 80mph there are no smooth spots to be found, the vibration just gets worse as speeds increase. Where the Kawasaki differs from the Triumph is that bits chassis don't drop off and it doesn't need regular maintenance or leak oil. Although the bike will cruise at 90mph without any detrimental effect to the engine, the rider's fingers, feet and fillings soon start to complain. After one particularly fast ride in the company of some bigger fours my right hand still couldn't hold a cup of coffee steady an hour later. Despite this, or perhaps perversely because of it, I do enjoy riding the bike fast. The bike has a nice solid feel to it - which considering it weighs over 500lbs with a full tank of petrol it damn well ought to feel solid. The design of the engine doubtless contributes to this excess mass, but it is that very build quality that assures the unusual vertical twin reliability. Like the Yam XS650 twin, Benelli 650 and Laverda 750, all way overweight when compared to the British designs, the Kawa can be ignored for long periods of time but pays the price in carrying as much mass as a similar size four, losing most, but not quite all of the advantages of the vertical twin concept.
The Kawasaki is still much easier to work on, cheaper to buy and has more low down stomp than rival fours. In certain circles this will mean absolutely nothing, but I use this bike all the year around on a minimal budget (by far my largest expenses are tax and insurance I feel greatly cheated to know insurance costs the same as a GPz900). Unfortunately, the concept of economy is somewhat stretched by the fuel consumption and the way the bike eats chains and tyres. The best consumption I've managed has been 52mpg, but I usually average only 34mpg and I've gone as low as 26mpg. The blame, I guess, lies in those balance weights and the sheer mass of the machine. Chains last only 5000 miles and I have to buy a new set of tyres every 8000 miles. Help!
The handling is very dependant on choice of rubber - Roadrunners make it very twitchy, Dunlops are better but still not perfect, while Michelins are fine except over white lines on wet roads. The Z750 is endowed with a degree of feel so it rarely lets the tyre slip away without warning, and, anyway, the kind of power it dumps on the back tyres is so mild that the chassis (which looks like it's derived from the ill handling Z900) is never really bothered.
Where the bike is let down is in choice of geometry and durability of suspension. The former is apparently chosen to make the bike easy to chuck though traffic and lets the bike weave at 80mph plus speeds, while the latter is the kind of junk that packs up as soon as the warranty expires (back in those days a mere six months). Nevertheless, despite the need for plenty of muscle through S bends, it never actually turns really dangerous.
The frame is a fairly typical steel tube duplex item, the steering head benefiting from some useful triangulation of three tubes and the swinging arm mounts having plenty of support. The swinging arm bushes are the usual Jap crap material and need replacing every 10000 miles. The main problem with the frame is merely cosmetic, the lack of primer allows it to go rusty at the mere hint of rain, while the multitude of badly welded seams makes it difficult to clean up properly to apply a decent coat of paint. If I had the energy, I'd strip everything off and get the frame blasted and nylon coated; but that'll have to wait until the engine fails.
The rear shocks were dumped at the earliest opportunity, replaced with Girlings (which made little difference) and then a set of Konis (which are OK but didn't transform the bike). The front forks lack damping and I think the springs should be pensioned off, but, again, I can't really get into the idea of stripping down the forks yet. Pouring in heavy weight oil makes not one iota of difference because the fork seals are shot, the oil just leaks out. The effect on handling isn't so bad as you'd expect, given Kawa's rep with the wild old triples and early fours.
Yes, a Bonnie will leave it standing through the curves, but with a little forethought it will burn off an XS650 and even surprise some fours in the lower speed ranges. It's never made a speed wobble and I've never fallen off, which seems to put it several places ahead of any number of bikes reviewed in the UMG, or perhaps I just don't try hard enough...
The basic cylinder head design bears a passing resemblance to that of the Z900 and is equally trouble free. It's a bit noisy, but the valves still aren't out of the clearance limits yet. The camchain also sounds like it's about due for replacement. The carbs don't go out of balance rapidly, every 10000 miles or so I play around with the settings, but I'm not so sure that this improves things. The engine burns no oil and needs no tops ups between 1500 mile oil changes. Neither the alternator nor rectifier have ever given problems. The electric start whirls and clatters but still works; firing from cold on the kickstart needs six or seven fairly vicious kicks. Batteries do suffer and last for just one year. All the engine castings go white and take hours to clean after just one ride in the wet - in the end I just gave up, finding out it didn't get much worse.
Fitting Universal silencers makes the engine almost impossible to start unless you radically alter the CV carbs, which is about as easy as finding the first issue of the UMG. The tank and side panels still come up nice with application of a bit of T-Cut. The seat, bars and footrests are all very comfortable up to 70mph, but induce arm strain above that speed, which with the vibes leaves the rider rather tired after as little as 30 minutes at 80mph. The front brake doesn't like water and as the rear is also a single disc (I'm still waiting for a company to produce twin rear discs...) the whole feel of riding in the wet can become fear inspiring. Pads last as much as 10000 miles, but the calipers become corroded in half that mileage, either jamming on or just refusing to work. Discs are needed with this kind of mass. The one advantage of the mass is that pillions make no difference to either go or handling - and no-one's complained about the seat.
I suppose I could easily dismiss the Z750 as having the practical performance of a good 400 twin with the running costs of a big four. But it did only cost a hundred notes, doesn't give me much trouble, looks kind of ritzy and thumps along quite happily at the moderate speeds allowed by the police. I did think about fitting an XS650 engine into the chassis, as I'll concede that it's a nicer motor, but I guess I'll just stick with the Kawa, I reckon it'll do at least fifty grand.
Brian Harris