Kawasaki Z 650


Make Model

Kawasaki Z 650




Four stroke, transverse four cylinder, DOHC, 2 valves per cylinder


652 cc / 39.7 cu-in
Bore x Stroke 62 х 54 mm
Cooling System Air cooled
Compression Ratio 9.5:1
Lubrication Dry sump
Oil Capacity 7.4 US pint


4x 24mm Mikuni VM24SS carburetors


Battery & coil
Starting Electric & kick

Max Power

66 hp / 48.2 kW @ 8500 rpm

Max Torque

57 Nm / 42 lb-ft @ 7000 rpm
Clutch Wet, multi-plate


5 Speed
Final Drive Chain
Gear Ratio 1st 15.63:1 2nd 10.93:1 3rd 8.52:1 4th 6.97:1 5th 5.97:1
Frame Steel twin loop cradle

Front Suspension

Telescopic hydraulic fork

Rear Suspension

Swinging fork

Front Brakes

Single 275mm disc 1 piston caliper

Rear Brakes

180mm Drum

Front Tyre


Rear Tyre

Rake 27°
Trail 106 mm / 4.2 in
Wheelbase 1437 mm / 56.6 in
Seat Height 800 mm  / 31.5 in
Ground Clearance
152 mm / 6.0 in

Dry Weight

211 kg / 465 lbs
Wet Weight 220 kg / 485 lbs

Fuel Capacity 

16.5 Litres / 4.3 US gal

Consumption Average

16.8 km/lit

Standing ¼ Mile  

13.8 sec

Top Speed

186 km/h / 115.5 mph

1976/1977 Z650-B1

This four-stroke four-cylinder motorcycle boasted double overhead camshafts just like the bigger Z1 and Kawasaki claimed 64 bhp (48 kW) from the 652 cc motor. Unlike the Z1, the 650 used a plain bearing crankshaft with a HyVo multiplate chain primary drive instead of a gear drive. This system necessitated the installation of a third (intermediate) shaft in the transmission to drive the input side of the clutch.
Also included for this model year only was a three phase excited field type alternator. Subsequent years of all models (until 1981) were equipped with a single phase permanent magnet (or shunt type) alternator.

Another departure from the Z1 engine design was the use of a shim-under-bucket method of setting valve clearances. The Z1 engine employed a shim-over-bucket design for this purpose and there had been reports of the camshafts actually forcing the shims in the Z1 engine out of position with consequent damage. Project leader Inamura made sure this would not be a problem with the 650 engine. A single 245 mm disc was used up front with a 250 mm drum on the rear, more than enough to handle this relatively lightweight bike. Both front and rear fenders were chrome.

1977 KZ650-C1

This model was offered only in North America (and possibly Japan). It was named the Z650 Custom and was introduced in early 1977, somewhat later than the B1. The C1 model differed from the B1 model in the following areas: it had cast alloy seven spoke wheels instead of conventional spoked items like the B1; disc brakes both front and rear with dual discs at the front having the calipers mounted behind the fork legs. It had different fork bottoms to cater for the rear mounted calipers. The C1 also sported four-way hazard flashers, which were not fitted to the B1.

Kawasaki's Z650 four has carved itself an businessman spending a day helping his corn-enviable reputation for speed and stamina since panion to hospital after a crash and after side-it appeared in late 1976. Proof of the speed came swiping a kangaroo hard enough for Rich to think at Daytona in the following March when he had broken a leg. The Z650 never missed a beat. Kawasaki attacked the world 750 cc endurance We were not quite so adventurous during our records with a trio of mildly modified Z650 own 600-mile road test but we learned that those roadsters. They came away with a bunch of records were no fluke. Firstly, there is no doubt records that would have been impressive for a that the Z650 is very fast. It can accelerate to 60 1,000 cc roadster, let alone a 650. Best were the mph as quick as anything you can buy on wheels. FIM world 1,000 km at 128-4 mph, the If proof was ever needed that there is only one AM A/FIM six-hour at 127-7 mph and the AMA thing better than a fast big bike, and that's a fast 100-miler at 130 mph. For good measure they small bike, the Z650 is it. rounded off with the world FIM 24-hour record For motor cycles, small is definitely beautiful, at 117-2 mph. Earlier, the American, Rich Willet If there is one thing that hampers the enjoyment attacked the round the coast Australia record on of a bike, it is weight and bulk. The bulkier and his Z650 with a colleague. Just over ten days later heavier a machine the more difficult it is to he was back at Sydney having covered 9,550 manouevre, the more trouble it becomes when miles to beat the record for the toughest trip in cornering and the more fuel it uses, motor cycling by the scant margin of one hour. The Z650 Kawasaki is tangible evidence that This was despite the 44-year old St Louis smaller is better. At 495 lb, it weighs some 30 lb lighter than most of the seven fifties and with a 56.6-in wheelbase is about 3 inches shorter. On the road the bike gives away nothing in performance and is far and away a better performer than 550 cc machines. Flat-out mean top speed at MIRA was 119-6 mph, only 4 mph down on Suzuki's GS750 and 2 mph less than the Honda CB750F1.

Even more stunning is its acceleration. Taking to the test track like a drag racer, the Z650 scorched through the quarter-mile in 12-9 sec with a terminal speed of 101-6 mph. Although eight runs were timed, six of which were 13 sec or under, the bike finished as unruffled as ever.

The secret is not only the power of the twin-cam 652 cc short-stroke, four-cylinder engine, but the bike's perfect gearing and balance. The Z650's wheelbase is neither so short as to provoke unmanageable wheelies on take-off nor so long that there is too much wheelspin.

Drop the clutch at 7,000 rpm and the Kawasaki just digs in and gets on with the job, the front wheel just hovering above the tarmac for the first few yards. It is as though the bike was made for drag racing. The proof of this is that the Z650 is one of the quickest bikes from rest through 110 yards. The terminal speed of 66.8 mph has only been beaten once - by the super-fast 1973 Kawasaki Z1 903 cc four at 68 mph. It can reach 50 mph in just 3 sec from rest.

Yet the bike is no awkward rev-happy racer. Although it can scream up to 10,000 rpm (the red line is at 9,000 rpm), the engine is sweet and flexible enough to haul along at under 4,000 rpm and there is torque enough to give a sizeable kick in the seat as you open up.

Apart from a band around 7,000 rpm, the Z650 is exceptionally smooth for a four in-line, particularly at about 70 mph in top gear (equal to 5,500 rpm.) This makes it very relaxing to ride at speed, particularly as there is hardly a hint of 'cammyness' with ample response throughout the range.

Power characteristics like this usually result in above average fuel economy, but although the six-fifty four could return 52 mpg around town, the overall test figure of 46-5 mpg was lower than expected, but doubtless due to the heavy consumption of 34 mpg during the performance testing. Range on the 3£ gallon fuel tank is between 150 and 160 miles.

Although Kawasaki claim the machine will run on unleaded fuel like the Z1000, in the case of the test bike unless it was run on four-star fuel it would detonate at small throttle openings when pulling hard. This off-idle weakness in the mixture strength was probably connected with the Z650's excessive cold-bloodedness when starting from cold. The process of starting is made more tricky by the need to disengage the clutch when pressing the starter button.

Excellent though the machine is on the track or when ridden hard, the Z650 is not quite so impressive when the going is more relaxed. At low speeds, for example around town streets, the gearchange hangs up and is very clunky, particularly when engaging bottom gear from neutral. On the open road, the gearbox which is identical to the unit on the Z750 twin, is by contrast as slick and crisp as you could want.

Town riding is further spoiled by the excessive backlash in the gearbox, which is compounded by that stuttering in the carburation.

Being much smaller and more compact than the Z1000, the Z650 has none of the bigger model's awe-inspiring bulk, and it is a markedly better handling machine. Although the suspension is softer and more comfortable than the big model one can skim through bends much more confidently than the Z900 or Z1000 would ever allow, and with none of the gut-churning high-speed wobbles that still mark the Z1000 as a bike to be respected when the going gets hot.

The main improvement on the Z650 is a stiffer frame with more sensibly designed steering geometry. The rake of the front fork has been pulled back to 63 degrees, in line with the Z750 twin, and combined with more trail. The bike is very stable in fast bends, while at low speeds there is only the slightest hint of 'oversteer' - that feeling that the bike wants to drop further into a corner - and unlike the Z900 it does not want to straighten up when cranked over in fast corners.

Ground clearance is enhanced by use of one silencer either side and the only limitation on the amount you can crank the bike over is the grip of the Dunlop Gold Seal tyres. If you manage to touch down the left side projection of the main stand you are a long, long way over.

Harder riders will prefer stiffer springs on the Z650, for although it is very much a sporting bike, the suspension has been tailored to have a broader appeal. The 100 lb/in rear springs give a smooth ride and the dampers are fairly well matched - like the front fork.

H owever, there is still some of the vagueness in the overall feel of the machine that puts it not quite on par with the best handling roadsters now available.

Like the GS750 Suzuki, the Z650 has been well planned for the rider. The seat is soft yet secure enough to prevent you moving about, and the footrests are well tucked in.

The lowish handlebar is properly swept back at the right angle and can be adjusted to taste even though the wiring runs neatly through the tubing. Only general criticism of the Z650 is that the shortness of the bike will put off taller riders. Cruising at anything over 70 mph becomes tiresome after only a few minutes due to the height of the handlebar grips.

Along with practically all other Japanese bikes the Z650 has a stainless-steel, front-brake disc which is fine when dry, but always has to be allowed for when wet and cold. Kawasaki sensibly resisted the fashionable temptation to fit another to the rear wheel, and retain a 7-in drum brake. This works admirably, the brakes being neither too grabby nor under-powered.

Electrical equipment, apart from the headlamp, is first class. A high power 280-watt alternator supplies all the needs of the system and the battery never went limp after days of slow commuter riding. Indicators are large and bright. However, the headlamp suffers from being indistinct and lacking in penetration on both dipped and main beam.

The heart of the Z650 is its modern power unit. Quiet and unobtrusive, it whispers along with hardly a rustle from the valve gear or exhaust. At 70 mph in top the engine is barely audible above wind roar. Designed specifically with quietness in mind, it shares more in common with Honda's CB500 four. Unlike the Z1000 with its roller bearing crankshaft and gear primary drive, the Z650 uses a plain bearing crank with a Morse type chain running to a shaft between the crank and the clutch, which is driven by gears. For longevity, the valves are opened by twin-overhead camshafts and bucket followers and although the Kawasaki service book says that valve clearances need checking every 3,000 miles, it is claimed that they will not need attention until four times that distance. That is just as well, for the camshafts need to be lifted to vary the 47p shims under the buckets.

Longer servicing intervals are becoming more and more common; details like the sight window on the engine to check oil level ease the work. The rear chain, although very costly, pays its way by lasting up to 700 miles before needing adjustment thanks to the use of O-rings to keep the oil in the links and the dirt out.

Undoubtedly, the Z650 is the best Kawasaki so far. It restores the image of thundering power and speed with a new one of civilised restraint. The Z650 can afford to be sober in appearance because it takes on the 750s and just about equals them at their own game.

Road Test 1976