Kawasaki Z1 v Honda CB750

Kawasaki Z1 v Honda CB750

Honda CB750 V Kawasaki Z1History tells us that the first machine that we now know as a Superbike was the CB750 and if you look no further in the annals of time than that then all is well. Honda only got there by the skin of their teeth however, as lurking in the wings during the same period was Kawasaki’s much higher specification, 750cc four cylinder machine that unfortunately was being so rigorously developed and tested it missed the limelight by the merest of whiskers.

Once the CB was released the Kawasaki heavy industries team scurried off and re thought their plans. They were not in any hurry however as it took a further three years and many secret meetings with test staff in the US to produce the 900 cc version (code named the New York steak). They had the advantage of now knowing exactly what the opposition had planned and could fine-tune their own thinking to suit and hopefully steal the march on both performance and style. The Kawasaki team certainly did exactly that, if the CB was Honda’s attempt at giving us what they thought we wanted, the Z1 was nothing short of stealing the very dreams and desires from our craniums and turning it to hard, fast metal. The Z1 of 1973 gave the early 70’s man in the street something that no one out side of the MV Agusta race team could ever have experienced, with a genuine 80 plus bhp on tap the big Kwak was as powerful as the top GP racers of the time, the equivalent of having 240 plus bhp on tap now.

Honda CB750 V Kawasaki Z1 TestLittle is known concerning the exact detail of that early machine that was so far into its development stage before being shelved forever but if the Z1 was anything like the 750cc version then I for one think Kawasaki were foolish not to go ahead with the project. For certain it had twin overhead camshafts and was good for well over 60bhp in its early form.

What Kawasaki did do however upon learning of Hondas exploits was to return to the test bench and develop something all together more advanced and tantalising? Gone were the power sapping valve rockers used on the Honda, the Kwak simply used a direct contact between the camshaft and the shim buckets making the valve operation altogether more efficient. Further down in the bilges of the engine the noisy and inefficient primary drive chain on the CB was replaced by a direct gear drive from a crank web, cut as a gear, straight on to the clutch and gear train.

Riding the CB first was without doubt the best way to approach these two machines, on first cocking a leg over and pressing the starter button the first surprise is nothing happens, one has to wait for the engine to whirr away, reaching a certain revolution before it chimes in and off we go. The top end is not rattley but there is some noise evident from the cam cover and when warm the bottom end, with its chain drive between the crank and the gear train, joins in with the percussion section too, adding a syncopated beat to the rhythm of the rockers and cam chain. The CB is heavy but carries the weight well being finely balanced and raring to go, the engine is smooth and the carburetion adequate for most tasks. During steady cornering the big Honda tracks true and securely, but turn the wick slightly and the rear end gets a little soggy, once on the move the rest of the chassis does tend to join in with the dance and you can easily be doing the twist mid bend as the supple steel tubing yields to the road forces. Add a touch of throttle during this process and yet another force begins to act upon the poor old frame and it becomes difficult to hold a consistent line.

Honda CB750 V Kawasaki Z1 Road TestBraking produced nothing shocking at all and even for the period the floating caliper front brake must have been pretty poor and one can only describe the anchors as adequate. All this aside, it is a nice bike and certainly should you have jumped on one in 1969, after a lifetime riding thumping singles and twins it could well have been a revelation. It does lack technical complexity though and would surely have benefited from double overhead camshafts, used by Honda much earlier in the middle weight twins, and a few more go faster goodies dotted around the power plant. It is quite remarkable that they didn’t re design the type well before the end of the seventies as every single oriental bike maker had built far more impressive and more technically advanced 750cc machinery by the mid point of the decade. The overall feeling when riding the CB is one of safe performance and convenience, the Honda is most certainly not a scratchers tool, which once you take away the “Worlds first Superbike” tag surprisingly becomes a little bland. This is a reasonably rapid, if a little docile, large capacity machine that you could live with, trouble free, day after day and back in the late sixties that would have been a real first.

Swapping the sixties CB for the 70’s Z1 couldn’t have been more enlightening, the big Kwak is everything the Honda could have been and then some, with power and torque to spare. The seating position is less cramped than on the Honda and the overall feel is of a big bike underneath you, which you sit in and feel part of rather than perch on top of. Press the starter and the response is instantaneous from the upright bank of cylinders with a lion like road bellowing from those sweeping chrome plated silencers and little I the way of engine noise despite an awful lot of components whirring around inches away from your legs. If the CB engine is smooth the Kwak is some word even silkier still and once on the move those twenty extra gee gees under the tank combine with a similar increase in mid range torque to make themselves known in all the right ways. Let this baby go and the scenery soon gets blurry with impressive acceleration even by today’s high standards and a standing quarter time a whole second faster than anything else from the period.

The Z1 is considerably more nimble too, particularly at low speeds, despite carrying a few extra pounds around the midriff, the taught chassis handles most that is thrown at it and only requires an accurate set up entering into a corner for it to get around without hassle. The power of the four cylinder engine can, and does, get the better of the chassis but this is more likely the fault of the tyres which being the same size as the Hondas are definitely on the skinny side for so many horses and so much all up weight. One can only guess how the Honda frame would handle the power of the Z1 but I can make rub my crystal ball and make a pretty accurate prediction that without major modification and serious updating of components like shock absorbers etc, that it wouldn’t make a very good job of it. Of course some owners would have fitted a steering damper to the Kwak back in the seventies the fittings are provided for this from the outset but in reality little improvement would have been felt as those wide bars can over come most shakes and wobbles from the front end.

As a direct comparison the Z1 is literally years ahead of the CB in both technology and handling, the CB appears to have been made well on the safe side and with little regard shown towards to types sporting potential. This may have been a short-sighted mistake on the part of the design team at big H as they certainly had a few clues being presented to them, via Kawasaki of all people with their two stroke triples, on the way motorcycling was going. The Z1 however hits the nail right on the head and supplies all the sporty biker required back in the seventies. The fact that every other manufacturer followed suit soon after is proof that they were right from the outset.

CB750 v Z1Although conceived at exactly the same time during the late sixties the life of these two machines could not have been more different. The technologically safe Honda remained in production virtually unchanged for a decade becoming in the process one of the best selling machines of all time with around a million falling off the production line and into the showrooms around the world. It spawned a reasonably effective racer too with a factory kit being available, mainly stateside, enabling the CB750R to compete with the Brit triples and Harley twins. The Kawasaki by comparison didn’t have such a lengthy shelf life and made way for allegedly “improved” models after a mere five years. During that time many changes were made including the addition of a second front disc in 1976, while a reduction in carburettor size and smaller exhausts to reduce power and meet ever tightening emission regulations on the other side of the pond. While the CB is now relatively commonplace around the Classic scene the rare, and far more stunning looking, Z1 still turns heads wherever they appear.

Honda CB750 Specifications

  • Engine: Air-cooled four-cylinder inline four stroke. Single overhead camshaft
  • Capacity: 736cc
  • Bore & stroke: 61 x 63mm
  • Compression Ratio: 9.4:1
  • Carburation: 4 x Keihin 28mm butterfly choke
  • Max Power: 67bhp @ 8,000rpm
  • Torque: 44ft-lbs@ 7,000rpm
  • Ignition: contact breakers
  • Transmission: Wet multi plate clutch plate, five speed
  • Frame: Steel tube twin loop
  • Suspension: 35mm telescopic front forks, twin shock rear
  • Wheels: 3.25 x 19 front 4.00 x 18” rear
  • Brakes: 300mm disc Single floating calliper, front. 180mm single leading drum, rear
  • Wheelbase: 1455mm
  • Weight: 480lbs (218 kgs)
  • Fuel capacity: 17 litres inc 5 litre reserve
  • Top speed: 108 mph

Kawasaki Z900 Specifications

  • Engine: air-cooled four cylinder inline four stroke, double overhead camshaft
  • Capacity: 903cc
  • Bore & stroke: 66 x 66mm
  • Compression Ratio: 8.5:1
  • Carburation: 4 x Mikuni 28mm
  • strong>Max Power: 82bhp @ 8,500rpm
  • Torque: 54.3 ft-lbs@ 7,000rpm
  • Ignition: contact breakers
  • Transmission: wet multi plate clutch plate, five speed
  • Frame: Steel tube twin loop
  • Suspension: 35mm telescopic front forks, twin shock rear
  • Wheels: 3.25 x 19 front 4.00 x 18” rear
  • Brakes: 297mm disc Single floating calliper, front, 198mm single leading drum, rear
  • Wheelbase: 1490mm
  • Weight: 506lbs (230 kgs)
  • Fuel capacity: 16 litres (18litres US spec) inc 5 litre reserve
  • Top speed: 120 mph

Kawasaki Z1 v Honda CB750 Gallery

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