Design life expectancy of a Kz

How long were these meant to last for?

I know kawasaki built a 25 years parts availability into the older models, I guess even in the 70's they had accelerated wear testing, I wonder if they had an age or mileage design life?

Earlier today I was chatting with a zx10 owner, a right headbanger that rides the wheels off it. 65k miles and the clutch basket shattered, presumably metal fatigue. I predict as these get older the failure modes will be well out the usual wear and tear parts replacement. 30-40 years later we are testing these to destruction - literally.

As the Tyrell Corp replicants in' Bladerunne'r film, the D5 combat models didn't last too long. But with kawasaki, the air cooled 8 valve fours and the 'unfashionable' 90's hyper sports water cooled stuff is still going strong.

Maybe if kawasaki made the kz not quite so durable they would have been cheaper and up there with Honda in the sales figures? Discuss

1979 750 twin: I have 85k miles on the entire original bottom end of the engine, did rebore at about 75k. Clutch basket is original as is starter clutch. And that is driving only the hardest stop/go city driving for entire life.

Id be willing to bet that youll see a whole lot more 30 plus year old air cooled kz's on the road than youll ever see of 20 year sport bikes on the road.

I don't know what they planned on or expected, but Ihave a higher mileage KZ1000 that I put on 80,000 miles in 7yrs, and a KZ650 with 168,000 miles on it. As much as I cherish and enjoy the KZ, times are better now in motorcycles. I enjoy my newer motorcycles without frequently having to work. I didn't realize how much work these 70s designs were until I retired my old bikes and went into the 2000s.

I wonder though in 35 - 40 years how many bikes from the early 2000's will still be on the road. By then, some of the electronics stuff may be extremely difficult or impossible to replace. I've already found that to be the case for some electronic type parts for my cars, and the cars (1997, and 1989) are no where near as old as my 1977 bike. Ed

The Japs were still trying to prove they can build quality in the 70's. Honda was building the best in class bikes and remember the CVCC? Those engines met the predicted emission standards for two decades ahead. Kawasaki overbuilt the 900 to outlast and perform the Honda CB 750. Datsun and Toyota, not to mention Isusu, built cars and trucks that put GM, AMC and Ford to shame. When I bought my Z1, my family tried to get me to buy a Luv truck or Courier. At 21 I knew they were junk. I still have my 69 Ford F 250. I doubt you'l see any 2000 model of any kind on the road 30 years from now. :whistle:
Steve

How long will they last? Out performing a CB750 was not all that hard to do. All you needed was a Kawasaki or Yamaha 350. As for the Z1900 I'm quite sure one of these will outlast a certain same period American built iron with out too much trouble.

That's right, coupled with the fact all parts are replaceable. Cam bearings are a good example. Too bad the smaller fours don't have them. The Honda's didn't as well as the GS series.
Steve

I wonder if they ever thought about “design life” back in the 70s and earlier. Years ago I read a short biography of Soichiro Honda who put motors in bicycles in the late 40s and then went on to build complete small step through motorcycles. At some point early on he found his own company’s quality control pretty bad such that about 50% of some of the important components of his engines (cranks or con rods – can’t remember which exactly) would fail QC if tested. He realised that good QC meant good reliability which meant good reputation and in turn good sales. This was at a time when the term “made in Japan” was synonymous with poor quality much like the term “made in China” is today. Meanwhile others in the Japanese manufacturing environment were coming to the same conclusion.

By the time the 60s and 70 came around the Japanese motorcycle manufacturers had quality and reliability down pat and I think it could be argued that these attributes were in a large part responsible for the destruction of the British motorcycle industry. Triumph survived but BSA, Ariel, Norton and others didn’t. Most of the smaller Japanese motorcycles did not survive and we see only the occasional KZ200 here but the larger capacity machines did. Perhaps they were looked after and maintained better but I tend to think this is due more too good manufacturing and good quality control rather than a deliberate attempt to design in longevity.

Will newer motorcycle survive? I can’t see sports bikes which are designed to run at very high RPM lasting the same way. I agree with RonKZ650 that newer bikes are much improved. They handle better, have antilock brakes, traction control and riding style mode at the touch of a button making them safer, sportier and more fun but I keep thinking that the complexity which makes them what they are will shorten their lifespan. I know it’s not a great comparison but consider domestic appliances. Once manufacturers started putting little computers with touchpads bells and whistles and LED displays in these things the life expectancy went way down. They look great but don’t last as I have found to my cost over the past few years.

Whatever they did back in the 70s whether long life was intended or incidental they sure did it right. My own humble KZ750 amazes me when it fires up every Spring and I intend to keep it going until no longer able or until it self-destructs, whichever comes first

I think a modern bike will run for 80 to 100k miles if given the factory recommended service. I've seen a cbr 900 with over 150k on the odometer. Modern bikes don't die from mechanical fault, they die from being wrecked. When I was a Kawasaki tech, I put 6 zx11's into service and the longest running one was totaled with just 1900 miles. The one with the least miles was totaled with 63 miles on it. If you combine a stupid untrained drunk rider with a high performance motorcycle it gets ugly quick.

Since the OP wanted to stay with air cooled I will not mention Councours Owners Group has mileage awards. (miles not kilometers) First is 50K, second 100K 3rd, 150K, 4th 200K 5th 250K and finally 300K. And yes there are C10's running around with 300K. Not many but a few. With regular maintenance the C10 seems to run forever for the most part. My own 09 C14 is approaching 50K of pretty much trouble free ownership with the exception of the battery and a final drive leak which was replaced/repaired under warranty. Also the Concours 14 come with a three year factory warranty with unlimited mileage. Not many air cooled motorcycles of any manuf. come with that long of a warranty.

As for my own Z1B, I Would have never opened up the motor if it had nort been for some bent valves.

12:46AM, back from Grants Pass Or. Maintenance is key. Kawasaki Heavy Industries built ships as well as other large things. They made the best planes, ships and weapons during the war. It's no wonder they put out the machines they did and do today.
Steve