Motorcycle minds were blown when the 1973 Kawasaki Z1 debuted with its 903cc engine, double overhead cams and burly styling--and Team Green's four-cylinder superbike was born--in rootbeer brown! Did 40-hp Triumphs ever have a chance? Technical Editor Kevin Cameron and Editor-in-Chief Mark Hoyer talk about the Z1's origins, how it compared to the Honda CB750, and the marketplace the bike entered, including facing off against Kawasaki's own two-stroke triples. The guys wander off a bit on this one and coincidentally heard the same crazy superbike race announcer at Monza more than a decade apart! (Really, it's a cool story.) There's a moment on Harley-Davidson steering philosophy that's at least peripherally related, and a little about the death of the two-stroke, plus so much more. Join us!
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SportsTranscript
00:00:00Welcome to the Cycle World Podcast. We're back. That means it's Wednesday. We do this every Wednesday.
00:00:05We is me, Mark Hoyer, Editor-in-Chief of Cycle World, and Kevin Cameron, our Technical Editor of Some Note.
00:00:12He's read some books, done some things, built some bikes, been paying attention a long time.
00:00:17So, this week, we're attacking, inviting, examining the Kawasaki Z1, the legendary Kawasaki Superbike of 1973.
00:00:33All credit to Honda for coming out with an inline-four, four-cylinder with four pipes in sort of 69,
00:00:39and really changing the marketplace and making affordable things that had not been affordable.
00:00:47And kind of cutting the British industry off at the knees.
00:00:52Well, they did that to themselves. That's a separate program.
00:00:55Yes, it is.
00:00:57Whatever happened to...
00:00:59The British motorcycle industry.
00:01:01Yeah, but at the time, Kawasaki, you know, Kawasaki was working on a 750 itself,
00:01:09and then the Honda came out, and Kawasaki said, oh, wait a minute, let's think about this.
00:01:14And the result was the Z1.
00:01:16And what do you think, Kevin?
00:01:20Well, I think that it's a fascinating era, because what was happening here is that the Japanese had entered the U.S. market with a toe, and then a foot, and then a calf.
00:01:34And they knew that there was a potential for sales of big motorcycles.
00:01:43The market was, what, 60,000 bikes, they figured, at the time.
00:01:48But they'd swashbuckled in and created their own market, and people were saying, well, when they saw the sales figures, they said, that's for a year, right?
00:01:58And they said, no, that is for one month.
00:02:02And so each of these companies made the transition from being a manufacturer of campus cadet little motorbikes to let's go the whole way.
00:02:17Americans want big, fast motorcycles, and we're going to build them.
00:02:21So it was.
00:02:22It was tremendously exciting.
00:02:24And if you were reading the magazines at that time and talking with people, it was grand.
00:02:32And the Triumph Trident had just appeared, and it was puzzling, because it didn't seem to represent market research carried out on Earth, some other planet, possibly.
00:02:48So I think that Kawasaki made a master stroke by making the thing 903ccs and styling it so that it was not too large a jump from a Bonneville, a Triumph Bonneville, to the original Z1.
00:03:15The bulbous tank, which dated back to the 20s, when a deep forming of sheet steel became possible, and the tube frame, the Americans didn't want any of that sheet metal frame stuff.
00:03:31Everybody tried it.
00:03:32It was rejected.
00:03:34And the bike had to have disc brakes because Honda had taken the plunge.
00:03:47Peter Williams had a disc brake on his G50 that was made out of British race car parts.
00:03:55And Honda went ahead with the disc brake on CB750.
00:04:01So a lot of things changed in a very big way.
00:04:05And suddenly, everybody had to have one of these motorcycles.
00:04:11It was just so attractive.
00:04:15And none of us had any idea at the time that the 1,000cc category was just going to grow into a mighty tree.
00:04:26It looked like a promising seedling.
00:04:30Well, little we knew.
00:04:32Really, the beginning of, well, A, the beginning of the term superbike, which showed up in Cycle magazine when they did their big 750 shootout with the Ducati and all those.
00:04:44And then, in rapid fashion, it showed up in Cycle World, like, the next month in their big shootout.
00:04:52And it really launched, did it not launch the performance wars that we enjoy?
00:04:57Well, we enjoyed up until a few years ago.
00:04:59I mean, we're sort of pausing right now for twin-cylinder torque bikes and emissions.
00:05:06And, you know, but it really launched the ship that was last year plus 5% year after year.
00:05:13Like, we're going to lower the quarter-mile time, and we're going to increase the horsepower.
00:05:17And we all were shocked and delighted when 750s made 75 horsepower, and suddenly they were making 105, and away we've gone.
00:05:28And, you know, let's see.
00:05:31I'd say the GSX-R was probably, say, around 2000, a 750 was making 126 horsepower at the rear wheel.
00:05:40Not bad.
00:05:41Not bad.
00:05:41And very trackably and with good mileage.
00:05:44Yeah.
00:05:44But it really started then.
00:05:46And it started with Z1, and it started with CB750, and, you know, Norton Commandos were kind of hanging on for dear life.
00:05:53The 850s were great running bikes, very vigorous and fun to ride, and similar in performance, but sort of, how do you put it?
00:06:05What were they going to do next?
00:06:07Well, yeah.
00:06:07I mean, it's like, I don't know what it is.
00:06:10It's a spaceship.
00:06:11It's not spaceship cladding on a steam engine, but it's sort of like that, right?
00:06:15You know, it's a transmission that was designed in the, when's the AMC box?
00:06:20The AMC box was sort of 40s?
00:06:23Yeah, I expect so.
00:06:24I don't know.
00:06:25I mean, a great shifting gearbox, but they started, I mean, it was the same gearbox that they'd been running on their old 500s and stuff.
00:06:31Yes.
00:06:31But away we went, and Z1 really put a stamp on it, because, you know, the Honda CB750 was a very good performing bike, but I think, you know, you ride one today and you compare it to an 850 Commando.
00:06:48You know, like I rode a beautifully restored CB750, and the Commando actually had a lot more snap and bigger, and the throttle pole was lighter, and it sort of was a more playful feeling.
00:07:03Yeah.
00:07:04But Z1 comes in with a big motor and just says, here's what we got, Honda.
00:07:11Yep.
00:07:13So, it wasn't long before people were trying to race the things, and, of course, that's where the term superbike really found its home.
00:07:28And I was at a race at Monza, and their announcer there was famous for his long cry.
00:07:42He would announce the superbike race by saying, superbike!
00:07:50Dude, that same guy was at Monza in 2000 when I went, and Troy Bayless was taken up to Ducati.
00:07:57Oh, yeah, yeah.
00:07:58The factory team, he was pulled from Vance and Himes, that same guy saying the same thing.
00:08:02And what was great was, because of the chicanes at Monza, you know, it was Pierre Francesco Keeley who won a race, like he was breaking very, very hard, he said.
00:08:12And they're sort of, they're going into the chicanes, and Keeley's trying to go up the inside of somebody, and that announcer would come on and say,
00:08:20Keeley, Keeley, Keeley, Keeley, Keeley, Keeley, Keeley, Keeley, Keeley.
00:08:23No.
00:08:25They just stopped.
00:08:26That's amazing.
00:08:27I didn't think.
00:08:28If it's not the same guy, it's his son.
00:08:31But it's probably the same guy.
00:08:34That was awesome.
00:08:34Well, anyway.
00:08:35It worked for a while.
00:08:37It's a talk show, folks.
00:08:38The problem with the new breed of superbikes, of course, was that they doubled the power.
00:08:52I think Bonnevilles had, what, 46 horsepower?
00:08:55And Z1 had 80-something.
00:09:01And it was a bit heavier than a Bonneville.
00:09:04Bonnevilles were always quite spare and light.
00:09:09But the chassis, tires, and suspension weren't going to be up to the work in the racing side.
00:09:21And I think this is something that the Japanese later learned to do is, well, the crazy Americans are going to race these.
00:09:28And in order to avoid embarrassment, we have to make them race-worthy.
00:09:34But people were so busy exploring these bikes and having a great time on them that it was a new world.
00:09:47I think it's interesting to note that in the design of the cylinder head, they included axial swirl, which was the great invention of the British tuners of the between-the-wars era.
00:10:02For some reason, the Italians didn't do swirl.
00:10:06But if you flip a Z1 head and look at the combustion chamber side and the intake ports coming in, you can see that it's like directing a hose into a bucket that you're filling.
00:10:18You can make that water whirl around in there.
00:10:21And that's good for speeding up combustion.
00:10:25Another thing that they did was they adopted the British trend toward a smaller valve angle.
00:10:33Triumphs had a 90-degree valve angle, which was from the 1920s.
00:10:38And Burt Hopwood, who designed everything, including the Norton Export Twin, just did this.
00:10:49And at Honda, Mr. Eramadri, at the very end, the last designs of the 1960s Grand Prix era, had valve angles in the high 50s.
00:11:06And that's where Z1 began.
00:11:08So it was best current practice.
00:11:13And the odd thing was that it had a roller crankshaft and plane-bearing camshafts.
00:11:20The camshafts had these little insert bearings that were 100% automotive.
00:11:27Automobile crankshafts had run on those plane-bearing inserts for years.
00:11:31So like the Suzuki GS to come, Kawasaki stayed with the older technology of needle-cage, needle-bearing, crankshaft, and great old ball bearings as main bearings.
00:11:46So it was – it had some connections to the past in that respect.
00:11:55But of course, like all modern engines, it was unit construction and had a great big old clutch.
00:12:02And it was a well-thought-out design that lasted for years, did a good job.
00:12:10Well, considering where Kawasaki came from, I mean, they were doing the W-1, which was a BSA-like parallel twin.
00:12:18Yes.
00:12:19Not really necessarily what the American market was looking for and certainly not differentiating.
00:12:25They certainly had the two-strokes, which made quite an impression.
00:12:29They did.
00:12:31They were fabulous.
00:12:33And it was almost like that was a completely separate undertaking.
00:12:39They started out with the little singles.
00:12:43Then they graduated to the A1 and the A7, which were 250 and 350 twins.
00:12:48And they had disc valves with carburetors sticking out their ears.
00:12:52Sorry, these are pistons sticking out my ears.
00:13:00Yes, sir.
00:13:00They weren't – they didn't define any new category.
00:13:07But the H1, when it arrived, definitely did because it became king of the night.
00:13:12And then they followed that up with the H2, which was a 50% increase in displacement.
00:13:18And that basically said, forget drag racing, the rest of you.
00:13:22We're here.
00:13:23Yeah, king of the night.
00:13:24Kevin Means, king of the night is those street racer folks getting out there and throwing the clutch on XLCRs or –
00:13:30sorry, excuse me, XLCHs and all that going off at the Hess Station in Florida during Daytona Bike Week.
00:13:39Rolling money out.
00:13:40So, yes.
00:13:42Yeah.
00:13:43So, I think that Mr. Inamura, who was the engine guy on Z1, did his homework.
00:13:55He delved into best current practice.
00:13:59And where Honda had chosen a single overhead cam for CB750, Mr. Inamura went all the way to double overhead cam.
00:14:10Which, of course, eliminates the extra weight of rocker arms.
00:14:14You have a cam going down the middle of the engine and these rocker arms that are ticking back and forth.
00:14:19The rocker arms are convenient because you take off a cap and you can unscrew the little clearance adjuster.
00:14:25And in moments, you – oh, that one's good.
00:14:28That one's – all right, that one's good too.
00:14:33On you go down the line.
00:14:34But Kawasaki had shim over bucket valve drive.
00:14:43The camshaft drove a cylindrical inverted bucket that sat over the spring.
00:14:51And clearance was adjusted by changing the thickness of a little shim that was retained on the top of this tappet by a ridge around the side.
00:15:03And it was just fine if you didn't mess with the red line.
00:15:08But, of course, Americans are known to mess with the red line.
00:15:13They were spitting shims.
00:15:15And, of course, the shims were made out of hardened steel.
00:15:20So nothing was going to eat them up and live to roll another day.
00:15:28So that was sort of the origin of that engine.
00:15:35And when American superbike racing started in about 1975 or 6, the AMA decided, oh, well, we have to make room for these because people are racing them just as Moto America has made room for baggers.
00:16:00And they called it heavyweight production at first.
00:16:06And all these private builders were getting out there and spitting some shims.
00:16:13And Mr. Yoshimura got involved.
00:16:16He was running Kawasaki's at first before he made his gentleman's agreement with Suzuki.
00:16:22And when the whole scene became quite competitive, I think that Japanese designers began a second level of study because they said, okay, we've entered the market.
00:16:39We've sold a lot of product.
00:16:40Now, to stay in the market and to maintain our reputation for reliability, we will have to improve the handling, we will have to improve the engine durability, we will have to improve the suspension.
00:16:54And when Mike Baldwin described to me going out onto the banking at Daytona from the infield at Turn 5 on the new 1983 Interceptor, he said, 750 Interceptor, he said, you know, he said, normally you upshift there because you want the rear wheel disconnected from the engine when you hit that bump.
00:17:22He said, but with these new technology dampers, he said, you could just gas it through there.
00:17:29So big progress was made off of the springboard of those first generation big four strokes because they weren't that good in comparison with what was possible, but they were wonderful in comparison with what went before.
00:17:52I think there was some talk that Z1 would be, would have a role, something like what was discussed for Honda's GL1000, namely a long distance semi-touring fast conveyance.
00:18:13And I think that what came out of it was that the motorcycle was the continuation of the sport bike direction that had been set by CB750.
00:18:27And so when the first level of super bikes ended, 1982, the AMA decided, well, these things are, are getting pretty fast.
00:18:45We'd better reduce the displacement to 750.
00:18:48It wasn't long before they were right back at whatever speeds that they'd achieved before.
00:18:57Rob Muzzy was able to get just over 150 horsepower at 10,500 on his Kawasaki-based super bikes that were ridden by the memorable Eddie Lawson.
00:19:14Yeah, sure.
00:19:15And Wayne Rainey later.
00:19:16Oh, there's great.
00:19:18We got great photos of Eddie and Wayne.
00:19:20In fact, in your super bike book, there are beautiful, beautiful photographs of Eddie and Wayne doing things.
00:19:25John Owen's photos.
00:19:27Well, I think those, where am I going here?
00:19:35Well, Muzzy was making 150 horse.
00:19:37Yeah, he had quite a struggle to make his race engines as reliable as he wanted them to be.
00:19:47For example, there were some connecting rod breakages.
00:19:51So he had three levels of cure for this.
00:19:55The first one was to get a big plastic bag and let one connecting rod at a time stick out through the plastic bag protected by big rubber band or duct tape and polish the surface of the rod in the area where the failures were occurring.
00:20:14And the second level was to have some connecting rods made and to build up the crankshafts in the U.S. from parts.
00:20:27And the third level was crankshaft comes from Japan ready to race.
00:20:33And I think they finally moved to a Canadian crankshaft, a Canadian model.
00:20:40And I think the crankshafts originally weighed 32 pounds or so.
00:20:46Oh, my.
00:20:46And a fascinating fact is that Muzzy told me that he had never had any luck with getting a light crankshaft to top end at Daytona.
00:21:00And it's not surprising if you look into the dynamics of cam drive, because Honda found with one of their Formula One designs that if they operated the valve train by an electric motor with a flywheel on the end of the camshafts, that they would get X as the RPM of valve flow.
00:21:24Presumably, they're looking at it with a stroboscope so they could see the valve flow developing.
00:21:30And then when they drove the camshafts from the engine's crankshaft, what they got for valve flow was X minus 1,500 RPM.
00:21:46Because crankshaft is a very upsetting thing to be driving anything else that has to be precisely timed.
00:21:53Because it's like it's being punched around in a circle by all those combustion events.
00:22:01So its speed is warbling terribly.
00:22:04And this is why so many engines have trouble when they're young with the cam drive.
00:22:10So this was one of those areas where with a nice heavy crankshaft, the drive to the cams would be relatively stable and you'd be able to get right up close to valve float and gear for it.
00:22:31Have all kinds of top end.
00:22:32But if you put in a light crankshaft figuring, well, the place to make hay is in the infield where acceleration is what counts.
00:22:40Then when you got on the banking, it could be that the valves were sort of saying, you know, I just don't know when to open and close anymore.
00:22:48Somehow I've lost the rhythm here.
00:22:50And so you will find on some engines, for example, RC-30, some of those versions had flywheels on the camshafts.
00:23:03And that's just to settle down some of these dynamics.
00:23:07This is, you know, this is an automotive point, but the Aston Martin, the 3.7 liter, like the engine in the DB4, the James Bond DB5, the inline six.
00:23:21Yep.
00:23:22Double overhead cam, big, long chain that goes around the whole thing.
00:23:27And then the distributor is on the other end, the tailing end of the cam.
00:23:33Yes.
00:23:34And when I saw that, I thought, that's probably fine.
00:23:38It's probably fine on the street.
00:23:39But I'm guessing that if we really hammer on this thing, we're going to get a lot of spark scatter because, you know, the cam has got to be doing this.
00:23:47Yep.
00:23:47And then you're putting a drive on it.
00:23:50And it's interesting to think of that.
00:23:52We take, you know, we look at our tachometer and our tachometer says 7,000 RPM and we kind of envision it as this constant.
00:23:59And in fact, the crank is just going, oh, you know, it's accelerating, it's stopping, especially with a 184.
00:24:04Because the pistons, the two center pistons are going up to come to a complete stop and the outside two are doing the same.
00:24:10And then, nope, we're going to get 7,000 Gs and head in the other direction.
00:24:14You know?
00:24:15Sure.
00:24:15It's just, it's, it's, it's wildly variable.
00:24:19I love hearing stories.
00:24:20The crank shaft, yeah.
00:24:21Yeah, yeah.
00:24:21All the things.
00:24:23And for you to talk about, you know, the three stages of, you know, Muzzy trying to make his connecting rods survive and doing that.
00:24:35Well, just getting in and saying, I'm going to polish this or we're going to shot peen, we're going to take this part we have and we're going to figure out how to make it work.
00:24:41I think that still exists today, but it seems maybe less so because a lot of our stuff is better.
00:24:49That's true.
00:24:50So good, in fact, yes.
00:24:51Yeah, it's, it's better, but also I feel like as a culture, we've deferred to an expert and that would be, we're not the expert.
00:25:00I'm going to build a race motor.
00:25:02I have to get X rods or I have to go to the person who does the thing.
00:25:07And we don't necessarily try to blow it up and solve it ourselves and do something that the other way.
00:25:12Get our own answers.
00:25:13Yeah.
00:25:13Well, and then there's the other point, which is that oftentimes when the story of some engine is told, they say at this point they substituted this material or they made this change in the valve springs or what have you.
00:25:31And that makes it sound like engineering is a very deliberate thing, like yourself with your coffee, that it's, I'll have a sip of coffee and I'll look at this drawing for a while and then it'll be lunchtime.
00:25:44But in fact, those changes are driven by desperation.
00:25:49And there are people upstairs who are thumping on the floor.
00:25:53Bring the solutions to us now.
00:25:56Desperation, changing the world since forever.
00:25:59Through desperation, yes.
00:26:00And I think, uh, that's one of the most exciting things about racing is to get in, get into the desperation because I noticed that the original interceptor valve springs had like 13 turns and S and S valve springs work best when they had three and a half turns.
00:26:25So, uh, so, uh, so, uh, why was that because what you want is for the natural frequency of the valve spring.
00:26:36If you pluck at it, like it's a slinky, how fast does the wave bounce back and forth between the ends of the spring?
00:26:43The fewer the fewer the turns, the stiffer the spring, the higher the frequency.
00:26:49And it wasn't a good idea from a metallurgical standpoint because the metal said, oh, I need a nap.
00:26:58I'm tired.
00:26:59Oh, click.
00:27:00I've broken in two.
00:27:01And so they had to come up with, uh, better valve spring material.
00:27:08And of course, yeah, fewer coils, fewer.
00:27:10Yeah.
00:27:11I mean, in order to implement the fewer coils, the concept worked.
00:27:15Now we have to make it last, make the material work.
00:27:18And this is just, this is a part of the desperation.
00:27:22And you see, when you look at suspension springs, uh, the really fancy suspension springs very often have few coils.
00:27:32It's, it would be a high performance spring and a lot, or fork springs can be like that where you don't have as many coils.
00:27:38And then you get something that's a low grade material and it's got a zillion coils in it.
00:27:43And it's a, it's a material question and it, you know, that other one, uh, Steve Scheibe, uh, who was the engineer for Harley Davidson's VR 1000 super bike project back in the nineties.
00:27:57Uh, he said, people are just increasing the stress on valve spring material like crazy because they're trying to protect the spring from, from what they call surge,
00:28:12which is just end to end vibration.
00:28:14So many fatigue cycles that's a material fails.
00:28:20So then they had to go to vacuum remelt.
00:28:23You heat the material up in a vacuum and let the impurities evaporate.
00:28:32Well, we had dual valve springs to help, uh, reduce vibration, right?
00:28:37Those, the springs kind of resting on each other, nesting inside of one another.
00:28:42Almost pressing against each other.
00:28:43Yes.
00:28:44A press fit.
00:28:44And there were those flat wire dampers.
00:28:47Um, all these, uh, dodges are tried from time to time to find out which one is going to work before we have to go to Pomona next weekend.
00:28:58Um, and that's the creative desperation.
00:29:01And I think that's why, um, I, I urge modern motorcyclists to have a sip, drink the whole thing if you like, because get out there, get your own answers, break some parts.
00:29:19But, of course, it voids the warranty.
00:29:24Yeah.
00:29:24Well, going back to your book, one of the lines, uh, the sport bike performance handbook, uh, I think one of the great lines that was just tucked away, uh, in the oil change section was, use your natural curiosity.
00:29:37It's so easy to say, but, uh, yeah, you were talking about doing the oil change and, and you said, use your natural curiosity and, and look at, examine what's in the oil.
00:29:48What color is it?
00:29:48Does it stick to a magnet, et cetera?
00:29:50There was, you know.
00:29:51Is it silvery looking?
00:29:53Yes.
00:29:53Is it, is it, is it kind of gray and pasty?
00:29:57Well, there was a, a point when, uh, Japanese super bikes did not win super bike races.
00:30:06It didn't last long, but it was a definite period of time.
00:30:10And what was happening there, of course, was that, uh, European manufacturers placed a higher value on handling than Japanese companies did at that time, because the Japanese companies were wedded to the quarter mile time and the top speed in an hour magazines.
00:30:33I have some data that we can get to.
00:30:35So I do have numbers from the era we can talk about.
00:30:37Um, but, uh, for a time, the Japanese super bikes could not use their top speed because their chassis would begin to weave before top speed was reached.
00:30:55Now, normally a motorcycle designed so that every motorcycle has a weave threshold, but thankfully most of them can't reach it.
00:31:03They're not fast enough.
00:31:05And that's the desired ideal.
00:31:07Um, and then, uh, I think, uh, Kawasaki won the, won the, uh, super bike championship and it put an end to that European flair era.
00:31:21But, uh, uh, the thing that, uh, the thing that was talked about at the time incessantly was this notion that super bikes are a higher level of racing.
00:31:35You have to have a, an older, more experienced rider who knows when to show courage and when not to, and as for those young whippersnappers like Kenny Roberts that's winning the world championship and so forth, well, they give those guys bikes that are actually made for racing.
00:31:53So, of course, uh, so then Kawasaki decided, uh, anybody in this office got, uh, a phone number for this kid, Spencer?
00:32:04Uh, yes, uh, look here.
00:32:06Oh, here it is.
00:32:08Well, they put old Freddy on one of their bikes.
00:32:13He disappeared up the road and the theory of older, more experienced and wiser men just went poof.
00:32:22Forget all that nonsense and everything moved on and that's why, uh, they had Eddie Lawson on the thing because he would find out how to get around the course.
00:32:41I watched him come over the top of the corkscrew in practice and every lap he tried a different thing.
00:32:48Um, that's what riders do.
00:32:51They're trying to find out what works.
00:32:54They're not just going out there and twisting it up.
00:33:00They're looking for solutions.
00:33:02And once they've got a workable one, they're going to go with it lap after lap.
00:33:07It wins races.
00:33:10So, uh, Kawasaki and later the GS Suzuki's became the basis for,
00:33:18uh, drag racing class, um, pro stock motorcycle.
00:33:25And I believe the Suzuki's are in the form that they've, that into which they have evolved after many years are still using roller crankshafts.
00:33:37Amazing.
00:33:37Um, at one point there were so many, uh, Z ones being treasured by riders.
00:33:48Who wanted to keep riding them that Kawasaki said, we will produce a limited run of new cylinder heads for that motorcycle.
00:33:57Because, uh, not everybody wants to go to the high class machine shop and say, I want all new valve seats.
00:34:04And I want the valve guides replaced with guides that whose axes are actually pointed the way that says in the drawing.
00:34:13Uh, and that was a good thing for those, um, people who wanted to continue enjoying their Z ones.
00:34:24Well, it was, uh, uh, uh, when the Z one came out, you'd talk about quarter mile times and sure enough, we have those, um,
00:34:31the Norton 850 commando did a pretty, pretty peppery 1296 at 102, uh, miles an hour.
00:34:42It's not, not bad for the day.
00:34:43The CB 750 did a 1338 at a hundred and, uh, won the top speed battle at 123 miles an hour.
00:34:53But the Z one came along to the 1261 at one Oh five, right out of the box.
00:34:57We got all these beautiful pictures, probably at the now defunct Orange County international raceway.
00:35:03Oh, C I R.
00:35:05Oh yes.
00:35:06Yeah.
00:35:06That was, that's where we used to, that's where we used to do it.
00:35:09And, uh, now we, we use a, a landing runway out in Riverside, rent the runway.
00:35:15And we do the same, go throw the clutch.
00:35:17So we got, but that's a big jump.
00:35:19I mean, that's a 1261 versus a 1338, you know, made the Honda look little, little stayed at that time,
00:35:25but it wasn't long until the Honda twin cam came out.
00:35:30Yeah.
00:35:32Changed, changed their production.
00:35:35Yeah.
00:35:36Well, they had to, they had to meet the competition, didn't they?
00:35:40And they, a lot of that stuff was developed for endurance racing that Honda had become involved in originally with CB 750.
00:35:49And so that acted as a, uh, rich source of desperation for development.
00:36:03The same thing has been proposed to me, uh, with regard to the development of aircraft engines during World War II.
00:36:10Piston engines, of course, they all were.
00:36:12And the notion that, uh, now they move from a single stage supercharging system to a dual stage supercharging system.
00:36:22And it makes it sound all very academic, but in fact, uh, that's what you do when the Germans can climb above you and be immune.
00:36:32You have to, you have to cram air into your engine denser than what's outside the window.
00:36:41And you may need a second stage of supercharging.
00:36:44There are some two-stage supercharged automobiles out there now.
00:36:49It's an adventure.
00:36:50I think, uh, the AMA, American Motorcyclist Association, as it became, did a good thing for racing in the sense that they, in the early days of Superbike, 1000cc Superbike, they said front forks may be altered or replaced.
00:37:15Swing arms may be altered or replaced, meaning we know that those components, which were made for production and to hit a price point, may not be satisfactory.
00:37:27They may even be embarrassing if raced.
00:37:30So go for it, boys.
00:37:33Those engines weren't reliable to begin with because of things like the connecting rod problem that just described.
00:37:41Uh, Suzuki, at a point, had a problem with rod bolts.
00:37:46Uh, there were all kinds of things.
00:37:50Pistons are always a problem because they develop fatigue cracks around the wrist pin.
00:37:55The wrist pin is saying, I'm, I'm going this way.
00:37:58And the piston is sort of, well, I like it where I am.
00:38:01And so, eventually, the wrist pin pulls right out.
00:38:06Just tears the metal out of that wrist pin boss.
00:38:09In racing.
00:38:11So, it took time for all of these things to get, um, upgraded.
00:38:17For everyone to cross out the obsolete materials on the drawing and enter the better stuff.
00:38:25And so, the second generation of Japanese Superbikes was a huge step forward.
00:38:31Because unlike the Z1s and GSs of the first era, they didn't have to have their chassis sort of completely re-engineered with extra pieces of tubing and gussets and possibly having the steering head sawed off and put on at a more usable angle.
00:38:51But those bikes had, uh, steering that was not overly conservative.
00:39:02I think the usual thing was somewhere in the range of 27 to 28 degrees of steering head rake, which is the, generally the angle of the fork tubes to the vertical.
00:39:13And, um, I think CB750 had 3.74 inches of trail, which is fairly radical for the time.
00:39:27Pretty short, yeah.
00:39:28Um, and I, I'm told by Greg McDonald, the CompuTrack, uh, wizard, that once you get the squat, anti-squat behavior of the rear end of your motorcycle under control, that you can go back to four inches of trail and it isn't slow, it's good.
00:39:55But that's hearsay.
00:39:56Well, what's the, uh, steering geometry on a Ducati MotoGP bike, I wonder?
00:40:05Well, we, we've seen a lot of stuff getting down towards 23 and something.
00:40:11Yeah.
00:40:11And that progress has been, uh, to a great extent enabled by chassis that have stiffness in the desired directions.
00:40:26If you don't have any weight on the front wheel, for example, a Ducati bevel drive V twin, which has the engine way back and correspondingly less weight on the front wheel, you may need a lot of trail.
00:40:46They gave it four and a half inches and a lot of rake.
00:40:50And I think they gave it 30 or 31 degrees.
00:40:52It needed it.
00:40:53And I think they tried to get away with as little as possible on the first generation super bikes to make them as responsive as Triumph and, and, uh, Norton owners were accustomed to.
00:41:10They didn't want any backtalk from Britain.
00:41:15Um, some people told me, well, I talked to one fellow who said he bought a Z1.
00:41:20And he was entirely in love for six months and then he realized that his bike didn't handle all that well.
00:41:29And I think there, there could have been more than one of those fellows.
00:41:36So many things can contribute to that.
00:41:38When your tires wear away from their original cross-sectional contour, all sorts of things can happen.
00:41:45And so the industry's advice is buy more product.
00:41:50Well, the taxing, yeah, the taxing, yeah.
00:41:54This year, this year's model is better.
00:41:56You'll like it.
00:41:58Well, the taxing element was the engine power.
00:42:01It, it said, here we are.
00:42:03And it's going to drag the rest of it, rest of it forward.
00:42:09Just tire contour.
00:42:10We could talk, talk a lot about, we could talk about the, the cones,
00:42:13the contact patch sort of cones that you have, uh, leaned over for years, testing motorcycles,
00:42:22trail braking into a corner.
00:42:24You would get bikes with tires and geometry that would make the bike want to stand up under braking.
00:42:30You could get them, but they would want to fall in Harley Davidson tunes.
00:42:34They won't say for what, but I talked to their chassis guy a number of years ago.
00:42:38They tune for a certain amount of inside bar pressure.
00:42:41So they're, to keep the bike online, it's not neutral steering.
00:42:46It's intentionally not neutral because it, they feel that it gives feedback and that it will be self-riding when you're finishing the corner.
00:42:55And it's, they have a, they have a spec.
00:42:58He wouldn't say, oh, I'm like, what's that spec?
00:42:59He's like, I'm not going to tell you.
00:43:02Um, but you know, the combination of developing tires with motorcycles and all of that work,
00:43:07you can end up with a bike that is beautifully neutral steering.
00:43:12Uh, you can do, you can accelerate, you can break, you can trail brake really hard and, and it doesn't want to stand up and go out to the edge of the corner.
00:43:21It just keeps doing what it's doing.
00:43:23Honda for a very long time was except is still exceptionally good at that.
00:43:27But most bikes, we don't see that anymore.
00:43:31But, uh, you know, a rubber frame Z one with, you know, 80 something horsepower and worn out tires.
00:43:37Just imagine.
00:43:38And, you know, damping, just damping on, on the Z one, you're, you're basically looking at a screen door closer on the fork and the shock.
00:43:46And everybody was like that.
00:43:47It's just, you know, there was nothing there even in the nineties.
00:43:50Fork dampers were, fork dampers were the worst.
00:43:52They had, uh, a rebound orifice, which means that it had V squared damping.
00:44:01The faster the fork extended, the damping force went up as the square, which means very quickly it went up vertically, became infinite.
00:44:10And then there was a, uh, a one way valve that opened on compression so that bumps didn't send you.
00:44:21And that's why that, uh, all those old time girling shocks had the one way valve in them.
00:44:27And gradually, gradually shocks have evolved to the point where their movement is pretty creamy and there aren't a lot of spike producing elements in there.
00:44:42But it has taken time because riders get used to the, oh, these new shocks are great.
00:44:49Oh, why didn't we have these last year?
00:44:51And then after a while, well, there's some of these, there's some new problems here.
00:44:58Could, could, could we talk about it?
00:44:59Uh, uh, so there, it never ends.
00:45:05So the Z one, this, during this period of time, everybody was still making two strokes.
00:45:11It seemed like we had a war between, not a war, but, um, a hedging of bets.
00:45:16Or did we already see the writing on the wall for two strokes in 1973, 74?
00:45:21Oh, they sure did see it because they could see it clamping on cars.
00:45:24And they knew that those people in Ann Arbor would be coming for them because look at the smoke.
00:45:33We used to get new H-1s out of the crate and we'd take them out for a run up the hill in Arlington, Massachusetts.
00:45:43And just like the tip vortices of an airplane flying in, uh, humid conditions, this smoke would come rolling out.
00:45:54So, uh, the mechanics turned down the pumps and we came to realize that the oil pumps had been set for a worst case.
00:46:06And so, but meanwhile, the damage is done.
00:46:11Why is that thing smoking like that?
00:46:13I'm going to make a few calls.
00:46:14And eventually, uh, in 84, it was about the last year that, uh, two strokes could be sold for the street of any kind.
00:46:26RZ 350, 85.
00:46:29Yeah.
00:46:30Cats in the pipes.
00:46:31And, you know, we, gosh, we loved it.
00:46:35We loved what was great about two strokes.
00:46:38And what is great about two strokes is that lightness and simplicity and essentially behaving like a double displacement engine.
00:46:47You know, I had a 79 RD 400 Daytona special.
00:46:51That was just a used bike when I bought it.
00:46:53It was just an old two stroke, you know, nothing wasn't a collector item.
00:46:56It was just affordable and it was the fastest thing I could afford.
00:47:00And it, it didn't have the number of the new Ninja 600 R in 1986, but it was there.
00:47:07Yeah.
00:47:08And that's why I bought it.
00:47:09So.
00:47:12Well, I think that, uh, last week when we talked about the Honda NR 500, I mentioned that it's much cheaper to increase the horsepower of a two stroke.
00:47:28Then that of a four stroke.
00:47:30In the case of the two stroke, you're changing the shape of ports in the cylinder.
00:47:34Some of that work can be done with a hand grinder.
00:47:38Uh, that then has to go to the foundry department and they have to learn to cast it in that shape.
00:47:44Uh, the other work goes into the exhaust pipes and those are lightweight components.
00:47:51Uh, you can, you can make a set of test exhaust pipes, straight ones for the dyno in a day.
00:47:59So on the other hand, with the NR 500, the 22 kilograms of extra material, that was the cylinder heads.
00:48:10When you want to make a fundamental change, let's change the valve angle, let's change the ports, let's change this.
00:48:16It means big money.
00:48:19Lots of big, important parts have to be made a second time.
00:48:23So that was the charm of the two stroke was that a, a, a no box guy with a die grinder in one hand and a gas torch in the other for the exhaust pipes could make something frightening out of an RD 350.
00:48:39And I made something frightening about, uh, with, uh, with my RD 400 and what happened, I high sided it as so many of us did.
00:48:50Well, that's the engine getting ahead of the chassis suspension and tires.
00:48:54That's getting ahead of the riders.
00:48:55Well, okay.
00:48:58So maybe not the best choice is a first street bike.
00:49:02Who knows?
00:49:02But, but, but I think, I think to sum up, I think that the Z one was well planned for the market and they weren't in any hurry because when the CB 750 came out, um, it was a couple of years before they went with, they went to production with the, with the 903.
00:49:24And I think that, uh, Mr. Sam Tanegashima, who has been described as Japanese American did a lot of new product research in the U S and it wasn't a case of, um, I always feel sorry for, for the engineers at Suzuki put blood, sweat and tears into the, the GS 750.
00:49:54Uh, uh, GT 750, the three-cylinder two-stroke or water Buffalo or kettle and the RE5 rotary because the engineering work was expended.
00:50:12The market failed to confirm it.
00:50:16It was kind of like, um, Honda's Pacific coast.
00:50:20The only two, the only ones I've ever seen was a group of five who are being ridden by Honda executives back to California from Daytona that year.
00:50:30And one collector bike that I saw at the gym.
00:50:36Yeah.
00:50:36Or any other.
00:50:37Yeah.
00:50:37They were around.
00:50:38I mean, in Southern California, they were around at the time.
00:50:41And actually I worked at a coworker at, um, at cycle news when I was working back there, who was an adherent to the Pacific coast, just loved it.
00:50:50And he was a motorcycle guy, you know, he did.
00:50:53Yeah.
00:50:53He did motorcycle things, but, um, you know, getting around California at the time, it was not bad.
00:50:59It was narrow, it had storage and so forth, but in terms of inciting passion or, or causing feelings of love, uh, to the wider market, it wasn't a success in that, in that way.
00:51:12Yeah.
00:51:13I think falling into the practicality trap.
00:51:15I mean, you know, what did the Z one do?
00:51:17The Z one came to market with big power, huge four cylinder for the time, the fastest quarter mile time and styling that felt like a cozy blanket.
00:51:30Look cool.
00:51:31It was very nice.
00:51:32Yes.
00:51:32I think so.
00:51:33But it looked, it looked good.
00:51:34It wasn't too new.
00:51:35It wasn't too out there.
00:51:37It just looked like a big burly motorcycle and it had, it delivered, it delivered on its muscular looks and it was there and that, and people, people went crazy for that.
00:51:47And then we got Z one ours with those, with that fairing and the smoke tinted screen.
00:51:52And we have a story on a Z one R, uh, being, uh, tuned by Yoshimura at the time and running through quarter mile.
00:52:00And, and, um, one of the guys at Yosh apologizes because it's a quarter mile test.
00:52:06They had the bike at the quarter mile and it had, it had a pipe.
00:52:10It had a high, high rise, you know, high clearance, Yosh pipe.
00:52:13If you wanted to change the oil, you had to take the pipe off and drop the, to get the oil filter.
00:52:18Um, it had no center stand because of the pipe routing, but it, it increased the cornering clearance, but it was really a core.
00:52:24It was a quarter mile story.
00:52:25They were at the drag strip.
00:52:27They were changing jetting.
00:52:28They were, they were doing all of these things.
00:52:30And the Yoshimura folks actually apologized because they weren't accustomed to doing drag strip testing.
00:52:40They were really, you know, road race people.
00:52:42And they're sorry, it's taking us a little bit longer.
00:52:44And the results were great.
00:52:45They were, they were doing, uh, one 20 something when close to one 30, I think in the quarter mile.
00:52:53So they were really, they were making power.
00:52:55It had cams and, you know, it was not, it was not running below 5,000 for a while as they sort of tried to figure out how the jetting was going.
00:53:05The, the turbo that came later, the Kawasaki sort of semi factory turbo with the MOLLE, uh, MOLLE design paint, kind of that rainbow gradient.
00:53:14Oh, MOLLE, yes.
00:53:16Yeah.
00:53:16Oh, wonderful.
00:53:18Um, yeah, it just, uh, it hit.
00:53:23It, it made big power and it resonated with the market.
00:53:26Yes.
00:53:27I think that it, it, um, makes me think of the GM's great stylist, Harley Earl, who said, you must lead the market, but not by too much.
00:53:40And I think that's why the bulbous tank, the generally, uh, British twin inspired look, but enough bigger to say,
00:53:52wait a minute, this, this is a good size bear right here, but not too big.
00:53:58And that's a topic for another show, but the size of motorcycles, you know, when you go back to a Triumph Bonneville, uh, you know, 70, 69 Bonneville or anything before that, pretty much.
00:54:11Cause they were very similar from short wheelbase.
00:54:15Short wheelbase.
00:54:17Uh, they were very handy.
00:54:19They steered beautifully.
00:54:20They were fun to ride.
00:54:22They felt great.
00:54:23Steering.
00:54:23You could see right through them.
00:54:25They were transparent, but they were of a good size.
00:54:28And you know, the, the, um, oil and frame bikes that came after, you know, what, seven, 71, the oil and frame bikes, they were derided for having a high seat height.
00:54:40And it was like, I think it was barely an inch higher.
00:54:44It was not significantly higher, but they looked a little bit different and the seat went up and it changed kind of the vibe of the bike.
00:54:51And people were, people were, were disappointed in that going to today, you have the speed, uh, the speed twin 1200 and it's, it's a spectacular motorcycle, really, really fun bike.
00:55:07It's big.
00:55:08It's, it is pretty beefy.
00:55:10The bike you actually want, if you're trying to evoke what Triumphs were is the 900 because it's smaller.
00:55:18It's, it is the natural extension.
00:55:21And that, that size thing, I think that's one good thing about, you know, MTO sevens and, and all of that is it, it, it acknowledges the existence of a human of a certain size.
00:55:35Like if you look at our 80 GS and now we have our 1300 GS, the 1300 is a spectacularly capable bike.
00:55:42It's lighter.
00:55:43It has more power.
00:55:44They've done all these wonderful things, but it is not what, what the middleweight adventure class is now, which is an F 900 and the F 900 in terms of riding off road, the size, the narrowness, the lightness.
00:55:58It's a, it's easier to handle.
00:56:01You may not want to do a, as much as a 17 hour a day with a lot of highway, you know, I mean, it would, it's capable and comfortable.
00:56:10But when you get the big, so I think that was, what was nice about the time is, you know, Norton Commando.
00:56:17Wow.
00:56:17That's a big bike.
00:56:18When I got on my RD 400, not a big motorcycle, but, and I was six two when I got it, but I got on it and, you know, compared to XR 75s and MT 250 dual sports and KE, whatever Kawasaki's I'd ridden.
00:56:32It felt really, really big and imagine, you know, imagine getting on your, draping yourself over a thousand CC super bike, uh, versus a Z1.
00:56:43Yeah.
00:56:46And now it's just an antique, but the Z1 really came in and, and put a stamp on the class and took power to a new level and, uh, helped revolutionize the four stroke era and, and super bike and, and all of that.
00:57:00Um, and one of the things that, that was described to me by, uh, some of your testers was this notion that you could go out and run in the dark of night in the secret place in the desert.
00:57:17And when you came back from making your runs, the engine acted like it had just gone for cigarettes at the corner.
00:57:25It sat there and idled.
00:57:28So it wasn't trying hard.
00:57:31And I think that was one of the great things about Japanese machines was that they did what they did casually.
00:57:41You didn't get the impression of, of terrible strain and, and reaching for something barely within reach.
00:57:52Yeah.
00:57:53I don't know if there's a cultural thing going on with, you know, British engineering, like we need to punish ourselves.
00:58:02Like, okay, we're going to use a tower shaft with multiple shims and we're going to just, we're going to commit to shimming this at least three times to get the bevel gears to fit.
00:58:13And, and all the, just how many different weird operations and not that there aren't quirks and, and pain in the ass things with Japanese bikes, but you take a sport bike now.
00:58:26And for the last 35, 40 years, even close to that, you could go to a dealership, ride the bike, break it in, get your 600, do the oil change, ride it to a racetrack.
00:58:41And then put 5,000 miles on it, on a racetrack, just change the oil, adjust the chain tires, do all this stuff.
00:58:50Just keep doing that, going as fast as you can.
00:58:55And it, it makes no difference.
00:58:57Yeah.
00:58:58You could never turn it off.
00:58:59You could, you could go to the racetrack, do the laps and park it on the side stand idling and go to bed and wake up in the morning and the temperature would be the same.
00:59:08You'd have to fill it up with gas and then you could just, it would just idle forever.
00:59:13You could just keep putting gas and it would, it would idle for 15 years.
00:59:17So.
00:59:18Kawasaki made that 24 hour run at Daytona with Z1s and what they averaged 109 miles an hour.
00:59:25Um, I'm sure they had a look at that record and said, yeah, I think we can probably do it.
00:59:34Uh, because this, this is the thing.
00:59:38When, when I was a working guy in, uh, in Denver, Colorado, there, there was a customer who had a 12 to one triumph that he was running on aviation gas that he kept in a shed behind his mother's house.
00:59:53And that was one 15, one 45 gasoline.
00:59:57And he was definitely pushing it to make himself King of the night.
01:00:04Uh, but the Japanese bikes are based, were based.
01:00:11What was so important, a difference between them and what had gone before was that Japanese mass production could sell at an attractive price.
01:00:22Features like electric start, double overhead cam, what have you, that were not available at any price from another manufacturer at a competitive, uh, tariff.
01:00:37You could, you could afford it.
01:00:39And I think that's, that's been the thing.
01:00:42Design is one thing, but production is what delivers it to the customer at a price.
01:00:48The customer can afford.
01:00:50And art in itself.
01:00:52Yep.
01:00:55So the beat goes on.
01:01:00Well, thanks for listening folks.
01:01:02It's, uh, Kawasaki Z1 and more.
01:01:06And more.
01:01:07Wandered a little bit there, but, uh, it was a defining time.
01:01:11And, um, it probably, well, I mean, you know, H, H twos and all that certainly defined Kawasaki as an engine company, but they had a, a lot of, uh, rep, you know, that reputation is like, oh yeah.
01:01:25We build engines that run even to the ZX nine era, you know, into the, in the two thousands where it was kind of a longer, it wasn't as focused as an R one, you know, let's call it 2000.
01:01:37So the R one was, you know, short light, big power, but, uh, ZX nine still, uh, still made competitive horsepower, but it was really, uh, the engine was the highlight on that model.
01:01:50Well, thanks for listening folks.
01:01:52Uh, see you in the comments, um, like comment, subscribe, et cetera.
01:01:57Uh, if you're on Spotify, uh, give us a rating down there, help us out.
01:02:01Um, Apple podcasts, et cetera.
01:02:04Uh, we'll see you next Wednesday.
01:02:06Thanks for listening.