The Honda NS500 and NSR500 two-stroke four-cylinder grand prix bikes were hotbeds of innovation and showed exceptional dominance in the hands of genius riders such as Freddie Spencer, Eddie Lawson and, particularly, Mick Doohan, winner of FIVE consecutive world championships in the 1990s. Technical Editor Kevin Cameron has deeply studied the NSR500 and it shows in this podcast—he knows a lot of stuff about a lot of stuff, but two-stroke GP bikes are a strong suit! Listen to him and Editor-in-Chief Mark Hoyer discuss the NSR500, screamer vs. big bang, water injection and lots of other trickery that helped the bike dominate the final seasons of two-stroke GP racing.
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SportsTranscript
00:00:00Welcome back to the Cycleworld podcast. I'm Mark Horry, the editor-in-chief. I'm with Kevin Cameron, our technical editor.
00:00:06This week's topic is the Honda NSR500, starting with the NS500 triple in 1981 and everything that evolved from that.
00:00:15Honda finally made the decision not to try to do really neat, technically complex four-strokes and embraced the pipe organ.
00:00:27I think the ultimate expression of the NSR500 was really Mick Doohan's between 94 and 98 when he won five championships, which everyone decried as boring.
00:00:40And I guess in some senses, that's right. It was boring in the sense of it wasn't the hammer and tong battle and the brave soldiers clawing it out to the death.
00:00:53But when you get somebody who's technically dominant like that, it is a beautiful thing. 97 was his best season, 12 out of 15 races dominant in 97.
00:01:05How did we get there, Kevin?
00:01:13Well, I think Honda had, of course, some experience in motocross by that time. By that time, I mean 1981, because that was well accepted as a two-stroke area.
00:01:28And it was not an easy development because Honda started out swinging two bats with the 500, which had the fuel tank hung under the engine and the exhaust pipes rooted over the top of the engine.
00:01:50The theory being that when the English talked about a low center of gravity being the heart of good handling, nobody really questioned it.
00:02:02And Honda went ahead and built this thing, and it was slow in roll. It didn't change direction very quickly. And that was a handicap, which prevented them from winning the championship in 1984, which was the year of introduction.
00:02:22And instead of following the clear trend toward twin aluminum beam chassis, this bike had a kind of, oh, a collection of an omega-looking element and a lot of aluminum tubes going this way and that with carefully worked out junctions.
00:02:46And when they got it into combat, it didn't turn well. It pushed the front. Freddie wanted the engine moved back. It was eventually moved back. I think by South Africa time, they were thinking about it.
00:03:10And it improved it. But basically, what Honda was doing in this period was catching up from zero to where two-strokes were. And the previous bike, the NS3 or NS2, whatever they called it, was a triple.
00:03:34And it had been designed according to Shinichi Miyakoshi's idea of let's build a 250 with 100 horsepower. And he had gone to the Dutch GT, and he had seen that the twins on that course were remarkably fast.
00:03:57Not as fast as the 500s, but putting 100 horsepower into something as light as a 250 looked like a good combination. And that's what they built for 1982.
00:04:13But Austin would be a good track for that type of strategy. Not every track would be a good track for that type of strategy.
00:04:21True. But the crazy thing is that that three-cylinder bike won at Spa in Belgium, which is a wide open throttle kind of place.
00:04:36And part of that equation was that the three-cylinder being fairly light and having less power overall, started the season with 108 horsepower, it didn't tear up its tires the way the Suzuki's and the Yamaha's were doing.
00:05:00So at the end of a race, Freddy would have the others at his mercy quite often, because that little bike didn't have the torque to go through corners in a continuous slide controlled by throttle.
00:05:24And I think at Silverstone, Freddy had to do most of his turning just as the engine, as the tachometer rose through the torque peak at a couple of places in a long sweeper.
00:05:41So his line ended up looking like what the English used to call a thrupny bit, which is a coin that is a polygon and not a circular disk.
00:05:54Helps to be Freddy Spencer in that situation, doesn't it?
00:05:57Oh, yes. And of course, Freddy, well, when I first had the opportunity to talk to Marquez, he said his first year was every lap like qualifying, he said.
00:06:18And so I think that Freddy was doing something quite similar. He was pushing himself to his maximum and his maximum was appreciable.
00:06:35So in 83, the power of the triple rose finally to 128 horsepower. The power band was always the same. The engine came in at 98 and it signed off at 11.
00:06:53So that gave him 1200 RPM to work with, pretty much like an old time Max Norton.
00:06:59And that's a good reason to have a six-speed gearbox.
00:07:03Freddy would be given a new engine and he would put 300 kilometers on it.
00:07:13And the main bearing saddles, these were magnesium crank cases, would be sort of oval.
00:07:21And those cases would be sent back to Japan, be remachined and rebored for one more 300 kilometer go.
00:07:32Because he would hold on when he couldn't get at the shift pedal because the bike was leaned over.
00:07:39He just let it rev. What else could he do?
00:07:43And it pounded the cases pretty well. And of course, magnesium is not the most stiff metal you can find. It's sort of like super cool butter, but it's light.
00:08:00Electrified dirt, it's often called.
00:08:03Yes. Was that Harold Willis at Velocette that used that term?
00:08:08I think so, yeah.
00:08:10What about ATAC, Automatic Torque Amplification Chamber?
00:08:15One of the things that you have to bear in mind about this era is that in some cases, the manufacturers were willing to copy.
00:08:25For example, when the Big Bang firing order came along, everybody had Big Bang as soon as they could put another crankshaft in it that had the crank pins moved.
00:08:36We'll have to spend some time talking about that. Go ahead.
00:08:41But in other cases, there was that Honda way or that Yamaha way.
00:08:50And Yamaha's way was two counter-rotating crankshafts. Honda way was one crankshaft.
00:08:59And each company on the quiet built what they took to be what the opposition was running, just to check that there wasn't something they overlooked.
00:09:15And this is very common. Manufacturers do this kind of thing all the time.
00:09:21But in the case of the three-cylinder, evolution of the engine in terms of reliability was continuous.
00:09:35They were constantly getting new pistons.
00:09:38There was all kinds of concern about connecting rod, big end bearing life.
00:09:43And they were, in Jody Nicholas's words from long ago, holding it together with their knees.
00:09:54And this is what happens in racing.
00:09:57It isn't something that can be determined in advance by using mighty supercomputers.
00:10:05There's no substitute for experience.
00:10:09So you get to the track. There are the engineers. They have puzzled looks on their faces.
00:10:15There's Freddy with his engineer, Irv Canemoto.
00:10:22And they're doing whatever they can.
00:10:26So Freddy was champion in 1983.
00:10:32And everyone else had four-cylinder bikes.
00:10:39And they had been blindsided by this tire-kindly, low-powered bike with a mad genius as rider, Freddy.
00:10:55The wonderful thing about Freddy is that he always had that choir boy innocence in his face.
00:11:03He looked like he's glad to see you.
00:11:06But it could be that he just came through the ceiling in another room.
00:11:11It's like everything's so strange. It's all different here.
00:11:15And the kind of thing that he could do was to wake up in the morning and tell his engineer, Irv,
00:11:31Irv, I don't think we ought to be here.
00:11:35Because when you first wake up in the morning, are you ready to slide down the fire pole and set off for the biggest conflagration in the city's history?
00:11:48Well, I'll tell you what, traveling in this job and being in different time zones and testing bikes,
00:11:54just showing up in Catalonia to ride a Suzuki Hayabusa at the original press launch.
00:11:58You wake up in the morning and you're in a different time zone.
00:12:00You're really tired and you're like, I don't feel that happy right now.
00:12:05I mean, I don't know what it's like to show up for a world championship.
00:12:09But when you got to show up and do the job, sometimes you got to really overcome that morning feeling, especially in a different time zone.
00:12:16So they would start talking about gear ratios or about tire choice.
00:12:20And little by little, everything would normalize.
00:12:25And then Freddy would go out and do magnificent, brilliant things.
00:12:32And this was not the result of some high-level analysis.
00:12:42Because when people would say, well, what about turn seven?
00:12:46He would put his hands up to the imaginary handlebars and get that puzzled look.
00:12:54And you could tell that he forgot to check.
00:13:00Because he was doing it as things came at him, he handled it.
00:13:09And usually with tremendous brilliance.
00:13:14And of course, I like to say that the top rider in a given era is the one who best implements the value of the technological solutions that are new.
00:13:35And we know that Kenny, for example, knew that motorcycles turn badly but accelerate wonderfully.
00:13:44So his corner strategy was to get the turning that the motorcycle doesn't do all that well, get it done quickly at an early apex.
00:13:55Get it turned and shoot it out of there.
00:13:58Acceleration, emphasis on acceleration.
00:14:01And Freddy, you can't tell if he said to himself, well, if I go into the corner a little faster and the front end starts to wash out, what if I go in faster yet?
00:14:18And, well, naturally the answer is, you'll fall down.
00:14:23Your helmet will fill up with gravel as you slide to a stop.
00:14:27But he had worked this out on a couple of dirt tracks in Kentucky as a younger man, as a lad actually.
00:14:38And what he'd found was that if you went in faster than the speed that would wash out the front, and then you gave a little whiff of throttle,
00:14:50the overloaded front tire would be pulled back up the curve, the load versus grip curve, to the peak and you'd go around the corner.
00:15:02And if you listened for this, you could hear it.
00:15:08There's a great photo of Freddy at Suzuka with a black line coming off of his front tire with the bike.
00:15:14I believe it's Suzuka, a black line coming off the front tire.
00:15:19And he could just kind of do that over and over, it seemed like.
00:15:23Yeah.
00:15:25And, of course, this was a tremendous asset.
00:15:29But, again, you had to trust this because it wasn't going to be like a cooperative analytical effort, as it is with some riders, because Freddy was going to solve the problems as they came.
00:15:53And, of course, in 1984, when they started with the NSR 500, the one with the fuel hanging underneath the engine, Michelin were making slick tires.
00:16:09And so Freddy's bike was a test vehicle for the slick tire revolution.
00:16:20And this, the radial ply revolution, pardon me.
00:16:27And so this was an additional complication because he was brilliantly able to sense what the motorcycle was going to do next.
00:16:40And this is something that every rider requires, because if you randomize the motorcycle, you're going to slow down until you feel like it's not going to hurt you.
00:16:51And that's what most riders do.
00:16:54We're sensible people who know that we're not Freddy.
00:16:59And so we don't want to have to cope with things that are new to us.
00:17:05So we ride sanely and sensibly.
00:17:07And Freddy had found that he could cope with these things.
00:17:13And he rode as if he expected to.
00:17:17So the three-cylinder wasn't going anywhere with respect to power because it was about developed out at the end of 83.
00:17:32And there had been discussion about what would be done for 84.
00:17:37Would they build an updated three-cylinder?
00:17:40Would they take advantage of the rules which allowed four cylinders?
00:17:45How would it go?
00:17:47And they decided to do this major pioneering in the form of putting the gas underneath and the pipes over the top.
00:17:56And that was a mistake.
00:17:59But mistakes teach you so much.
00:18:03And shortly after that mistake, all the manufacturers seemed to have bought rigs for testing the polar moments of various things.
00:18:18Whole motorcycles, just the wheels.
00:18:22I remember seeing those apparatus at Eric's place, Eric Buell.
00:18:31Of course, he was terribly interested in those variables.
00:18:35Anyway, they finally decided that they would build a four-cylinder.
00:18:41And as soon as the updates for the three-cylinder that were intended for 84 were finished,
00:18:48they built a single-cylinder test engine, 54 by 54 and a half millimeters, and started testing.
00:18:57And when 84 season began, the motorcycle wasn't terribly powerful.
00:19:07In the early testing, they had found that the three-cylinder had higher top speed, but the four-cylinder accelerated better.
00:19:14And there was a lot of intensive cylinder development going on.
00:19:20And that's probably why the exhaust pipes tended to stay the same.
00:19:25It's because they had a lot of catching up to do.
00:19:29And those cylinders had a center divider exhaust port that was T-shaped.
00:19:37Wide at the top, narrow at the bottom.
00:19:40The idea being to have a lot of area through which the cylinder pressure could leave the cylinder very quickly,
00:19:49so that then they could get on to opening the transfers and starting to refill the cylinder.
00:19:55And Yamaha eventually switched to this T-port, but it wasn't without trouble.
00:20:01And lots of people out there have had the experience of having the exhaust port divider leave a black streak on the piston.
00:20:13Well, what if I drill little holes in the piston?
00:20:16Some mixture will come out through those holes and lubricate that divider.
00:20:20Well, it helped a little bit.
00:20:22How about if we take a rubber wheel and kind of relieve the divider a little bit to lower it?
00:20:27Well, that helped more.
00:20:30And when the piston closes that huge wide exhaust port, it gets a bit of a slam.
00:20:41And the piston is hot, so the material is softened.
00:20:47And so what would happen is that the top edge of the upper ring land would be forged down over the ring and trap it in its groove so it stopped sealing.
00:20:57So that meant before you could fit new pistons, you had to take your trusty triangular file and bevel the edges, particularly the top edge of the single piston ring groove,
00:21:11so there was no material to be forged onto the piston ring.
00:21:16And all this preparation was handwork.
00:21:22It didn't come in the little box from the manufacturer.
00:21:27So it had that old-timey quality, the same as back in the two-stroke days.
00:21:34On any night at the paddock, you could hear the whine of die grinders as people were doing final detailing on a fresh set of cylinders before putting them on their engine.
00:21:44So, 1984 was a learning year, and Freddie was not champion. That was Lawson's year.
00:21:54And this was because of all the stuff that Honda had to collect information about, digest, and decide how they would treat it.
00:22:07And what this all amounts to, I'm not going to bore you with a lengthy, and then they did this, and then they did that.
00:22:17I just got to point out, Kevin does notes for these podcasts. We talk about it, and then he runs off and does his thing.
00:22:25And he's got a career full of notes dating back to almost anything, three-by-five cards, a lot of that going on.
00:22:31The notes that he produced for this podcast were 17 pages. It's amazing. It's got highlights. It's so good.
00:22:44We could do a week-long podcast on this motor and the NSR alone.
00:22:50What came about was that Honda had to deal with Wayne Raney at a point, and Yamaha at this time were very strong in torque.
00:23:09Whereas the Honda was being made to turn pretty high revs, like 12,000 or 12,500, and it had a high top speed.
00:23:24And the engineers were very nervous about, they felt that the crankshaft should be as light as possible because the crankshaft mass can reduce top speed.
00:23:37And the various riders, Freddy originally, and then others, found that the bike pushed the front.
00:23:50And they said, we think the engine should be forward.
00:23:54And the engineer said, oh, we can't do that because you put too much weight on the front and the steering gets heavy.
00:24:01And it turned out that what was going on was all these companies have a program of moving engineers around from one job to another.
00:24:11And they feel that this is desirable because it gives a good overview of what the company's activities are.
00:24:19But in this case, it brought people from production side to the race team where their prejudice against weight on the front wheel conflicted with the rider's need for the front wheel to stay on the ground rather than constantly popping up and being light in corners.
00:24:38When you're trying to accelerate off a corner and the front wheel goes light, you see riders come in after that with making that gesture showing that the front end has closed.
00:24:53They're having to steer in more and more, trying to increase the bite.
00:24:57Then it lets go and the bars turn in.
00:25:02So they managed to get the engineers to trust them.
00:25:07They moved the engine forward a couple of times.
00:25:09The Honda engineers were getting it, sort of.
00:25:16But a big fly in the ointment, of course, was Wayne Ramey and the solid torque of the Yamaha.
00:25:28They used to talk in those days of there being Honda lanes at faster racetracks, where I think Mr. Ito on the fuel-injected variant of the NSR500 achieved 200 miles per hour.
00:25:50But, of course, races are not won by top speed.
00:25:55They're won by acceleration off of corners.
00:25:58It took time for the company and its decision-making apparatus to get the message from the riders, from the trackside people, as to what they really needed.
00:26:19This is often a problem in any type of undertaking like this.
00:26:27For example, pilots versus aircraft engineers.
00:26:31The aircraft engineers aren't up there struggling with pitch instability.
00:26:36All they see is drawing lines on graph paper.
00:26:41This process took a while.
00:26:45Wayne was a powerful force, winning several championships.
00:26:53Lawson managed to win on Honda in 1989.
00:26:59He wanted the chassis stiffer, and they kept on asking for this.
00:27:06Please, we would like.
00:27:09Eventually, they said, how about this?
00:27:12They gave them a chassis that had essentially doubled chassis beams on the side.
00:27:18It was stiff enough.
00:27:21There were several kinds of swing arms.
00:27:25There were the swing arms that consisted of a conventional swing arm with a bracing made of tubing welded onto the top or bottom.
00:27:32Then there was the solid type, which is what you see in MotoGP now.
00:27:38The whole thing is a sheet metal structure.
00:27:42You can't see through it from the sides.
00:27:45A lot of this stuff was being created for the first time out of the conditions of trying to deal with that tough guy, Wayne Raney.
00:27:59There came the unfortunate day when he was injured.
00:28:07Mick Doohan wasn't doing so well, so there was an interregnum.
00:28:15That was the year 1993 when Kevin Schwartz was champion on Suzuki.
00:28:21The big news in terms of technology in that period was a big bang firing order.
00:28:30Honda had started out with 90 degree firing order, so that every 90 degrees, one cylinder would fire.
00:28:41The power delivery to the rear wheel was thus very smooth.
00:28:45But that didn't impress the rear tire.
00:28:50It sounds good intuitively though.
00:28:52It does.
00:28:54Tires like smoothness.
00:28:56They like constant load.
00:28:58They don't want a lot of yanking and hammering.
00:29:01The engineers were just puzzled when the rider said,
00:29:11if we're coming off the corner with a Yamaha guy, the Yamaha guy can start throttling up before us.
00:29:20If we try to throttle up with them, we slide out.
00:29:23How can this be?
00:29:26Somehow, a trial was made with an NSR250, which at the time was a V-twin.
00:29:37They tried a close firing order.
00:29:43They found some benefit, so they built a 180 degree engine.
00:29:51That was better.
00:29:54Now they had parity with the Yamaha guys.
00:29:58They could accelerate with them off of corners, but people were still scratching their heads over.
00:30:04How does the rear tire know when the cylinders that are all putting out the same size bangs, when they're firing?
00:30:15Honda did a bunch of really exhaustive testing because this looked like the beginning of a solid seam of gold in this mine.
00:30:29They just started digging like crazy.
00:30:32They tried all kinds of stuff.
00:30:34What they found was a sweet spot at 67 or 68 degrees.
00:30:41Two cylinders fire, then say 67 degrees later, the other two cylinders fire, so it goes kabang.
00:30:51Then there's a pause of 290 something degrees.
00:30:58This thing was phenomenal.
00:31:01It improved grip during acceleration off of corners.
00:31:06That was so tremendous that the other manufacturers, nobody asked any questions.
00:31:14Nobody said anything about Yamaha way, do it.
00:31:18They all began to sound like 500 motocross bikes.
00:31:23They were deep and grunty.
00:31:27They began to break clutch baskets.
00:31:30They began to break gears.
00:31:32Everybody had to hurry and reinforce all those parts.
00:31:36Of course, what was happening was we all know that if you've got a big crate to move across the shop, you got to have four or five guys to get the thing moving.
00:31:48Then a couple of them can step away once it's moving because sliding friction is less than static friction.
00:31:57Did that exact thing with my mill.
00:31:59I bought a mill.
00:32:01I got it off the lift and into my garage.
00:32:03Three of us, I got this really thick, heavy duty neighbor to come over, football type.
00:32:09Heavy duty neighbor, yes.
00:32:11I'm ready to help him push the mill across.
00:32:15We go, and we get the thing moving.
00:32:18He just takes off all by himself, just slides up.
00:32:21It was an index.
00:32:23It was a 54-inch index mill.
00:32:25Index was a, I think, Michigan manufacturer.
00:32:28It weighed 2,500 pounds.
00:32:30Once we got it moving, he just put it right where it was supposed to be.
00:32:34It was magnificent.
00:32:36Wonderful.
00:32:37What they found was that in lower gears, the bike rolls forward about a full footprint during that 293 degrees of quiet time when no cylinder is firing.
00:32:55During that time, the fresh footprint is laid down without the engine yanking on it.
00:33:04That allows it to recover something like static friction.
00:33:10Whatever it is, the rubber bulging down into the profile, the texture of the surface, the roadway surface, or the formation of little molecular bonds.
00:33:25Whatever it is, the more time you give it, the stronger the static friction effect.
00:33:32Then you unleash those four cylinders over 68 degrees, and they give a god-awful yank on that well-planted footprint.
00:33:44Your bike is hurled forward in a satisfying manner.
00:33:49Rinse and repeat?
00:33:51Yes, just so.
00:33:53That's an example of Honda's resources enabling them to say, I want you to find out about this.
00:34:06This looks promising.
00:34:08Just put a bunch of engineers on it, assign some budget, and go do it.
00:34:13Never mind the fact that at the moment, when the Japanese manufacturers are doing well to get a bike into the top 10, it's not working like that right now.
00:34:26But organizations, they're not easy to deal with.
00:34:30At that time, the reputation was always Honda Technology.
00:34:35They were always, at least externally, they certainly appeared to be investing more in exploring many, many ideas.
00:34:43As you said, Mr. Oguma, his refrigerator, correct?
00:34:46Yes.
00:34:48They would research something and say, this could be useful in the future.
00:34:51They'd just throw it in the fridge and pull it out when the time came to make a meal with it.
00:34:55It seemed to be that Honda was able or had put more money into doing that.
00:35:06Indeed, they burned.
00:35:08Of course, they tried that gas tank under the engine thing.
00:35:15It didn't work out, but they tried it.
00:35:18Nobody else ever tried it again since then.
00:35:22What this all came down to was, after they had made the breakthrough with the Big Bang, and another breakthrough that they had made was made in a very traditional way.
00:35:43When a new model comes to the racing department, it has been designed by engineers with degrees from Tokyo University.
00:35:55Basically, what it is, it extends with a dotted line performance trends that were proved in the previous season.
00:36:04We're going to make it.
00:36:06It was good.
00:36:08Now, we're going to make it better.
00:36:10They wheel that thing into this shop where there are these two guys.
00:36:16One of them was known as Lobster Man.
00:36:19I tried to find out who he was when I was in HRC in 2020, but it was a head scratcher.
00:36:28Oh, we don't know.
00:36:30These two men had the responsibility for getting the horsepower out of the new design.
00:36:38They had a modular exhaust pipe system by which they could quickly rough out how long the header should be, how long the horn, how long the center section, and so forth.
00:36:53Then, when they brought in the welders and the sheet metal rollers, they could get the fine details right.
00:37:02The center section may need to be three millimeters longer or shorter than that in order to really make the mountain peaks coincide, so you get a tremendously strong effect.
00:37:14Those men discovered something that Yamaha was working on very tentatively in 1978, which was to turn the second set of transfers, the so-called B transfers.
00:37:30The A's are the ones that are on either side of the exhaust port.
00:37:34To swing those things, what seemed like backwards in terms of intuition, point them toward the exhaust port.
00:37:46What that seems to have done is to allow the five streams entering the cylinder to crash one another into a lower energy state, so that instead of a single jet of fresh mixture going up the non-exhaust cylinder wall across the cylinder head,
00:38:16and down to the exhaust port in the twinkling of an eye, resulting in a power band that you can't even get through sideways, it produced a cylinder-filling generosity.
00:38:32It was quite wonderful.
00:38:35I made a conversion for a TZ750 employing this idea.
00:38:43I might modestly say a couple of years before Honda did it, but it worked so well.
00:38:54Those men must have felt pretty jolly when they came up with this, because it was worth about between two and four horsepower per cylinder.
00:39:06It got them from wherever they were to something more like 160 horsepower for the whole engine.
00:39:15These men were experienced, but they also knew that trial and error requires the ability, like a good salesman.
00:39:30The salesman goes to nine doors and they all slam in his face.
00:39:35He's got to go to the tenth door with the same cheerful attitude and sell the daylights out of that Encyclopedia Britannica.
00:39:44Those men were busy this whole time.
00:39:48Years this took.
00:39:50When they finally had their motorcycle emerged and Mick Doon had a period that was pretty much clear of the injuries that he was vulnerable to, he put together five years of solid success.
00:40:09So solid that someone in some publication said, why doesn't he slow down and make a race of it?
00:40:20What had happened then was that they had a reliable engine.
00:40:28They knew how to make the kind of power that Doon could accept.
00:40:34Doon, for his part, said, I am here only to win races, not to test engineers' ideas.
00:40:44He was known to say when he was told, okay, we've got a different front end on this bike for first practice, take it off.
00:40:53I'm not riding it with that thing on there, because I'll waste the whole practice trying to figure out what that different front end is telling me.
00:41:02And if it doesn't tell me accurately, I'm going to hurt myself.
00:41:07Then where will we be?
00:41:09So he constantly tried to make the motorcycle more rideable.
00:41:14And quite often, the changes required for that reduced the top speed.
00:41:21So he would have a dominant lap time and an indifferent top speed.
00:41:28Repeating the great lesson in racing, which is top speed, we pay attention to it because it's a big, impressive number.
00:41:38But you only get to use it on that one or possibly two straightaways.
00:41:44Whereas there are 12 or 14 or however many corners off of which you must accelerate.
00:41:51And if you have smooth power, controllable power, and power that's wide enough that you don't have to shift gear in the middle of a critical operation, you're going to leave the others behind.
00:42:09Now, you mentioned ATAC.
00:42:13ATAC was a resonance chamber up near the exhaust port with a valve.
00:42:22And it could turn the exhaust pipe from this frequency to this frequency and add about 500 RPM below the normal torque threshold.
00:42:38So that was useful because it meant less shifting, less upset for the tire, more like what Doohan wanted.
00:42:49They came up with another wonderful, well, no, wait a minute.
00:42:52The ATAC was used for several years, and then they finally switched to Yamaha way, which was a variable height exhaust port that opened at different heights, depending on how the gates were raised and lowered.
00:43:13And if you've seen Kawasaki motocrossers, you'll know that they had a divided exhaust port and the gates were quite complicated.
00:43:24And Honda had to deal with problems associated with extra heat affecting the cylinder, probably distorting it and causing leakage.
00:43:35But that's just engineering, more testing.
00:43:39And the variable height exhaust port broadened the power band even more.
00:43:46And that was used right to the end.
00:43:50At one point, maybe it was 96, the engineers came with water injection.
00:43:57Well, the resonance of the organ pipe, namely the exhaust pipes on the engine, one for each cylinder, depends on the velocity of sound in the pipe.
00:44:10So if the gas is very hot, the pipe resonates at a higher frequency.
00:44:16But if you can cool the gas, it will resonate at a lower frequency, so they thought.
00:44:21Let's spray water into the header pipes.
00:44:25And see what that does.
00:44:27Well, it allowed the engine to pull from 6,000, which otherwise is just like, are you kidding?
00:44:35Because what happens with these 500cc doesn't sound big, but it was big in those days.
00:44:44When a big two-stroke hits its torque threshold, torque typically doubles.
00:44:54Which means, wham, on the ground, if you're working the tire hard at that point.
00:44:59It's hard to communicate what a two-stroke, a non-ATAC, non-variable exhaust port, just a straight up, we need to make power here.
00:45:10The way that it would come on, like in an RD350, TZ350, 250, where it just shoots up.
00:45:19It's that Schwantz roll, right?
00:45:21Revs are rising, and we're rolling as it's coming up.
00:45:26We're closing the throttle to try and keep the output in a linear manner.
00:45:31It's just, it's insane.
00:45:33So having that flexibility as a rider, for somebody of Doohan's magnitudinal talent, is what a weapon it would become to have that flexibility.
00:45:47So, eventually, he was injured again, and he decided, okay, that's enough racing.
00:45:55And, like Kenny said years before, he said, racing, typically, a good rider has 10 years at the top.
00:46:08He said, it's like something is used up, and when it's gone, there's no point in continuing.
00:46:14So, Doohan bowed out, Alex Crevier took one more championship on the NSR.
00:46:23Then he ran into health problems.
00:46:26The year that he won, this brash kid, Valentino Rossi, had his learning year on the bike.
00:46:36And he said later, Alex wanted the powered-up version of the engine, and he said, you can do one fast lap on this engine, but 24 laps are another story.
00:46:53So, Crevier was out of the system, and Valentino Rossi won his first 500cc world championship on the NSR.
00:47:04So, and of course, Kenny Jr. was in there somewhere.
00:47:11The NSR went to the museum then, because it was like the development of aviation during wartime.
00:47:22The development has to go on, while the combat is at its most intense.
00:47:28You have to go on, and you have to go on, and you have to go on, and you have to go on.
00:47:34The development has to go on, while the combat is at its most intense.
00:47:40You have to provide adequate reliability, even though you don't know whether the power increase that you're hoping to fly to Europe in three weeks is going to be equally reliable.
00:47:53And it's probably a good idea if we all work through the night on this one.
00:47:58And so, it was really a classic story.
00:48:04Trying A, trying B, and as they got a better grasp of what was required, the motorcycle began to be this beautiful work of art.
00:48:18Those close-ups, side views with the fairing off of NSR 500s are framing quality.
00:48:29I wish I had one on the wall right here, because they had an engineer whose whole duty was to make the individual parts look as though they had been produced by the immortal gods.
00:48:48So that when the members of the other teams looked upon them, their hearts would sink, and they would think, why don't we just go home?
00:49:01And I hope that that particular engineer is enjoying a pleasant retirement, because he did things like the following.
00:49:12When you pull the clutch or the brake lever, the end normally bears on the exposed end of the hydraulic piston that produces the pressure in the line.
00:49:25Oh, we can't have that. We must have a roller on the end of the brake lever.
00:49:31A roller? Yes, a needle bearing. Let's put a needle bearing in there.
00:49:37But Greg will get in. No, we'll have a seal, one on each side.
00:49:43So all these part numbers. Ah, what a smooth pull.
00:49:49I think it was Peter Egan said that about a Honda. I think it was a VFR 750 he was writing about, and he said that Hondas feel like they have little bearings inside of every pivot, and in that case they did.
00:50:04Yeah. So they eventually produced a motorcycle which remained essentially static during the 90s.
00:50:19In the early 90s, the FIM said, now we're going to low lead fuel as a sort of the beginning of the lead removal process.
00:50:30Now, tetraethyl lead is dreadfully poisonous, but it is also a potent anti-NOx catalyst.
00:50:40What's happening to produce NOx is that a chemical fragment known as the free radical, OH-, oxygen, hydrogen, with a negative charge, is produced by the pre-flame reactions when you get unburned mixture really hot, up over 900 degrees.
00:51:05And when the population of these OH- guys are in there, like troublemakers in a bar, guys that are getting restless, then you need the anti-NOx catalyst tetraethyl lead, which basically suppresses.
00:51:22It turns the production of OH- down so that instead of the population rapidly increasing and resulting in NOx, hold off a minute, not just now.
00:51:37And there are a lot of cases like this in which something that's tremendously effective, hooker chemical was well-respected for some of their products before they became famous or infamous in the case of the, oh, what was the name of that dreadful?
00:51:58Love Canal, the Love Canal disaster.
00:52:03But they were just, they were following their industry standard.
00:52:06So tetraethyl lead had to be removed because exhaust catalysts were coming in and lead liked to occupy all the sites and turn the catalyst off so that it couldn't do its job of completing the combustion of unburned fuel.
00:52:24Anyway, then at the end of the 90s, no lead fuel came in.
00:52:31So they were having to deal with these changes at the same time as they were providing McDooan with a nearly constant motorcycle whose communication with him was not being interfered with by novelties from the engineering department.
00:52:56And this is a wonderful example of what can happen when there is such good cooperation between an outstanding writer and the people who are supporting him in the field.
00:53:11So I was surprised when I went to the Motegi Museum in 2020, I'd never been there before.
00:53:20And there was a late model NSR over by a window and I went to look and reading the provided material and I'm looking at the engine.
00:53:30Oh, crankcases are water cooled.
00:53:34Nice one.
00:53:36Because here comes the mixture.
00:53:40Fuel is spraying in the carburetors, four of them.
00:53:47And the evaporation of the fuel is cooling the intake flow.
00:53:52But now it's flowing into a hot crankcase.
00:53:56Air temperature up, up.
00:53:58Now it's going up through the transfers and into the even hotter cylinder.
00:54:02Now here comes a piston that's pretty hot, compressing it up against a cylinder head that's also hot.
00:54:12So when they got rid of the lead, they had to do things like make the cylinder cap out of high conductivity copper.
00:54:22And they had to, Yamaha did anyway, they increased the thickness of the pistons to nearly half an inch to provide a good heat pathway from the center of the piston dome, which is the hottest place, outward to the cooler cylinder wall.
00:54:41And cooler it was because all these two strokes were running hot bath water coolant temperature, like 135 Fahrenheit.
00:54:52You wouldn't want to be in that water, but it's a far cry from the 190 that we expect from production stuff.
00:55:02The whole idea there was to keep the crankcases as cool as possible and the cylinder, especially around the exhaust port, so that the fresh charge coming in did not get too far in the direction of detonation.
00:55:19As its temperature rose and the production of OH minus, those naughty boys, increased.
00:55:28And nothing works better than tetrathyl lead, right? That's kind of our number one anti-knot compound.
00:55:34Well, they were very thorough. This was in the early twenties. And I think Delco employed an engineer whose name will come to me presently.
00:55:49And they said, sort this out. And he had dozens of test engines running constantly, and they were testing one compound after another.
00:56:03And they found that there were some iron compounds that were promising and they found that there were manganese compounds.
00:56:10But the one that really did the job was lead tetrathyl, which unfortunately is hideously poisonous.
00:56:18I discovered that when a friend of mine worked at a chemical company and I was struggling with British cars, getting good octane and getting anti-knock and being able to get the performance out of them.
00:56:32And he worked for a chemical company. I said, well, can I just get some to add to my own fuel?
00:56:39And he's like, oh yeah, I'll look into that. And it's like, oh my God, no, the drums are on scales.
00:56:45It's heavily, heavily regulated and it's fantastically toxic. You don't want that. You don't even want it.
00:56:52We all have dreams.
00:56:54A similar material used to be used. What was it? It's a mercury compound. Dimethylmercury was used as a standard for the maximum toxicity and they had to stop using it because a drop on your skin kills you.
00:57:14It just kills you. And there's no point in, you know, it's like, well, geez, dad, been great knowing you.
00:57:25And I can't say I'll see you later.
00:57:28So lead is gone, but the fuel that they brought immediately when the lead ban took effect had, they called it a chemistry set fuel.
00:57:43It had five elements in it, not elements, five compounds.
00:57:48There was the four good octane structures, octane just means eight carbons.
00:57:56It had triptane, it had toluene, it had MTBE.
00:58:03And so that the engine would cold start, it had isopentane.
00:58:09Isopentane has an anti-knock rating of about 91.
00:58:16So it's not, it's no mystery cure for anything.
00:58:21It's just, it's very volatile, volatile enough to make your engine cold start.
00:58:25So those five things were the initial recipe for making lead-free fuel.
00:58:32And after that, the FIM kept dicking with it and turn it into something that costs like a cocktail in New York City.
00:58:41So that chapter came to an end in 2001 and the following year, MotoGP began.
00:58:52For a short time, if you were in the MotoGP paddock, you could go down to the end for a smoke.
00:58:59Because all the 125s and 250s, which were still two strokes, were down there.
00:59:03They're warming up, you can...
00:59:07Get a whiff of the past.
00:59:10Yes, and change happens.
00:59:15There are ways that two strokes can be made to pass emissions laws, but it is not economically advisable.
00:59:24Because what all the motorcycle manufacturers did, rather than heroically saying two strokes forever.
00:59:33Is that they said, let the automakers develop the emissions control technology.
00:59:41And then we'll go down to the Napa store and get it.
00:59:44And ask them for a discount, will you?
00:59:50And that's the way it's been.
00:59:52The automakers developed all of that stuff.
00:59:54The engine crawling with black hoses, all of which were cracking and leaking.
00:59:581977, stutter and stall.
01:00:02And now we have emerged onto the sunny uplands of digital fuel injection.
01:00:09And cars just start and run and so do motorbikes.
01:00:14And they perform well.
01:00:16Because it turned out that time that all those elements.
01:00:22Digital fuel injection.
01:00:24Fuel worse than the Army Air Corps was burning in 1935.
01:00:30And computing technology.
01:00:34It all went together gloriously.
01:00:37And produced the well-running bikes and cars and light trucks of the present moment.
01:00:44Well, it's crazy.
01:00:46Because you can go pull one of these test bikes out of here.
01:00:49Like a new MT-07 or an MT-09 Yamaha.
01:00:52And get it out in the parking lot.
01:00:56Thumb the starter button.
01:00:58Runs perfectly.
01:01:00It's ice cold.
01:01:02Or as cold as ambient.
01:01:04And then you could do a wheelie.
01:01:06You could throw the clutch and just wheelie out of the parking lot with a cold engine.
01:01:10And it won't even tell you.
01:01:12It's crazy.
01:01:14It knows how to do it.
01:01:16It's so good.
01:01:18It's just remarkable.
01:01:20One thing I wanted.
01:01:22We're getting close to time.
01:01:24And I hope this isn't too big of a question to tackle.
01:01:26But it seemed like everyone ended up with the 54 by 54.5.
01:01:31As the cylinder that they just used.
01:01:33They used it in 125.
01:01:35And then they just put two of them together for 250 and then 500s.
01:01:38Yes, they did.
01:01:39And Yamaha started out with two bore and stroke arrangements.
01:01:44One was 54 by 54.
01:01:46And the other one was 56 by 50.
01:01:48And of course, when it became important to be 249 rather than 248 point something.
01:01:55They added fractions to the stroke.
01:01:58But the basic fact is.
01:02:01We're all conditioned to think that larger bore and shorter stroke is higher performance.
01:02:07That is four stroke thinking.
01:02:09And it is appropriate there.
01:02:11Because the short stroke allows for a given RPM.
01:02:16A reduction of piston acceleration.
01:02:19Which helps reliability or allows you to run up to higher RPM for higher performance.
01:02:26And the larger bore provides room for the big valves.
01:02:33That can fill and empty the cylinder at the higher speed.
01:02:36That is the higher RPM that's made possible by the shorter stroke.
01:02:42So yes, for four stroke, big bore, short stroke is the direction of higher performance.
01:02:49But with a two stroke, the ports are in the cylinder wall.
01:02:54And it turns out that by making the stroke longer.
01:03:00You make the ports bigger.
01:03:03And it's not a night and day effect.
01:03:08But they all tried 56 by 50.
01:03:13And ended up at the end of the two stroke era at 54 by 54.5.
01:03:23Honda did try an engine that was like 50.5 by 60.
01:03:30In looking to take advantage of the larger port areas.
01:03:36And they did some testing with it.
01:03:38And they didn't go forward with that idea.
01:03:41But they did the due diligence.
01:03:44And I think one of the engines that was limited by too big a bore and too short a stroke.
01:03:52Was Yamaha's TZ350 and the RD350 on the production side.
01:03:57Because it was 64 millimeter bore by 54 millimeter stroke.
01:04:04And they thought they were doing good in Grand Prix racing.
01:04:10To get 80 horsepower from that thing.
01:04:13And by 1994, ten years after the 350 class ended.
01:04:19Honda sometime during that year, I think, achieved 100 horsepower from a 250.
01:04:29So, of course, there was a lot of technology.
01:04:33Which had it been applied to the 350 twin.
01:04:38Such as taking the two cylinder bores and swinging them apart.
01:04:42So that those cup handle transfer ports.
01:04:46Transfer ducts could be used.
01:04:48Where the ones that are crammed tightly between the cylinders go up.
01:04:53And then have to make a sudden right angle turn to enter the cylinder.
01:04:59That was a built in two thirds throttle.
01:05:02Which is why 80 horsepower was about it for that engine.
01:05:06But when they had the choice.
01:05:11Two stroke people went for equal bore and stroke.
01:05:14Two bore and stroke is the best compromise between piston stress and port area.
01:05:21Excellent.
01:05:24At least that's as far as our thinking got by that time.
01:05:29Yeah, and then we moved away to 990s.
01:05:33Indeed.
01:05:35That's something else entirely. 990s, 800s.
01:05:38Slowly sinking down. Oops.
01:05:41Yes.
01:05:43That often happens though.
01:05:46The formula has changed.
01:05:48They state an ambition for the formula.
01:05:51And it turns out to be something entirely different.
01:05:54Because everything is changing all the time.
01:05:57For example, there is a piston material.
01:06:00That's twice as strong as the current 2618.
01:06:04All those forging alloys that are derived from Y alloy from 1916.
01:06:11It's aluminum reinforced with tiny fibers.
01:06:19Tiny ceramic pieces.
01:06:22And it's expensive to make at present.
01:06:26But you can be sure that if it was essential for somebody's war effort.
01:06:30They'd find a way to bring the price down.
01:06:33So, no telling what four strokes could do.
01:06:36If that piston material became widely available at a reasonable price.
01:06:43This is the kind of thing that happens in engineering.
01:06:47It's just when you think things.
01:06:49Oh, I've got a grip on this.
01:06:51Something changes and it's all different.
01:06:54Got to think again.
01:06:57All right. Well, thank you for listening, folks.
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01:07:31Yes, indeed.