- 17 hours ago
MOTORCYCLE GEARBOXES EXPLAINED: Shifting, gear mesh, forks and more.
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00:00:00Welcome to the Psycho World Podcast. I'm always tempted to do radio voice and really throw it out there and
00:00:04get the welcome.
00:00:06Welcome to the Psycho World Podcast.
00:00:09Yes, but we'll just carry on. As per usual, I'm Mark Hoyer, the Editor-in-Chief.
00:00:15I'm with Kevin Cameron, our Technical Editor. Thanks for joining us.
00:00:18The topic this week is gearboxes. How does a gearbox work? Why do we have a gearbox?
00:00:23We'll answer some fundamental questions and we'll talk about maybe some things to help them work better.
00:00:29Obviously, the gearbox is critical. We want you to learn how to do stuff, but this is down to you,
00:00:36folks.
00:00:36You take your gearbox apart, it's down to you.
00:00:38We're going to try to help people understand and give you some tools to move forward on your own
00:00:43to figure out how to fix your gearbox and get the most out of it if you want to do
00:00:47that.
00:00:48Otherwise, it'll be an informative program, as usual. Kevin has spent many, many times, well, hours and many times inside
00:00:56gearboxes.
00:00:57And in fact, you've talked about visiting a factory where the guy showed you the factory gearbox
00:01:04and we improved shifting by doing X. And you're like, hey, great. So did I.
00:01:08Okay. In 1972 with Mike Kawasaki. Before we get going on the podcast, we would like to invite you to
00:01:17see us on Patreon.
00:01:19We're doing everything on Patreon will be commercial free. So all of our normal Wednesdays, we'll continue doing this on
00:01:25YouTube.
00:01:26Those will be as per usual with advertising, etc. But on Patreon, you can get this podcast and others without
00:01:34commercial breaks.
00:01:34In addition to the fact that we are putting extra content up. So Kevin and I are joining more times
00:01:40per week and we're getting some short topics in.
00:01:43So we'll have shorter conversations. There's one called The Excellence of Butter.
00:01:47And don't worry, it's related to motorsports and it's also related to staying alive and enjoying a good meal.
00:01:55If you want to figure out how we make gravy, we might even broach that subject in that podcast.
00:02:01Short form. Short form. Shorter form. They're still long. We're still conversing quite a bit.
00:02:06So join us on Patreon. There's a link in the description.
00:02:09And if you subscribe with us over there, it'll be commercial free.
00:02:13And we appreciate any support you got. And thank you.
00:02:16So let's talk about the gearbox, Kevin.
00:02:19Let's do.
00:02:21Why?
00:02:23Why indeed?
00:02:23Why do we need a gearbox?
00:02:26And of course, by comparison with many electric vehicles, battery driven, the electric motor is either connected to the wheel
00:02:40or wheels by through a reduction ratio, which is constant in most cases.
00:02:47Or in the case of hub motors, the electric motor drives the wheels directly and there can be a motor
00:02:55in every wheel.
00:02:56A little bit of a hit on unsprung weight there, but.
00:02:59Well, there is there is a hit.
00:03:01And Ferdinand Porsche back in the days of even before World War One, he had a lot of knowledge about
00:03:12electrical systems and he built a road train, which was electrically powered with hub motors on every car in the
00:03:24train.
00:03:24And there was a power car at the head, which had a powerful engine, IC engine driving a generator.
00:03:33And from the generator flowed the electricity to drive all the wheels.
00:03:37And that constant ratio is not practical for all but the but the lowest powered, slowest of vehicles, mopeds, the
00:03:54most basic kind.
00:03:55And because the range of the engine, RPM range of the engine is much less wide than the speed range
00:04:08of the vehicle.
00:04:11Now, in the case of a moped has an automatic clutch, you turn the grip, the engine speeds up, it
00:04:21carries you away, you pick your feet up and put them on the pedals.
00:04:27And up to about 25 miles an hour, the engine just drives the thing and at 25 miles an hour,
00:04:33it's at its peak power and away you hum to work in downtown Paris, perhaps.
00:04:40And, but the problem is, comes when engine power increases and so does top speed.
00:04:51Because if we build a stronger engine and we gear it directly to the rear wheel, in the early days
00:05:02it was a belt, great big things, flapping, lovely leather, I'm sure.
00:05:08And we do the ratio so that the top speed that is made possible by the greater power we've built
00:05:19into the engine, then the engine has trouble at low speeds because it's fallen below its zone of best torque.
00:05:30And it's kind of ka-chunk, ka-chunk, ka-chunk.
00:05:33So we say, okay, here's what we'll do.
00:05:38We'll add a second speed.
00:05:41The one ratio will be for road cruising and top speed.
00:05:47And the other ratio will be for starting from rest and accelerating until when we shift to the second speed,
00:05:56the RPM of the engine doesn't fall so far that it's going.
00:06:02Quick sidebar, quick sidebar, Suzuki Hayabusa.
00:06:08I did the math and also experimented on the road, you know, 100, 100 pound feet of torque on that
00:06:13rear wheel on our dyno.
00:06:15And you could use third gear on a Hayabusa from about 18 to 20 miles an hour, and it would
00:06:26pull until about 145, as I recall.
00:06:29Yes.
00:06:30Good range.
00:06:31So pretty tractable, pretty wonderfully tractable engine and gargantuan amounts of torque.
00:06:37And if you did some clutch slipping, it was not inconceivable to pull away smoothly in third gear on a
00:06:43Hayabusa.
00:06:43In 1911, Indian, which was manufactured down here in Springfield to the south of me, brought two-speed race bikes
00:06:58to the Isle of Man, and they swept the event, one, two, three.
00:07:02And they had two-speed gearboxes.
00:07:06So the engines they brought were very tractable, and the first ratio was for the lower speed parts of the
00:07:15course, and the higher ratio was for the higher speed parts.
00:07:18But now we increase engine power again, and top speed rises, but the ability of the engine to start from
00:07:32rest may not.
00:07:37So now we need an intermediate speed between the two, because what we don't want is when we shift out
00:07:45of our first ratio to our top ratio, that the engine RPM has been pulled down so far that we
00:07:52have chain snatch.
00:07:56And, or we've pulled the engine down into an RPM range where its torque is too weak to continue the
00:08:03acceleration, which would be like, well, you could try it by shifting, engaging only three speeds.
00:08:15Anyway, they added the intermediate speed between first and top to give a three-speed gearbox.
00:08:22And this is where American motorcycles stayed for years for special reasons, because American oil fields were generous, and they
00:08:35were abundant.
00:08:37And this meant that gasoline was not terribly expensive.
00:08:41It didn't have to be important.
00:08:43So motorcycles were given great big engines that had a mile-wide pulling range.
00:08:49These were literally tractor-like engines.
00:08:53Three speeds were plenty for those things.
00:08:58But in petroleum-free Europe and in England, do you ever remember seeing photos of oil derricks in England?
00:09:11The more they tuned up engines to allow smaller displacement engines, which are more economical, using less of the expensive
00:09:22imported gasoline,
00:09:25the narrower the range of the engine became, because they were having to make use of RPM-sensitive tuning methods.
00:09:34The basic one is to extend camshaft timing.
00:09:39But when you do that, the power range tends to narrow.
00:09:44You are boosting cylinder filling at higher RPM by borrowing from bottom end and somewhat from mid-range.
00:09:56Because if the cam timing is long enough to fill the cylinders at maximum RPM, then at lower speeds, the
00:10:04piston rises on compression.
00:10:06Oh, the intake valve is still open.
00:10:09Oops.
00:10:10And whoosh, part of the charge that you just pulled into the cylinder gets blown out.
00:10:15So that's how hotter cam timing results in weak mid-range and possibly non-existent bottom end.
00:10:26So, three speeds were it in Europe until around 1930.
00:10:34There had been some four speeds built for racing and for production bikes.
00:10:40There were a few production bikes with four speeds.
00:10:42But when they got to the point of racing at the Isle of Man, three speeds didn't do it anymore.
00:10:55After they had got their engines tuned up and they saw the direction in which things were going.
00:11:03For example, megaphones, tuned length intake and exhaust pipes.
00:11:10Now, the reason that the two-stroke engine has such a narrow range is that the exhaust pipe is a
00:11:19resonant duct.
00:11:21There are waves bouncing back and forth inside that thing and as well as smoke.
00:11:26And the range over which they help your engine is maybe 1,200 RPM wide.
00:11:36So, as engines were tuned up to produce more and more power but over a narrow range, bear in mind
00:11:47that the most popular displacement in Europe and England, as Harley executives found on their 1924 fact-finding trip, was
00:11:57350 cc's.
00:12:00Whereas in the U.S., a thousand cc's was normal.
00:12:04So, a third the displacement.
00:12:06So, they're having to get whatever power it is that they need to get around out of this little engine.
00:12:12So, they're going to have to push the compression ratio.
00:12:16Compression helps torque at all speeds.
00:12:20They're going to push the valve timing, which tends to raise, push the power toward the top of the RPM
00:12:27range.
00:12:27They're going to use the tuning effects of pipes, exhaust and intake.
00:12:34These operate only over a few hundred RPM.
00:12:38So, again, if you're trying to get more out of less displacement, you're going to push the torque and the
00:12:48power up towards higher revolutions.
00:12:51So, they added a fourth gear.
00:12:56So, through the 1930s and into the 50s, British racing motorcycles and production bikes had four-speed transmissions.
00:13:12But then came the war, which meant everyone stopped racing, start thinking about making parts for Hurricanes and Blenheims and
00:13:25Lancaster bombers and what have you for the duration.
00:13:30And when the racing business started after the war and the whole motorcycle industry in Britain and in the United
00:13:39States began to produce motorcycles again, not military ones at that, four speeds was the norm.
00:13:51So, all those British parallel twins that came into the U.S. in the 1950s were four-speeds.
00:14:00And they would stay that way until early 70s when five-speeds came in.
00:14:07So, again, there's this speed effect.
00:14:14As you increase the top speed, the RPM of the engine is farther away at top speed from the RPM
00:14:28at which you can pull away in your lowest gear.
00:14:30So, what's happening is that first, the whole gearbox is being re-geared to serve the higher top speed.
00:14:39And now there's a gap between what you'd like to pull away from rest and what you have.
00:14:47So, for street bikes, RD350's first gear was a starting gear.
00:14:54It was so far below second gear that you almost never used it in just riding around.
00:15:01It was just for starting that uphill stoplight with your girlfriend on the back.
00:15:09Very tedious.
00:15:11So, the low starting gear.
00:15:14And also in the 1950s, two-strokes were getting developed.
00:15:21In the spring of 1951, here comes Erich Worf, an engineer at DKW in Germany,
00:15:30inventing a very modern-looking two-stroke expansion chamber, which has two tapers.
00:15:41It tapers out like a megaphone.
00:15:44There's a center section that is cylindrical.
00:15:46And then there is a tapering back down, which the Germans called Gagenkonus, the countercone,
00:15:54which reflects a pressure wave back to the cylinder, any fresh charge that has looped around the cylinder
00:16:04and gone out the exhaust port.
00:16:06Ah, freedom!
00:16:08Oh, here comes the pressure wave.
00:16:12Pushes it back into the cylinder.
00:16:14What began to happen is those engineers realized we have the beginnings of an acoustic supercharger,
00:16:22which uses exhaust energy to supercharge the engine through the exhaust port.
00:16:31Well, when they started making real power with two-strokes, that is, 20 horsepower from a 125,
00:16:41which was about equal to what the four-strokes were making in the late 50s, 125s,
00:16:49they found that the more power they made tended to make the power band absolutely disappear.
00:16:59So they added more gearbox speeds until finally there was one 50cc racer that had a dual-range transmission,
00:17:10three times, two times nine, three times six, 18 speeds.
00:17:15It had three ranges and six speeds.
00:17:21So can you imagine rowing your way through that thing?
00:17:25Suzuki's little 17,500 RPM 50 had 14 speeds.
00:17:31Its gearbox shafts were so long that they had to have support bearings in the middle so they didn't sag.
00:17:38So this whole thing with gearbox ratios had become ridiculous.
00:17:51And even the four-strokes.
00:17:54Even the lowly Honda Trail 90.
00:17:57I had a 1969 Honda Trail 90.
00:18:00It had a dual-range gearbox.
00:18:02And I took it off-road.
00:18:03I did 100 miles off-road one day on that thing and dirt roads up in the mountains here.
00:18:09And I was riding the regular range.
00:18:11And I thought, well, this is perfectly fine.
00:18:13You know, I don't need this low range.
00:18:15It seems redundant.
00:18:16And I got to a sandy, kind of bumpy uphill.
00:18:19And I was struggling to get up.
00:18:20And I said, well, this is probably a good time to try this thing.
00:18:23And I shifted.
00:18:24There's a lever on the box.
00:18:25And you shifted to low range.
00:18:27And I got back on.
00:18:28And I couldn't believe how great it was.
00:18:30It was a real difference.
00:18:32It was really good.
00:18:33So I guess I don't even remember.
00:18:36I think that's a four-speed.
00:18:37So I would have had an eight-speed.
00:18:38Not that you would use them, you know, in the way that you described in the racing motorcycle.
00:18:46But highly useful.
00:18:47It was good.
00:18:48Yes.
00:18:49Charming.
00:18:49Charming.
00:18:50The four-strokes were getting up there.
00:18:54Seven, eight, nine, ten speeds.
00:18:58More speeds for the smaller, screechier engines.
00:19:01Like the 21,500 RPM, 50 cc of 1965.
00:19:09So all the Japanese companies quit racing in 1967.
00:19:16I think Yamaha continued with their factory stuff for a year.
00:19:20But basically, the big four stopped.
00:19:24And the FIM, the sanctioning body, said,
00:19:31who's going to use a 14-speed gearbox that he made in his cellar?
00:19:37Maybe nobody.
00:19:39Maybe one or two very clever Dutchmen who have an extreme desire to make fast 50s.
00:19:47But here's what we're going to do.
00:19:49We're going to limit the number of gearbox speeds to six.
00:19:55And they limited the number of cylinders for 500 and 350 to four.
00:20:02And for the 250 and 350 to two cylinders.
00:20:08And for the 50 cc to one cylinder.
00:20:11So suddenly, well, we learned how to make power when we knew we had this fantastic gearbox
00:20:19that weighs more than the engine.
00:20:20What are we going to do now?
00:20:23Get busy widening the torque curve of your engine.
00:20:29And at this point, the advantages of four valves over two consist in terms of performance
00:20:39that four valves don't need to be open as long
00:20:44because they have more curtain area as they open.
00:20:51The exposed flow area is the lift of the valve, how far it is off its seat,
00:20:56times the distance around the two valves in the case of a four valve.
00:21:02And allowing a shorter timing means that you don't have to have cam timings such as I described
00:21:10that are so long that they only work on top end because at lower speeds.
00:21:15They're pushing the mixture out of the cylinder through this late intake closing.
00:21:24Okay.
00:21:26The four strokes have been taken care of.
00:21:29Four valves are going to broaden their range so that they're going to do just fine
00:21:34with six speeds.
00:21:39And the two strokes, they began to play with just how far they could push the port timing
00:21:51and still get the benefit of exhaust waves.
00:21:56And they found that there, at that time, it was like there was limitless power.
00:22:00Every year, they could add five more horsepower.
00:22:03And that's what happened in racing in 1975.
00:22:07All Grand Prix classes were won by two strokes.
00:22:10And it stayed that way until 2002 when MotoGP began.
00:22:18But six speeds.
00:22:20And even today, that remains the rule.
00:22:23Now, let's think about what happens when a MotoGP bike whose top speed is 225 miles per hour
00:22:32and it has a fairly close ratio gearbox, that gearbox set of ratios is moved over
00:22:39so the top gear is 225 miles per hour.
00:22:43Bottom gear is 112 and a half miles per hour.
00:22:49What?
00:22:52So, this brings us to tricks that have been used to make six speeds into a workable situation.
00:23:05The cassette gearbox.
00:23:08A cassette gearbox is a system in which if you take off the clutch and the clutch cover
00:23:15and undo the screws around the plate that has the two gearbox shafts in it,
00:23:21you can pull that thing out of the motor in one unit.
00:23:27And you can change the individual gear ratios.
00:23:31If your rider is saying, I don't know, man, turn five, I'm just hanging there.
00:23:36And I need another 300 revs to get the engine pulling.
00:23:42No problem.
00:23:43We put in a ratio that does that for you and set the previous ratio aside.
00:23:49At MV, who always raced four strokes after 1950,
00:23:58they had in the race shop, they had a big board, which was like three feet square with pegs in
00:24:05it.
00:24:06Peg, peg, peg, peg, peg, peg, peg, rows and rows of pegs.
00:24:08And on every peg was a stack of gears.
00:24:13And these were their alternate ratios.
00:24:16So that, and they, of course, there was a wonderful book of useful information
00:24:22that told you which ratios for which racetrack.
00:24:27And so that was a dodge that allowed them to tailor the gearbox to the circuit,
00:24:33thus making it possible to have six speeds and not fall off the bottom or suffer some other.
00:24:41That's almost a podcast in itself, Kevin.
00:24:43It is.
00:24:44The application of ratios to different racetracks.
00:24:47And you're running out of revs between corners because you're trying to get a drive.
00:24:50And the straight's just a little too long, but you're losing time if you shift.
00:24:54Yes.
00:24:55It's really, it's a lot of complicated math.
00:24:58I suppose analytics now with everybody having data acquisition
00:25:04that they can somehow calculate the ratios a lot easier.
00:25:09I can't imagine that.
00:25:10I can't imagine it's much of a challenge these days.
00:25:12The one thing that you must observe is rev drops at upshift because in order to make your bike pull
00:25:22in the next higher gear, the rev drop must not pull it down to a RPM at which the engine
00:25:31can't accelerate the bike.
00:25:34And that's why those first gears on RD350s and other bikes of that kind, without big displacement
00:25:43to drag the bike away, no matter what the ratio, what you'll find if you write down the ratios
00:25:52and figure out what the RPM drops are from first to second, second to third, and so forth,
00:25:57you'll find the rev drops get smaller as you go up the gearbox.
00:26:02Why?
00:26:02At the top of the gearbox, most of the engine's power is overcoming aerodynamic drag.
00:26:09So you don't want the RPM to fall very far for that fifth to sixth upshift because the engine
00:26:15might just go, boh, I can't pull that wide.
00:26:22So they make the rev drops large at the bottom where it's easy to accelerate the motorcycle.
00:26:30The air drag is practically zipped and there's not a lot of energy in the motorcycle at 25 miles an
00:26:35hour.
00:26:36So they're wide at the bottom and they get narrower and narrower and narrower toward the top.
00:26:41Yeah, that's why your one-two shift is so clunky sometimes.
00:26:44The relative speed of the ratios is quite wide.
00:26:47It is.
00:26:48And so when you shift the dogs into the next one, it's a pretty good clunk.
00:26:53And it's one of the reasons that on the Honda Goldwing DCT, the dual clutch automatic is they added another
00:27:01ratio.
00:27:01So the first gear and the sixth gear are the same as the manual Honda Goldwing,
00:27:05but they added a ratio for one, two, and three to narrow those gaps to smooth that response.
00:27:12So you have a seven speed since we're not racing Goldwings.
00:27:14We should, I guess, but we're not.
00:27:18And I heard years ago that this might not be true today,
00:27:23but the lap record for Goldwing around Willow was faster than that of a major U.S. manufacturer's, any motorcycle
00:27:34that it made for production.
00:27:41Now, Goldwing, that's a special thing.
00:27:45Anyway.
00:27:46Well, it is.
00:27:46I mean, the Goldwing, just to give props to Honda on the flat six, it makes about 100 to 108
00:27:52foot-pounds.
00:27:53It makes about, I think it's 100 foot-pounds at 1,000 RPM.
00:27:56Oh, I thought it was 12 RPM.
00:27:58I knew it was low.
00:28:00Well, the peak, the torque peak, the 108 is something like 1,200.
00:28:07And then it just tapers off after that.
00:28:09And that was an intentional tuning.
00:28:10But it doesn't taper a lot.
00:28:11It just keeps on holding that chain.
00:28:12It breathes well.
00:28:14Yeah, it's remarkable.
00:28:17Shaft drive.
00:28:18What's wrong with that?
00:28:18Shaft drive, yeah.
00:28:20Well, now imagine Bonneville.
00:28:22You've built a motorcycle that's geared for 400 miles an hour.
00:28:25How do you start from rest?
00:28:27You don't.
00:28:28Traditionally, a souped-up pickup truck with boards bolted to the front of it pushes you up to a speed
00:28:36where you can get going in wherever your lowest gear is.
00:28:42But there have been some mishaps because at low speed, streamliners are not terribly stable.
00:28:51The intentions of the driver of the streamliner and those of the driver of the souped-up pickup truck may
00:28:59differ from time to time.
00:29:01So, there's been a move to build 8-speed special, 8-speed transmissions for streamliners so that they can start
00:29:11from rest.
00:29:12They have the little training wheels that come down.
00:29:16They close the lid.
00:29:18The thing is going raccada, raccada, and away it glides.
00:29:24So, another thing that is related to rev drop from gear to gear is gearbox range, which is dividing top
00:29:37gear into first gear.
00:29:40On a trial spike, that might be 3.25 because a trial spike has to be able to authoritatively climb
00:29:49up one side of a boulder.
00:29:52But they do the most amazing things on trial spikes, and they need that low-down grunt.
00:29:59If you want to see somebody, go look up Tony Bowe, B-O-U.
00:30:03If you haven't followed trials, just what Kevin said is so profoundly true, Tony Bowe, T-O-N-I-B
00:30:10-O-U, look him up.
00:30:11He's remained on the top of that game for a long time, and it is unbelievable what he does.
00:30:18Sorry, but we have to get across there.
00:30:21It seems like the rubber used in such machines is actively glue.
00:30:29Anyway, because they do such fabulous things.
00:30:34So, gearbox range, trials bike, 3.25.
00:30:37Lower power street bikes, somewhere from 3 to 2.6 because they have to have that lower gear to start
00:30:49from the uphill stoplight with a passenger.
00:30:53And powerful sport bikes may have as little as 2.25.
00:31:05And 2.25 is what the TZ 750 had.
00:31:08It had to have a somewhat wider range than the usual 2.0, which for years and years was the
00:31:18thing that road race bikes had,
00:31:20because it had a very high top speed for its time, 180, 185 miles per hour.
00:31:30So, that meant that the range of the gearbox had to be stretched a bit because of the broader range
00:31:39of speeds that the motorcycle could reach.
00:31:43Then there are the special needs motorcycles, the heavy tour bikes.
00:31:49They need, first of all, the lovely bottom torque that Mark just talked about.
00:31:55I think 80% of peak torque is available at 8.50 on that gold wing.
00:32:038.50.
00:32:09And so, they need a low first for making a dignified exit.
00:32:16You don't want to be fussing with the clutch and slipping the clutch and all that nonsense.
00:32:25So, we have a low first.
00:32:27Then we have a range of four speeds in the middle that will handle the hills and dales of doing
00:32:36a 1,000-mile day.
00:32:39And for the straight and four-lane part of your day, we have an overdrive sixth, which pulls engine RPM
00:32:49down so that the soles of your feet,
00:32:55the ischial region of our posterior, and our hands don't feel such vibration that they feel a bit sleepy.
00:33:06And so, that's a special kind of gearbox.
00:33:13It's notable that all modern gearboxes, with few exceptions, are indirect.
00:33:23British transmissions, older transmissions, were the clutch drove one shaft, and the output sprocket driving the rear wheel was on
00:33:38the same axis.
00:33:40Sometimes behind the clutch.
00:33:43Sometimes in front of the clutch, depending on how the designer had drawn it.
00:33:46Don't even make me save Elisette.
00:33:48But I won't make you.
00:33:51I'll just allude to it.
00:33:53We know.
00:33:56And the power comes in on one shaft.
00:33:59It goes to a counter shaft in all gears except top, in which the output sprocket is locked to the
00:34:08clutch shaft.
00:34:09So, you have one-to-one there.
00:34:11But in an all-indirect gearbox of six-speed, there are six pairs, six on each shaft.
00:34:18And they are selected by shift forks, which are moved by some form of cam plate or cam slotted shift
00:34:30drum.
00:34:31Shift drums are the most common now.
00:34:34So, that's what the basic gearbox type is today, except for the DCT.
00:34:51And DCTs are a little bit different.
00:34:56There are people who just cannot allow themselves to enjoy something that could be better than the traditional four, five,
00:35:08six speeds.
00:35:09Because a real motorcycle has a clutch, it has a throttle, and there's nothing automatic about it.
00:35:17It is under your control.
00:35:21Before the motorcycle, people rode horses.
00:35:24And the horse has something that no motorcycle has, its own opinion.
00:35:30And so, there's a policy, there's politics between the rider and the horse, which fortunately, motorcyclists don't have to endure
00:35:40or master to the degree possible.
00:35:44So, those constant mash pairs are engaged to a splined shaft.
00:35:58Here's a splined shaft.
00:36:02And here is a gear with visible splines in it.
00:36:10And on either side of a gear that has splines may be gears that are free-spinning on the shaft.
00:36:18And when you wish to engage one of the free-spinning gears, it is one or the other gears is
00:36:30moved along the shaft to engage these big pegs that are on the face of the gear.
00:36:39And they correspond with big pegs on the adjacent gear.
00:36:43So, when you shift, you're moving.
00:36:46This gear has a shift fork groove in it that allows it to be moved while it's spinning, moved axially
00:36:55along the shaft.
00:36:56So, the clunk, it locks itself to the adjacent gear, which is then, through the splines in this gear, locked
00:37:05to the shaft.
00:37:06While the mate to this splined gear is a free-spinning gear, so that a double engagement is not possible.
00:37:16Unless something very bad.
00:37:19Yeah, just as a note, you really want to do everything you can to avoid a double engagement, which is
00:37:24why it's so sensitive working on a gearbox.
00:37:26It's got to be, everything's got to be just right.
00:37:30And, of course, our experience is that once it is just right, gearboxes run for a long time.
00:37:38It's not like they are hidden crocodiles with only their nostrils showing that are waiting to rise up and do
00:37:48something unpleasant.
00:37:49Well, there is a lot of mysticism in the gearbox.
00:37:52And there is a lot of, like with anything, there's a lot of attention to detail.
00:37:57You're holding up gear dogs, and there's three gear dogs there, and some of them have more.
00:38:03But three is pretty common.
00:38:05But the shape of those gearbox will be different on a sporting motorcycle because we want them to suck into
00:38:13each other and to be incredibly positive with no shift rejections under great duress.
00:38:19And then you also want, that would cause a lot of, yeah.
00:38:23If anyone can see this, but these pegs are slightly undercut.
00:38:28The engaging surfaces have been milled at an angle.
00:38:33It's like a trapezoid, basically, so that the edges are turned this way.
00:38:39Once they catch, there is a force tending to draw them together into full engagement.
00:38:45And that's called undercut.
00:38:49So, a lot of street bikes don't have any undercut.
00:38:53They work perfectly well.
00:38:55As long as you aren't trying to do shaky things.
00:39:03British bikes had cam plates, which was a plate that was moved by a ratchet mechanism controlled by your foot
00:39:11on the lever.
00:39:13Dating back to 1927, when Harold Willis at Veleset came up with this system that we use now, where between
00:39:24shifts, the shift pedal goes back to its normal position.
00:39:29It doesn't go first, second, third.
00:39:32And you can imagine the cramping of your leg muscles as you try to make something like that work.
00:39:39Yeah, tank shifts were like that.
00:39:42You had your big, you know, let your clutch out.
00:39:46Or you'd have a foot clutch, and you'd let your clutch out and ride away.
00:39:49And then first was up here, and you'd pull it, click, and the second.
00:39:52And there's a big chrome thing with teeth on it and notches.
00:39:55And you'd, there's second.
00:39:57The gate.
00:39:58That's the gate.
00:39:59The gate shifter, yes.
00:40:00So, you know, it's a fun operation.
00:40:03I mean, I'm tired of the shifter returning to the center.
00:40:07And, in fact, I'm tired of MotoGP riders not needing to pull a clutch or do anything like that at
00:40:12all.
00:40:12It's annoying.
00:40:13I think we should go back to tank shift and give them something to do.
00:40:15That's a real motorcycle.
00:40:16That's a real rider.
00:40:18Yes.
00:40:19I love the concept that they don't have enough to do.
00:40:23Hobbies.
00:40:23I like hobbies.
00:40:24And my hobby is setting magneto timing and shimming ancient gearbox gears and smelling the chlorinates in the gearbox oil
00:40:34and all that.
00:40:35That's my hobby.
00:40:37Practicing to become a little pervert.
00:40:38When I go racing, yeah.
00:40:40When I go racing, I want the, I want a perfect gearbox.
00:40:45I love seamless shifting.
00:40:47I'm not, no.
00:40:48I love quick shifting, up and down.
00:40:50When I'm trying to set a lap time, that's great.
00:40:52I love riding, racing a vintage bike.
00:40:55Up shifts, down shifts, using the clutch.
00:40:57You blow that one.
00:40:58And it's pretty bad.
00:41:00But we practice a lot.
00:41:01We like it.
00:41:02But I want to go faster.
00:41:04And that's where we get M1000RRs with quick shifters.
00:41:07It's nice.
00:41:12Well, should we move on to common gearbox problems?
00:41:17Well, I wanted to talk about ratios that, you know, in a perfect world, we'd pick perfect ratios for our
00:41:22application and everything would be wonderful.
00:41:25But there are some exceptions to that.
00:41:28And one of those is noise regulations.
00:41:30So if you take a dual sport bike, some of the dual sport bikes have ratios that are chosen to
00:41:36lower the RPM at the speed of the ride-by test so that the motorcycle passes the sound check.
00:41:42And so one example that pops to mind is the Honda XR650L.
00:41:48And it's got a gap.
00:41:50And the second gear ratio, as I recall, is the one that, you know, we have a, we're pulling the
00:41:55RPM down pretty hard.
00:41:57So if you're gearing that for off-road, you can sort of gear it to use second.
00:42:03But what you do is you pick the off-road gearbox, you pick the old XR ratios and drop them
00:42:08in.
00:42:09And then you have ratios that don't have to pass the sound check, right?
00:42:13And that's how we do that.
00:42:14So there's just a few exceptions there.
00:42:16Sometimes you pick, you know, as you said, on a touring bike, you pick your sixth gear as a nice
00:42:22overdrive.
00:42:23So you just lope into the torque and you're just kind of chuffed down the road on a Harley.
00:42:29You know, you have a rubber-mounted, on the touring models, you have a rubber-mounted V-Twin of great
00:42:33displacement and much inertia and mass, probably 40 pounds of flywheel and a pretty tall sixth.
00:42:41There's, I think, one thing we haven't talked about is, it's a detail, but there are helically cut gears and
00:42:47then there are straight-cut gears.
00:42:49These are straight-cut.
00:42:52And that's a great, strong, also can make some noise.
00:42:57And that was the thing that Harley did.
00:42:58It was, yes, because as one tooth gives up the load and the next tooth takes it up, the teeth
00:43:07bend and unbend.
00:43:08A little bit more wind.
00:43:10They can be pretty darn quiet.
00:43:12If the clearances are really nice, you can make that pretty quiet.
00:43:15Yeah, but Harley, in 2009, they made fifth gear a straight-cut gear in their touring models.
00:43:28And the 09 bikes, you shift into fifth and you had a little bit of gear noise.
00:43:32And then by 2010, they had enough people complain, well, this is fifth gear.
00:43:36Something must be wrong with it.
00:43:38That they, because sixth was helically cut.
00:43:41So when you shifted into sixth, it was just quiet city.
00:43:43So the helical is a curve and the way that they engage is more gradual and, I think, tighter.
00:43:50More teeth are in mesh.
00:43:52Yeah.
00:43:53At the same time, which is, it's a way of reducing noise.
00:44:00So you will notice, if you've done any mechanical work at all, you'll notice that primary gears are always helical.
00:44:09Because they're spinning, the pinion is spinning at crank speed.
00:44:16And so, but if there's a sporting version, a race version, it will have straight-cut gears.
00:44:23Because they don't want the side thrust that results from that.
00:44:26And it's just adapting to the requirements of the job at hand.
00:44:38One final thing is final drive.
00:44:41If you make your final drive taller, the space between the ratios mathematically gets farther.
00:44:48And if you make it shorter, then you effectively mathematically have a shorter, a closer ratio gearbox.
00:44:55Is that true, Kevin?
00:45:00I haven't thought about that one.
00:45:02I did the math.
00:45:03I did the math.
00:45:04I did the math because I was interested in changing final drive and what would happen.
00:45:10I think as a service, before we move on to common gearbox problems, we're going to ask Kevin to write
00:45:17down a few gearbox math tools.
00:45:22And he's going to send them over and we're going to, we're going to put them down in the description.
00:45:26So we're going to have an information block that says here, please use this math.
00:45:30Calculate, find the ratios of your motorcycle and calculate the top and bottom, the spacing.
00:45:36And then look at the ratios and calculate what would happen if you change from a 17 to an 18
00:45:44front.
00:45:45And look at the mathematical change that one tooth at the front makes versus one tooth at the rear, two
00:45:51teeth at the rear.
00:45:52Play with that and understand that.
00:45:54And you will see a whole new world of understanding of what you might try to achieve with your XS
00:46:00-650 all the way up to your Yamaha YZF R1.
00:46:03Oh, here's another curiosity.
00:46:07Back in the late eighties, people figured out that what riders were complaining about on corner exit was that the
00:46:24back of the motorcycle was squatting down and taking weight off the front and pushing the front end.
00:46:32And so we, you know, we know that cars squat down when they accelerate because the force accelerating the car
00:46:41exists at ground level and the mass of the car behaves as if it is at the center of mass,
00:46:47which is above.
00:46:48So there is a torque being exerted that tends to take weight off the front and put more weight on
00:46:55the back.
00:46:59And this effect, pushing the front, is bad, don't want.
00:47:10So what they realized is that if they got the angle of the chain to the plane of the swing
00:47:18arm just right, the tangent force generated by the chain would cancel the squat force generated by acceleration and the
00:47:30motorcycle would no longer squat and push.
00:47:35Well, once they got that angle right.
00:47:39There was a temptation to say, well, let's not change the gear ratios ever because we got it good now.
00:47:45We don't want it.
00:47:46What did they do?
00:47:48They have gear cutting machines at the factory.
00:47:52They cut new primary gears.
00:47:54Yeah.
00:47:55So rather than changing the final drive, which is going to change the angle of the chain ever so slightly
00:47:59because you're changing the tangent of the force.
00:48:04Oh, the final drive and chain pull is a podcast.
00:48:08I think we've certainly touched on it many times, but I think it did exist as its own podcast because
00:48:15I was just thinking about shaft drive racing motorcycles, such as ones that I've raced, like a BMW 75.
00:48:21Yes, roll on, roll off, roll on, roll off.
00:48:25And that's why Dr. John Wittner came up with his parallelogram suspension for Guzzi's that canceled the elevator or, yeah,
00:48:34the elevator ride.
00:48:35Sometimes you'd go up, sometimes you'd go down, depending on are you accelerating or decelerating.
00:48:39So a different kind of force, but a similar effect, harder to get rid of on a shaft drive bike
00:48:44than on a chain drive.
00:48:45So if you look at some super bike regulations, they say no alternate primary ratios will be permitted.
00:48:55Yeah.
00:48:56Well, this was the birth of the adjustable swing arm pivot in usually a homologation special type bike.
00:49:03Like, you know, your ZX-7RRs and all those, they had ride height adjustment and they had a pivot height
00:49:09adjustment where you could change the relationship of the swing arm pivot to where the sprocket is.
00:49:15And there are...
00:49:15It's another way of changing the angle between the drive chain and the central plane of the swing arm.
00:49:22Yeah, there was a period of time...
00:49:24Sorry, go ahead.
00:49:25Finish.
00:49:26Determines.
00:49:26It determines the angle of the chain to the central plane of the swing arm, which determines the lift force
00:49:36that can counter the squat force so that your bike does not squat and push.
00:49:41Back in the old days of TZ750s, which is 50 years ago...
00:49:47What?
00:49:4850 years ago, I watched TZ750s come off of Turn 9 Laguna, as it was then Turn 9.
00:49:58And as the rider got on the gas, they lifted and they topped pretty hard.
00:50:06So those things had...
00:50:08They had thought about it, but it wasn't yet a science.
00:50:12And then in 1988, a Japanese engineer was charged with, improve this chassis.
00:50:21It's lousy.
00:50:23So he decided to get more grip by encouraging weight transfer.
00:50:32And you could see that thing coming off of Turn 11.
00:50:36It would squat down at the back.
00:50:38Yeah, which used to be 9.
00:50:39By this time, it was 11, because we added the infield to slow down that fast left up the hill.
00:50:44It squatted and pushed.
00:50:45So, yes, they got the weight transfer they wanted, but they couldn't get off corners.
00:50:53So they couldn't use that chassis.
00:50:56They had to come up with something else pretty quick.
00:51:00So, looking at common shifting problems, the ones you love to discover are in the external shift linkage,
00:51:12which means you don't have to take anything apart.
00:51:17Look at the linkage as you move the shift pedal to full stroke and see if the linkage in the
00:51:29clevis,
00:51:30some of these systems use clevises, some use heim joints, if it binds somewhere,
00:51:36if it hits the throat of the clevis and resists letting the shift mechanism go to full stroke,
00:51:46either up or down.
00:51:49And very often, people have had shin splints from holding their foot at an unnatural angle,
00:51:58have finally sought relief by adjusting the height of the shift pedal.
00:52:02So, it's possible when you do that to arrange it so that it binds.
00:52:09So, this is the first thing to check.
00:52:11Well, used bikes especially, but even new bikes for setup.
00:52:16Used bikes, you kind of want to make sure you're set on the spline properly.
00:52:22Yep.
00:52:22So that your stuff.
00:52:24The shift shaft spline.
00:52:25Your shift shaft.
00:52:26Everything is arranged in a way that you're getting the range of shifting exactly when you want it
00:52:33in the range of what's happening on the shift drum or cam plate on the inside.
00:52:38With no bind.
00:52:38With no bind.
00:52:40Yeah.
00:52:42Another grim one, potentially grim one,
00:52:46and it's so frustrating when it happens,
00:52:49is can't find neutral.
00:52:53You increase the pressure more, more, more, clunk.
00:52:57It jumps from first to second, straight through neutral.
00:53:01So, then you exert pressure the other way, clunk.
00:53:05It jumps back to first.
00:53:06But it will not stop in the neutral detent,
00:53:09which, by the way, is usually shallower than the other five.
00:53:17Five, and six, seven, pardon me.
00:53:20And so, what's happening here?
00:53:24If there is some clutch slip, for example,
00:53:27maybe your engagement is at a rather low lever position,
00:53:33which means that when you lift the clutch,
00:53:35you're not lifting it as far as if the engagement was farther out.
00:53:40This may be adjusted as simply as just raising the clutch lever,
00:53:47lifting the plates farther apart
00:53:50so that they don't exert this awful pressure dog to dog
00:53:57that is opposing your effort to smoothly move from first to neutral.
00:54:09But it may be that that doesn't fix it.
00:54:13Well, clutch setup is really something.
00:54:14I mean, so I know you're going to get into your clutch plates are warped,
00:54:19and I'll let you do that.
00:54:21But from the very beginning,
00:54:23particularly if you have a cable clutch with an arm,
00:54:26sometimes there is a hash mark,
00:54:28like on a WR250 dual sport bike,
00:54:30which I have replaced the clutch on mine,
00:54:33there's a hash mark and you have to get that hash mark of that lever set properly
00:54:37with the relationship of an adjuster on the clutch push rod
00:54:41that positions its position and it shouldn't be rubbing all the time.
00:54:45There's a lot of detail here that you need to read about
00:54:47and study so that you can have an exceptionally good clutch.
00:54:52So when your motorcycle is running
00:54:54and you're sitting in the parking lot of your driveway
00:54:57and you're in neutral and it's idling and you pull the clutch in
00:55:00and you click into first gear,
00:55:03pay attention to where the clutch engages,
00:55:06how close to the bar.
00:55:07And if it's very close to the bar,
00:55:09look into why that is,
00:55:11because it might not need to be like that.
00:55:13You might get much better engagement,
00:55:14particularly if you're having a hard time finding neutral.
00:55:17And you can adjust that.
00:55:19You can adjust the range
00:55:20and there's all the things through the clutch from the push rod
00:55:23and a little ball or throwout bearing.
00:55:25And then there's usually an adjuster down here on the clutch push rod
00:55:29that then will help the lever arm be in the right position,
00:55:32which then will be in the right position for the clutch pull.
00:55:36On old British bikes, there are two kinds of levers
00:55:39and the offset of the pin to where it picks up the cable is different.
00:55:43And if you mix those up, they're terrible.
00:55:46You get an incredibly hard clutch pull.
00:55:49So these are things that I've learned the hard way.
00:55:52I'm just, I'm not giving you the answer.
00:55:54Or I'm giving you the opportunity to go out and say like,
00:55:57hey, I have this, I have this issue.
00:55:59My clutch is very close to my grip.
00:56:00Or man, my Triumph clutch pull is ridiculously heavy.
00:56:04Why is that?
00:56:04It shouldn't be like that.
00:56:06And then find the answer,
00:56:07go out there and put the light in the dark place.
00:56:11All right, Kevin,
00:56:12tell us about warped clutch plates and stuff.
00:56:15Well, the clutch plates in a modern clutch
00:56:18have separator springs between them,
00:56:21or they may be made out of some synthetic rubber.
00:56:24And the idea is that these separator springs
00:56:27are easily compressed by the clutch springs.
00:56:31So when you release the clutch to drive away,
00:56:36they are not causing clutch slip.
00:56:39They're just strong enough to separate the plates.
00:56:41You hope, fingers crossed.
00:56:44A lot of people have seen a lot of gearboxes
00:56:48where those things were discarded.
00:56:50People didn't want them for whatever reason.
00:56:52But are the separators present?
00:56:56That can be a question.
00:57:01Because there's always the story of the person
00:57:03who, I believe it was a Triumph in this story,
00:57:06an old-time Triumph,
00:57:08the clutch plates sat overnight
00:57:10with the clutch springs squeezing the oil out
00:57:14from between the plates.
00:57:15And the fellow comes out,
00:57:19starts the thing up,
00:57:20and when he tries to put it in first,
00:57:22it stops the engine.
00:57:26Because the clutch does not,
00:57:28break loose.
00:57:29It is glued,
00:57:32fully engaged.
00:57:34And this particular person said,
00:57:36sort of shrugged,
00:57:38pushed off down the hill,
00:57:40clonked it into first,
00:57:42started the thing that way.
00:57:44And once the engine got warm,
00:57:47found that by pulling the clutch in
00:57:48and giving it the gas,
00:57:50that the clutch plates would finally
00:57:53release their fond embrace,
00:57:55and normal functioning would pursue.
00:57:57A virtually non-existent problem
00:57:59on a modern motorcycle.
00:58:01Right.
00:58:01Yes.
00:58:02But this is part of the
00:58:06old curmudgeon
00:58:09problems that fascinate some of us.
00:58:12Oh, it's wonderful.
00:58:14I mean, again, it's a hobby,
00:58:15you know, but if you,
00:58:16if you need to make it to work on time
00:58:18or you pick your kid up at school,
00:58:19you need something that runs.
00:58:20That's the,
00:58:22you know,
00:58:22the stress factor of that,
00:58:24that idea that I'm,
00:58:26it's,
00:58:26it is enticing.
00:58:27It's possibly connected to gambling.
00:58:31Will I make it?
00:58:34Did I set the points just right?
00:58:35Is my clutch set perfectly well?
00:58:38I don't know.
00:58:39Let's find out.
00:58:40That,
00:58:40that is a hobby.
00:58:42And as long as you don't have
00:58:43real life getting in the way,
00:58:45that's why we sell new bikes.
00:58:47Old junk's not for everybody.
00:58:48It's for me.
00:58:49I like playing with it,
00:58:50but I do love a modern bike.
00:58:52You know,
00:58:52you take your 750 Hornet back here.
00:58:54We're not going to be touching that clutch
00:58:56for a long time unless we do
00:58:57really dumb things to it.
00:58:59Starts,
00:59:00runs.
00:59:00That's what we want.
00:59:02So,
00:59:04coning.
00:59:05If,
00:59:06if somebody makes a lot of hot starts,
00:59:09it can be that the steel plates
00:59:13become distorted because the sliding,
00:59:17like with brick discs,
00:59:18the sliding velocity is highest at the
00:59:21outer edge of the clutch disc.
00:59:23And at a minimum,
00:59:24I'm at the inner edge of the friction surface.
00:59:27And what this does is it stretches the disc
00:59:31to a larger size when it's hot.
00:59:34And it permanently stretches the inside part.
00:59:37So when it cools,
00:59:38the only way that it can coexist with itself
00:59:42is to boink,
00:59:44form a very slight cone.
00:59:47And coned plates produce clutch drag that can't be adjusted out.
00:59:56And so this is for the guys who have to make a lot of hot starts
01:00:01in order to feel that serene union with the machine.
01:00:08Can I give a,
01:00:09I want to give a practical field piece,
01:00:11piece of field advice.
01:00:12So I learned this from a drag or learned this from a professional drag
01:00:15racer who did a lot of street bike,
01:00:17like non wheelie bar drag racing,
01:00:19very talented person.
01:00:24And if he did several runs in a row,
01:00:26he would not just park the bike and throw it on the side stand and walk away
01:00:31or throw it in the stand and walk away.
01:00:34You ran the motorcycle with the clutch pulled in.
01:00:36And the reason you did that is the clutch plates were incredibly hot.
01:00:40And by upholding the clutch lever to the bar,
01:00:44while the engine was running,
01:00:45you were circulating the clutch in cooling oil and he would cool off the
01:00:49clutch after a series of runs.
01:00:51And I applied this to dirt bikes because one time was street gearing on my WR
01:00:55two 50 Yamaha,
01:00:57which was not,
01:00:58which is good street gearing,
01:00:59but it's not climb up a vertical hillside.
01:01:02And I was,
01:01:03uh,
01:01:03I should have recommitted and carried more speed.
01:01:06At the bottom of this hill to keep in the range of the gear,
01:01:10the shortest gear that I had,
01:01:11which was a street first before I put the big sprocket on the back.
01:01:16And I slipped the daylights out of that clutch.
01:01:18And when I got to the top of the hill,
01:01:19the engagement of my clutch,
01:01:22when it engaged had changed because I had ground off a lot of friction
01:01:26material to make the hill because I,
01:01:29I didn't turn around and I got to that and I remembered Mr.
01:01:32Drag racer and I knew my clutch had to be smoking hot.
01:01:36So I pulled the clutch in and I held it and I'm sure,
01:01:39or I hope I'd like to believe that I saved my clutch that day.
01:01:43And it,
01:01:44it served me well for a long time before I had to change it.
01:01:47In a way,
01:01:48this,
01:01:48this reminds me of,
01:01:50um,
01:01:52people,
01:01:53turbochargers,
01:01:54of course,
01:01:54run very hot because exhaust gas is passing through them and they have
01:01:59plain bearings for the most part.
01:02:01and,
01:02:02uh,
01:02:03they're lubricated by the engine oil system or by a separate oil system.
01:02:08Some competition people keep the oil circulation going after the engine has
01:02:14been shut down to,
01:02:15to pump that heat out of the turbo so that it doesn't coke the oil and block
01:02:22the circulation.
01:02:23So these are,
01:02:25these are things that,
01:02:26that you can do to cool parts that desperately need it.
01:02:30Like,
01:02:30I mean,
01:02:31in addition to,
01:02:32in addition to being driven by exhaust gas and being very hot,
01:02:36uh,
01:02:36you know,
01:02:37your,
01:02:37your turbo can spin 200,
01:02:39300,000 RPM also in some applications.
01:02:42So lots of,
01:02:44yeah,
01:02:46tiny little Ishii Kawajima Harima turbines.
01:02:50They're,
01:02:50they're marvelous to behold.
01:02:54This tiny thing can turn your anemic motorcycle into a giant of
01:03:00performance.
01:03:01Or it can make your Hayabusa into the most monstrous thing ever.
01:03:04It's yes.
01:03:05A stock Hayabusa is a wonderful experience.
01:03:08And then I wrote a turbo that had 380 horsepower at the,
01:03:13at the wheel,
01:03:15you know,
01:03:15tie down straps on the dyno,
01:03:17like not just the ones holding it down and a chalk,
01:03:20but tie down straps,
01:03:21pulling it to the rear.
01:03:23So that doesn't launch forward so hard.
01:03:26It was really,
01:03:27so I wrote it on the street and I had a night or a,
01:03:29sorry,
01:03:29it had a dual boost button and you,
01:03:31um,
01:03:31it was wired to the horn button.
01:03:33So there was no,
01:03:34it was no horn,
01:03:35but if you really wanted to honk,
01:03:37you held that button in and you got,
01:03:39instead of whatever it was,
01:03:40it was like 12 pounds.
01:03:41You went up to 25 or 27 or something like that.
01:03:45Yes.
01:03:46Spicy goodness.
01:03:47I bet that had a special clutch.
01:03:49Power is proportionate to the mass of fuel being consumed.
01:03:55Well,
01:03:55uh,
01:03:56if,
01:03:57if you have visited race paddocks,
01:03:59and done that walk around possibly with children,
01:04:03you hope to inoculate with their,
01:04:06our strange disease,
01:04:09uh,
01:04:10you have seen motorcycles sitting with their clutches removed and all the
01:04:16clutch plates hanging from the right hand foot peg.
01:04:20If you're doing clutch service,
01:04:22where are you,
01:04:23where else are you going to put the things?
01:04:25Oh,
01:04:26here's,
01:04:26this is the clutch plate bracket.
01:04:30And,
01:04:31uh,
01:04:31that's just one of the things that,
01:04:32that you'll see at racetracks and,
01:04:35uh,
01:04:37race team limits the use of a set of plates to one or two,
01:04:42uh,
01:04:44hot starts.
01:04:45Then the plates are all really replaced.
01:04:49And,
01:04:49um,
01:04:50that's a,
01:04:51one of those realities,
01:04:53the clutch plates become a consumable like Kleenex,
01:04:58even though they cost good money.
01:05:04Well,
01:05:05a district manager told me the following story.
01:05:10He said,
01:05:12all the complaints about clutch slip went back to the warranty departments.
01:05:20And in Japan,
01:05:21they made the grave decision to make a bigger clutch.
01:05:26And when the new model came out with the bigger clutch,
01:05:31the snowfall of warranty reports increased.
01:05:36It did not decrease.
01:05:38And the DM said to me,
01:05:40what we found was happening was that the word got around,
01:05:45Hey,
01:05:45the new models got this great big clutch.
01:05:48Now you can do nine burnouts instead of four.
01:05:52And so they did nine burnouts.
01:05:55Yeah.
01:05:55So this is,
01:05:56this is why it's important for there to be liaison between the user and the
01:06:03manufacturer.
01:06:04Yeah.
01:06:05The best quote I have from a product person at a manufacturer who was
01:06:09launching bikes and getting them out into the field was we can't believe
01:06:13what the consumer can break.
01:06:15Yes.
01:06:16You know,
01:06:16they thought they'd had a really complete test program and they really just,
01:06:19they overbuilt and they did everything they could and then problems.
01:06:24And so it's,
01:06:25uh,
01:06:27yeah,
01:06:27development,
01:06:28you know,
01:06:29testing in the field.
01:06:30Yes.
01:06:30We're all betas,
01:06:31I guess,
01:06:32at the end of the day.
01:06:33For Bigfoot,
01:06:34the,
01:06:35uh,
01:06:35gear stomper,
01:06:36um,
01:06:39how many repair orders are,
01:06:42O's are written.
01:06:43Let's say,
01:06:45uh,
01:06:47hard shifting first to second makes ratcheting sound.
01:06:51Uh,
01:06:53won't go.
01:06:55And what's happening there is that making one after another wide range,
01:07:02first to second shift,
01:07:03considerable speed difference between the gears.
01:07:07Instead of clicking neatly into full engagement,
01:07:12the dogs are glancing off the edges of their engagement surfaces,
01:07:19which are becoming rounded and polished so that when you try to push them
01:07:25together,
01:07:26no,
01:07:26they say knocka,
01:07:28knocka,
01:07:28knocka,
01:07:28the ratcheting sound as they bounce off of each other and refuse to make the second
01:07:33shift.
01:07:37necessary engine out cases split.
01:07:42This is your reward.
01:07:44Now,
01:07:45the people who live for the four o'clock,
01:07:48um,
01:07:49impromptu drag race know this as a fact of life.
01:07:55Every now and then you're going to need new,
01:07:58uh,
01:08:00new gears there.
01:08:01That's just something that that's necessary.
01:08:04Just like the two stroke racer knew that the fresh cylinder that he just laid out good money for is
01:08:10good for 900 miles,
01:08:13maybe nine 50.
01:08:14It's a consumable.
01:08:16Um,
01:08:19so today we have the quick shifter and the quick shifter causes when the,
01:08:26when the shift linkage senses a shift is happening.
01:08:32It sends a signal,
01:08:34which turns off the engine for,
01:08:37uh,
01:08:39six hundredths of a second and just enough to unload the dog so that the shift
01:08:47is more or less effortless and it clunks into the next gear without ratcheting noises.
01:08:58And let's have it.
01:09:00I like it.
01:09:01All the variable shift time on all the electronic stuff now is,
01:09:05is beautiful.
01:09:06It works very much like a semi-automatic.
01:09:10You know,
01:09:10you have to use most of the time you have to use a clutch to leave the line and then
01:09:13the rest of it up and down is,
01:09:14is just shift at will.
01:09:16Pretty much a pretty darn smooth.
01:09:18Not perfect.
01:09:19Uh,
01:09:19DCT is,
01:09:20is great for the,
01:09:22the engagement of the gears are,
01:09:25are instantaneous because it's already engaged.
01:09:28That's how DCT works is there's two,
01:09:30two shafts and it's a purpose built automatic.
01:09:33The automatic on the,
01:09:35like the BMW,
01:09:36um,
01:09:37the automated shift assistant,
01:09:38they call it,
01:09:39automates shifting of a normal manual gearbox.
01:09:43So the clutch has a motor that engages and disengages progressively.
01:09:48And then the,
01:09:48uh,
01:09:49shift drum has a motor that turns it and gets you,
01:09:53uh,
01:09:53gets you through the gears.
01:09:54It works,
01:09:54it works pretty well,
01:09:56but it's variable kill time and it's,
01:09:59um,
01:09:59it's pretty seamless.
01:10:00And they've also moved the sensor,
01:10:02you know,
01:10:02the old time quick shifter way back in the day,
01:10:05you had a dial where you could adjust the kill time and that was just the
01:10:08kill time for every gear.
01:10:09So you're not really worried so much about the one,
01:10:12two shift.
01:10:12You're probably worried about second,
01:10:14third,
01:10:14fourth and getting your quick shift just so for those.
01:10:18And you'd turn your dial on that.
01:10:19And it had an external,
01:10:21uh,
01:10:21like a spring loaded,
01:10:22uh,
01:10:23shift detector and it only worked going up.
01:10:27And,
01:10:27uh,
01:10:28now we have it in both directions and they've moved,
01:10:30many have moved the sensor to inside the gearbox so that it's more
01:10:33accurately feeling what's going on rather than way out on the
01:10:36linkage.
01:10:37Yeah.
01:10:37It's pretty nice.
01:10:39It's good stuff,
01:10:40man.
01:10:40It's,
01:10:42it's,
01:10:42it's,
01:10:42so we have sensors on,
01:10:44we have sensors on everything and it's,
01:10:46it's really,
01:10:47it's been wonderful because they've just found applications for those as
01:10:52as we were more accurately measuring RPM and ambient air temperature and
01:10:56intake air temperature.
01:10:58We human beings are covered with sensors.
01:11:00They're there to warn us,
01:11:03you're damaging yourself.
01:11:04Stop that.
01:11:05That's why it's hurting.
01:11:06You're tired.
01:11:07You should sleep,
01:11:09get something to eat.
01:11:11And so motorcycles,
01:11:12which need protection from Bigfoot,
01:11:16uh,
01:11:17are being,
01:11:18are developing a nervous system.
01:11:21And the brain is the ECU.
01:11:24And this is inevitable.
01:11:26This is not some kind of corrupting influence from,
01:11:30uh,
01:11:32laptops.
01:11:33This is the future of the motorcycle and get used to it.
01:11:39But why not?
01:11:43Sensors became reliable on automobiles.
01:11:47I once talked to a guy who was in the sensor business.
01:11:49He said,
01:11:50call me sometime.
01:11:51I never did.
01:11:52I wish I had,
01:11:54but to make sensors that cost 80 cents to make and $300 to replace,
01:12:00um,
01:12:00is now a well-established art.
01:12:04So shall we leave the internals to a later?
01:12:10discussion.
01:12:10I suppose we should.
01:12:11Yeah,
01:12:11we should do for the laundry list of,
01:12:13of problems.
01:12:14Um,
01:12:15we'll,
01:12:15uh,
01:12:16we'll pick that up.
01:12:17We've.
01:12:18Separately.
01:12:19We've managed to talk enough.
01:12:21Yes,
01:12:21we have.
01:12:24Uh,
01:12:24we hope you got something practical out of this and,
01:12:26uh,
01:12:26and a few little,
01:12:27um,
01:12:28you know,
01:12:28uh,
01:12:29lighted bits to see and understand a bit more what's going on.
01:12:33Um,
01:12:34it's always a pleasure to talk anything with Kevin gearboxes.
01:12:38It's a highlight of my week.
01:12:39We'd love joining,
01:12:40uh,
01:12:41joining you here and you joining us again,
01:12:43check us out on Patreon.
01:12:45Um,
01:12:45if you like what we're doing,
01:12:46share with your friends,
01:12:47we really appreciate it.
01:12:49And this is another edition of the cycle world podcast.
01:12:51Can we do a close and we will catch you next time.
01:12:54We'll see you next time.
01:12:54Yeah.
01:12:55Yeah.
01:12:55You
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