We all want our engines to last forever and run perfectly. What's the best way to break in a motorcycle engine to achieve something near perfection? Cycle World Technical Editor Kevin Cameron and Editor-in-Chief Mark Hoyer talk about engine break-in on this episode of the Cycle World Podcast to share their research and experience about engine break-in and the "13,000 times" Hoyer has removed his Velocette MSS piston. OK, maybe he's not an expert? Find out now...
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Listen on Spotify: https://open.spotify.com/show/6CLI74xvMBFLDOC1tQaCOQ
Read more from Cycle World: https://www.cycleworld.com/
Buy Cycle World Merch: https://teespring.com/stores/cycleworld
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00:00Hi everyone, and welcome back to the CycleWorld podcast. I'm Mark Hoyer, Editor-in-Chief,
00:04and I'm with Kevin Cameron, our long-time legendary technical editor. This week's topic
00:10is engine break-in. Oh boy, engine break-in. Engine broken. We did engine broken last week.
00:17Go check that one out. We talked about how parts fail and so forth, and of course, like
00:22any topic we have, they're all related. Everything's related. This is engine break-in, and it's
00:29always been a much-debated topic. What do you do? How do you break-in? What's the best?
00:36How's my engine going to get the best performance and last forever? We're going to try and help
00:44ourselves understand that and help you understand that and make an informed choice with your
00:50new motorcycle. What do you think, Kevin? Where should we start?
00:56I want to start by saying that engine break-in is the last step of manufacturing, because
01:04in order for lubrication to occur between piston rings and cylinder wall, the cam lobes
01:13and tappets and the bearings, the journals and their shells on the crankshaft, the oil
01:22film thickness has to be greater than the height of the irregularities on the surface.
01:31Engineers like to call those asperities. Yes, asperities.
01:38It used to be, before the 1990s, that the asperity height was fairly high. That's why
01:48in the old days, when you broke in an engine, the oil would be darkened with wear particles,
01:55particularly if your engine did not have a filter. The process of break-in is the process by which
02:04the mating parts wear away the asperities until the asperity height is significantly less than
02:15the lubricant film between those parts. That's what break-in is, conceptually.
02:28Then everything changed in the 1980s when the manufacturers of lubricating oils began to put
02:36in large amounts of anti-wear additive, which these days is generally zinc dialkyl diethyl
02:46phosphate, ZDDP. Back in the 1950s, the hot anti-wear was tricrystal phosphate, which I was
02:57told by a service station attendant stood for TCP, stood for Tomcat piss.
03:07I don't think that's right.
03:10The language is a self-generating collection of ideas. What happened when anti-wear in quantity
03:23was put into lube oils was that the lady who had just bought a nice luxury car takes it to
03:32the dealer and says, this car has been using a quart of oil every few weeks. Shouldn't it have
03:44stopped? No, no, lady, that's normal now. That's the way things are. What was happening was that
03:50her engine was not breaking in. The anti-wear allowed little high spots, little shiny places
03:59to form on the piston rings and other moving parts that were capable of supporting the load.
04:07Then the lubricant film just supported, kept the parts apart from each other, even though
04:15the piston rings were not sealing. Therefore, the engine was using a lot of oil.
04:20This was a crisis for a lot of people who were used to the way things used to break in.
04:30In the old days, the old timers would say, break it in fast, and it'll be fast. Break it in slow,
04:38and it will be slow. Now, the truth in that is that if you do the gentle,
04:46I paid a lot of money for this, and I want it to last, as you said, forever.
04:51Nevermind the fact they're going to unload the thing in a year and get the new hot model.
04:57But that's the feeling that people have.
05:04If you break it in fast, it means that you're using some throttle.
05:10And this is what the piston ring manufacturers tell us we have to do to break in piston rings.
05:18One piston ring engineer told me, 70% of peak load. For short times, high throttle,
05:28not a lot of revs, high throttle equals large load for a few seconds, for example,
05:36accelerating rapidly, followed by a kind of light throttle coasting to allow the wear particles to
05:43be washed away by the lube oil and presented to the oil filter. Well, let's talk about
05:52what we're actually achieving. I mean, break in is most critical in the cylinder bore,
06:00and perhaps second most critical on cam lobes and followers. And sort of the rest would follow
06:08after that. You want everything to get to know itself and to lap itself in, so to speak.
06:13And so let's talk about what you were saying about piston rings and high shiny spots.
06:21My experience with my Velocette, which is a 1954 500cc single 86 millimeter bore, 86 millimeter
06:29stroke. I have had the piston out of that, I don't know, 13,000 times since I've owned it.
06:37Actually, every 2,000 miles, I would say I have about 15,000 to 20,000 miles
06:43of riding on that bike. And until recently, I'd had the piston out every 2,000 miles,
06:49correcting problems, either from rebuild or original manufacture. Now everything's square,
06:55and it's got a custom piston and, you know, a relatively short skirt, not super short skirt,
07:01but it's a Nikasil bore and a new forged piston, a new style forged piston with coatings on it.
07:10And I've run it hard, as you say, and one of the times I took it apart, I noted that the top ring
07:19was completely shiny all the way around. And it's a three ring piston, two compression,
07:23and one oil control. The second ring, which is getting exposed to less pressure from the
07:29combustion chamber, still had a few little shadows on it. It wasn't completely shiny,
07:34it was almost completely shiny. And that's what we're talking about with break-in, is perfectly
07:41fitted rings that mate to the cylinder in the most exquisite way. And so when you're boring
07:48your Velocette, you want to have it in a bore plate that replicates the clamping force
07:52that it would see in service. So that the cylinder bolts, yeah, so that the iron in the
07:59cylinder is distorted or squeezed in the way that it might be in service. And then you put that
08:05finish hone on it. And when you bolt the thing together, and I am a combustion chamber snob
08:11because of that kind of work. I really, really, I, you know, prior to doing that work, the Velocette
08:16oil was dirty in a thousand miles. It was just, it was black, you know, it would be black after
08:22a thousand miles with like my off the shelf piston and an off the shelf iron cylinder bore.
08:26And when I finally had it and I just went full ride, the whole, the oil is like, honey, I could
08:32leave it in for 2000 miles and the color doesn't change. And that is excellent sealing that is
08:38keeping that goal. Yeah. And, and that's break-in that's what we're talking about. And the reason
08:43that the lady in the luxury car was having oil consumption is the rings never found the surface
08:49of the cylinder. They never did that minute lapping minute break-in. Intimate contact. Yeah.
08:58And that's, that's why it's so critical. And so when you say, yeah, I'm going to be really easy
09:03on my engine and try to take, Oh, good, good care of it. And I'm going to, you know, it never,
09:09it never makes the contact that it really needs to become happy and to be, to be good sealing.
09:18So this was complicated a little bit by what happened when the manufacturers began to get
09:26these warranty claims, engine did not break in excess oil consumption, low performance
09:32got, gets their attention. So fortunately the lubricating oil companies either have people who
09:42can read books or there are some older people working there who, who said, well, now this
09:48reminds me of something that happened a long time ago. And what it was the manufacturers of large
09:57aircraft engines were pouring a lot of gasoline through these engines to break them in. And
10:04someone said, can't we do better than this? So also they were having problems with Chrome
10:11plated rings, which were a new thing then new to them anyway not breaking in very hard surface.
10:18It takes a while to file that away. So what they began to do was to, to pre-lap the rings.
10:26They would finish them in a, in a dummy cylinder with a very fine abrasive powder, as you spoke
10:34of earlier before we went on the air here. And those rings would be so close to being right
10:43when the engine started up that it would take much less of the hard running,
10:49light coasting, hard running coasting cycle to make it ready for takeoff.
11:00And they did the same thing with crankshaft bearings. They said, we'll make the crank pins
11:07really smooth and not like shining shoes. We want them to be truly cylindrical so that all parts of
11:15the surface are carrying the load. And that was called the Chrysler super finish process. It was,
11:23I won't go into the details, but the first person to bring that back in America was Junior Johnson,
11:33the former stock car driver, and then an important builder. And he got bothered about
11:41how much oil was flying around inside of his engines and how hot it was getting, and he wanted
11:47less. So he said, why can't I run thinner oil and smaller bearing clearances and get some of that
11:56out of my hair? Well, if you just put thinner oil into an engine that has a sparity height that
12:04sticks up through that oil film and touches the other surface, then you've got
12:12unpleasantness occurring. So they had to come up with finer surface finishes.
12:19And so that's what Detroit did. And that's what the motorcycle manufacturers did.
12:24And I saw this when I rented a car in Atlanta. It had seven miles on it. So before I drove away,
12:33I opened the hood and pulled a dipstick and pure amber oil of great clarity dripped
12:43from the extremity. It was lovely. And so I thought, I'll look at this again after 250 miles
12:51of Atlanta rush hour traffic. So I went about my business. And when I came back to the airport,
12:58I checked a second time. I pulled out the dipstick. Lo and behold, clear amber,
13:06perfect oil, just as you described, once you got your Velocette to seat properly.
13:12See that folks, science happens every day. You just got to look for it.
13:16It's just a name we put on common sense of a fairly high level.
13:21Yeah. Curiosity.
13:23Yeah. And we all go through life with all these questions in our minds and they won't all be
13:29answered. But when some of them are, it's very satisfying. It's really nice. It is. And having
13:35that curiosity and I get so much joy out of transportation and movement and trying to get
13:42a grip on all of that, that you just want to understand. That's why I write down every
13:48fuel mileage that I get in any vehicle that I'm running. I always track that and I see the
13:54differences when something changes. Cause I've got carbureted cars and old motorcycles. And when
13:59something changes, you can, you can see it in the fuel consumption. Yeah. I'm obsessed. My every
14:04Christmas, uh, I'm always impressed by my father-in-law's, uh, recent model Buick with
14:10some V six in it. It's a pretty big car, but it gets like 27 or 29 miles per gallon. When I take
14:17it on the road, like I drive Peter Egan's in Wisconsin for Christmas to visit and I'm always
14:23impressed. And it's hilarious. Cause my wife is like, I, this year I just finally said, well,
14:29it wouldn't be Christmas if I didn't tell you, I got 29 miles per gallon, 30 miles per gallon,
14:34driving to Madison. So yeah, it's, it's yeah. Just pull the dipstick. Look at that stuff. It's,
14:40it's, it's good work. Yep. So, uh, there's, there's the break-in that is appropriate
14:49to the old time way of building engines. For example, if you're a Triumph restorer
14:55and you, you go ahead and you put that 60 degree crosshatch hone into the cylinder,
14:59which you're turning it into a, an inside out mill bastard file. And it's going to shave
15:06the piston rings into intimate contact. And if you had old time oil that would break in,
15:16in the old way. But if you put modern, uh, Z DDP loaded oil, oil with anti-wear additive
15:28into such an engine and try to break it in, it may fail. It may not break in the piston
15:33ring may just have little highs, shiny places on it here and there, as you described when the
15:38fellow wasn't running so well. And for that reason, uh, at least, uh, one of the high-performance
15:50motorcycle oil manufacturers supplied a break-in oil, which had less of that active ingredient.
16:00Uh, the way anti-wear works, we've talked about this here before, but the way it works is it's an
16:07additive which bonds to the metal surfaces. If they get, if they form a hotspot by local friction,
16:19then a, uh, fairly soft layer of solid lubricant is deposited on those surfaces.
16:28And it can be, it is self repairing from the additive that's still in the oil. And that's why
16:36your oil eventually wears out. It uses up all the additive and there isn't any more.
16:44So you need to put in oil, change the oil to have a fresh load of, of anti-wear. So, uh,
16:54anti-wear is a, is semi-miraculous, but it's also fiendishly frustrating for those people
17:01who are trying to break in engines the old way on new oil. Yeah. It's a, it's been a real issue.
17:06I have friends who work in the vintage bike industry, rebuilding, you know, Triumph engines
17:11and so forth. And I have one fella who, when he gets an engine, you know, he's had a customer
17:18tell him that it won't break in. And he's like, what oil did you use? And he put in some real
17:21disco synthetic, uh, right out of the gate. And then, you know, wasn't, wasn't putting a lot of
17:27combustion pressure in. And that's what, you know, that's what you're looking for to get the rings to
17:32blow out what's happening. Like you want the load, you want the throttle, increase the pressure in
17:38the chamber, which is what inflates the rings against the bore and helps them, uh, seal makes
17:44them seal. And that's what, that's what that 70% throttle that load blow the rings out,
17:52let them retract a little bit off throttle, moderate throttle, wash away the impurities.
17:57In any case, this guy's taking a Triumph that will not seat its rings. That's had synthetic oil in it.
18:04And he's starting the engine and he's putting essentially Borax, Boraxo into the intake
18:13to get that to happen without pulling the thing down and trying to knock the surface off. And,
18:19and it works, it's maybe not your ideal way, but you know, when he's doing a, an engine,
18:24what you were talking about, Udo Giedl doing essentially a dry, a very dry assembly with
18:28maybe a drop of oil on the skirt. On either skirt, dry cylinder bore, dry piston. Yeah.
18:35So clean as can be right. When you're putting that stuff together, you wash the cylinder bore
18:39because it's been through its machining and honing process and you wash and wash on an iron
18:44bore. You wash and wash until your rag comes out white, white as can be. And you clean, clean,
18:50clean, clean, clean. And then you assembled your engine and he puts his Triumphs together,
18:55essentially dry because he wants the rings to rapidly seat and do the deed. And then you just
19:02run the oil and you change it. And then you're, then you can have it last forever. Yeah. After
19:07that, then there are race engine builders that say so many pulls on the dyno. So basically that
19:15is high pressure for a period of seconds followed by resting. Yeah. And except that it's under
19:24controlled conditions of where you're, you're not fighting your way through the usual population of
19:32unpleasant traffic competitors. Right. And what you're doing on a race motor, I mean,
19:38you know, production engines have evolved so much. The, the finished processes and all the machining
19:44has been greatly improved. Yeah. Yeah. For lack of a, sorry, sorry about the pun here, but honed into
19:51a fine. Anyway, sorry. I apologize. But, um, it's improved so much. Yeah. It's, it's improved so
20:01much that, you know, we used to talk about blueprinting an engine and that is really
20:06truly dimensioning everything and checking, checking all your journals and a good crank guy,
20:11you should be able to set your mics. When the crank comes back, you should be able to say,
20:15oh, I can check my mics on these and they'll, they should all be the same. They should all
20:19be perfectly round. The finish should be exquisite. And that is the, that is the quote blueprinting
20:24of the engine is making sure that everything is as perfect as you can make it. And that's
20:28what's happening in a race shop. And so the idea of breaking in an engine on a dyno is we already
20:35know that the journals are nearly perfect. And we already know that we've lapped the rings to the
20:39bore. And now we're just putting that final wash on it, getting that combustion pressure. And then
20:47we change our oil. And you were talking off camera about NASCAR folks who do a break in
20:53like this. And then they changed the main bearings and the rod bearings because,
20:58well, they've got garbage in them, but now that it's broken in, we'll put these pristine ones back
21:03and a boy we could, we could go that far, but it's a lot of work on your, you know,
21:07Honda that you want to commute on. Yeah. Well, I should make it clear that there,
21:12we're talking about multiple levels of concern here. Most people are going to buy a motorcycle
21:19and operate it and they're going to turn it over at some point, or it will enter their
21:24permanent collection. And they don't, maybe like Mike Hailwood, they'll say,
21:31I don't really know or care what's going on inside my engine, but I don't want to do harm.
21:39And so they're not very engaged and rightly so. We hope that people will buy production equipment
21:46and enjoy the pleasures of it without having to fiddle with all this. Then if you're building
21:54rebuilding an old, an older engine as a non-professional, that's another level.
22:01And then the racing people, they're up in the stratosphere somewhere with
22:07what they've found to be useful. And, and all the tools that would go with it, all the bore gauges,
22:13all the mics, you know, when you're measuring your piston, you have to, you have to have a,
22:19a big mic that's a horseshoe shape that would go between three and three and a half inches.
22:23And then you need the ones that fit other pistons. And so you end up like Kel Carruthers
22:28when I visited Kel Carruthers at his house last year, you know, he had his entire toolbox of
22:34measuring devices, just like hundreds of Mitutoyo and, you know, Starrett gauges, all kinds of
22:42different sweep gauges, which is kind of one with a little arm that you stick on something round,
22:47and it goes like this, and the dial says, and you have straight dial indicators, four gauges.
22:51And that's where the, the professionals are, are really looking at every possible dimension
22:56and perfect sealing and the minimal amount of friction and all that hoo-ha. And again,
23:03factory engines have, have come so far from, from what a Triumph was. I mean, imagine,
23:10imagine a 1967 Triumph or a BSA, you know, I've talked to, I talked to a BSA dealer
23:16about how every BSA in the late sixties essentially had to be remanufactured out of
23:23the crate because everything was just all over the place for their customer to be happy. You
23:28talk about the final, the final bit of production being break-in, the final assembly was actually
23:35happening at a US dealership. Sure. We had that, we had that. So to a certain extent,
23:42we had Triumph 250s and they came with a whole bunch of parts and said, this is all warranty.
23:50Engine out of the frame. Oh, and the engines didn't fit the frame. You felt knocking the
23:57engine bolts out. You felt like you were driving spikes on the transcontinental railway.
24:02Wasn't that a lesson? The first time I took an engine out of a Triumph, I went to you know,
24:07I went to put it back together and I, I got the engine in place and I, I put an engine bolt in,
24:12I'm like, oh, that was good. And I, you know, snugged it up a little bit and I went to put
24:16the next one in and I'm like, well, that doesn't, that doesn't fit. You don't, you don't tighten
24:20that. Yeah. You don't tighten those bolts. You get, you leave them real loose and then you start,
24:25you start getting your long tapered rod and you start levering. Line up punch. Yeah. Yeah. That's
24:33so it's, uh, the purpose of it was to make up for manufacturing error.
24:39Well, when you see the old videos in the Triumph factory of the guy forging, uh,
24:43basically SIF bronze, welding the lugs on a frame in a, in a pit fire, it looks like a coal fire,
24:50like an, like you'd be barbecuing on and he's sticking portions of the frame into that to heat
24:55it and then sticking rod in it and flipping it around and hitting it with a hammer. I wonder
25:01how did that ever work? Look at us now.
25:07And humans used to do the welding. Yeah. What are that? What are they?
25:12Employees expensive. Can't have that. So, uh, but the basic thing about breaking is
25:21that it is a process of reducing the asperity height, the, the irregularity of surfaces
25:28so that it is substantially less than the thickness, the minimum thickness of the oil film
25:34during engine operation. And all surfaces looked at in molecular scale are rough.
25:43They are not, you can't polish more and more and more and finally have a perfectly smooth
25:49surfaces because it's like paving a room with basketballs and then trying to walk.
25:54Those are the atoms. So there is no perfect surface. There are only better surfaces and
26:02break-in is seeking to create that better surface and late model stuff. Much of the break-in has
26:09been already accomplished through a more sophisticated manufacturing techniques,
26:15such as pre-lapping of piston rings and, uh, super finished journals on crankshafts.
26:22But that's much of the story. Yeah. Well, we've done a test, uh, here at one of our titles at
26:30motorcyclist. And, um, we had a fellow on staff who was, uh, building Honda engines, uh, CRF 300,
26:39CB 300, the single that they use in the entry-level bike and he raced them. And so he decided to, uh,
26:47do two engine rebuilds, put two engines together, uh, all the same tolerances,
26:52all the same measurements, did all of that work and, uh, plopped the first engine into a, uh,
27:00a CB 300 and did a 1000 mile run oil change at 600. And, uh, you know, never rev the engine hard,
27:08never use the throttle hard, et cetera, et cetera. And then pull that engine out and put another
27:14pull that engine out and put another engine in and hammered it. And in fact,
27:22another thousand miles, all the same treatment took the engines apart and redimensioned
27:28everything and inspected everything. And they were virtually identical.
27:34They were identical. Nothing. There was essentially, there was no difference.
27:39So we're, we are at a point where with new motorcycles and new manufacturing and new
27:45machining that it's close to finished by the time you get it, like your rental car was seven miles.
27:55It's basically close to finish to treat it. Right. You know, we don't need 15,000 RPM shifts with six
28:03miles on the clock. Like, let's not, you know, let's not be abusive, but yeah, you know, treat
28:09it right. And you're, you're going to be safe following the break-in recommendation in the
28:16manual. And I would, my addendum to that would be, I want to seek some combustion pressure
28:23in the cylinders. That Ducati, that Ducati back there, I bought with 853 miles last year,
28:30853 original miles. I've, I've been breaking it in. I, I wrote it to 1500 and it's different.
28:37And it runs differently. It runs better now it's freer, it's happier. And I, you know, I changed
28:43the oil when I got it. I did all the things to make it run again. Cause obviously it had not
28:47been running much over the last 28 years. Got it all, got all tuned up and belts and carbs and
28:57ignition and all the things. And I put some compression, combustion pressure behind it,
29:03you know, and I kept the revs under 6,500, 7,000 and away we went. And it seems like a
29:11pretty happy motorcycle with low oil consumption. It was like riding a new bike from 1995.
29:17And the oils, the oil was a beautiful color. I took the oil out at about,
29:21uh, oh, 700 miles of, of riding. And, uh, it was a very nice color. It wasn't perfect,
29:28but it was a very nice color. I remember that when Aprilia first went super bike racing with
29:33their V twin 60 degree V twin, that when they were warming that thing up, uh, the moment that
29:42the mechanic dropped the throttle, the engine just stopped. It was like there was some horrible
29:50resistance inside of it. I don't like motion. I will oppose it at every occasion. And then
29:59the following year, it was completely different. They're warming the thing up casually.
30:05And when the mechanic dropped the throttle, it went good. Like you expect an engine to do.
30:11It coasted down and stopped. It didn't act like it was full of jam.
30:19So I always wondered about that. I assumed that it was something to do with the valve train.
30:24That's yeah. I mean, that's an interesting point. And then I, I wonder about, uh, crank mass and
30:31other, other things like that, that, you know, I think sometimes we, we go too far with saying,
30:38we want all the acceleration to happen at the, at the wheel or now we're opening a new volume
30:46here. Yeah. That's a different, different show. Um, but we'll get to it. Yeah. I think
30:55one thing I want to talk about, uh, related here is, uh, something I learned about with, um,
31:02my valve set in the rebuild and going to a, um, a Nickasil nickel silicon carbide
31:09plated bore with the plateau finish. And, uh, you brought that up in our discussion about this show.
31:17And why don't you give us a little insight to what that actually means and how that would work.
31:23It used to be that if you were preparing a,
31:27preparing a, any kind of engine with an iron bore that you, uh, put the hone in and
31:36adjusted it to produce a certain wall pressure and you squirted in some oil and you stood there
31:43working your hands up and down, holding the drill motor and striving to produce the
31:51time honored 60 degree crosshatch hone pattern. And of course the individual little abrasive
31:59grains that are bonded into the hone stones are like a lot of little shark teeth and their effect
32:06on the cylinder wall is to gouge it. And the edges of it's not going to be a nice little V
32:14the edges of the V there's going to be material pushed up. And that's what used to turn your oil
32:21black when you did a classic break-in is lots of wear particles going into the oil.
32:28So the plateau finish you switch from the medium well toward the coarser end
32:37for the 60 degree crosshatch, you switch to a fine hone stone set of stones and you hone
32:46for a certain number of strokes with this aim in mind that the cylinder bore will be as though
32:57it were a smooth surface with irregular little drainage ditches running here and there.
33:06And what the piston ring engineer told me was that when a hot spot develops,
33:12when the near scoring condition scoring is welding of one surface to the other,
33:20which of course is then torn and the wear particles then gouge the rest of everything
33:26that is you've made as perfect as you could. I should have brought some pistons in because I
33:32have way too many of those. But the coarse grooves in this otherwise very smooth surface
33:43provides a place for those wear particles to be ditched. Those are the ditches where
33:53where any problem is pushed into that area and no longer there's a good chance that the piston
34:01in the ring and the cylinder wall will run sweetly rather than score and have those vertical
34:10lines that you've seen and you've thought to yourself, I have to address this problem sometimes.
34:16Well we want only the contact that we want. We don't want that other stuff. We want that to go
34:21down the sewer, into the crankcase and through the oil filter and trapped never to be seen again.
34:28When I was doing two strokes, I would always see this the Fu Manchu
34:34lines from the, if my mouth is the exhaust port, the Fu Manchu lines went down from the sides of
34:40the port. And when I started using a rubber abrasive wheel to ever so slightly radius
34:46the edges of the exhaust port, those lines were no longer produced. So I was very pleased with that.
34:53We all want to understand more than we do at the moment and we all hope for better.
35:03So this is why constantly thinking about these things is productive because you will
35:11have some chance of coming up with things to try. They won't all work but when one of them does,
35:18you never forget it. Oh, it's great. Yeah, it is great. Yes.
35:24Okay, so engine break-in these days with a new bike, you don't have to worry about it too much.
35:29Follow recommendations. We're going to say inflate your rings, give them something to think about.
35:35Don't over rev it but don't worry about it too much. Treat it nice but not too nice because
35:40you want it to seat. You want it to run. You want it to run. Push those piston rings
35:46deeper into the oil film so that the asperities are polished away. Yeah.
35:53That's what break-in is. Yeah. And in fact, the super finish process that Chrysler developed for
36:00radial engine crankpins was sort of similar in that they made these saddle-shaped abrasive stones
36:09that would clasp the crankpin journal. And they started out the process with cool oil
36:20that would support those abrasive, those honed stones on a complete oil film. There was no
36:27asperity contact. And then as the process continued, the temperature of the oil would
36:34be allowed to rise, which would mean that the stones would move slightly closer to the surface
36:42of the journal. And in this way, by controlling the temperature and therefore the viscosity of
36:48the oil, they could control the approach of these stones to the journal. And they could just begin
36:57to take off the tips of the asperities and then more substantial amounts until they got the
37:05finish they wanted. It would be truly cylindrical. It wouldn't be like
37:10taking polishing powder and rubbing it on the crankpin. That doesn't get you anywhere because
37:16locally you'll see that the surface is all in ripples. Some parts of the crankpin are harder
37:21than others. So if you try to use a polishing idea, like you're shining your shoes, the softer
37:28areas will be cut more deeply than the harder areas. Metal. Better not to think about it too
37:36much. There's a lot going on in metals. Yeah, absolutely.
37:44Well, thanks for watching everyone or listening. If you're catching us on Spotify or Apple Podcasts,
37:50we appreciate you listening. Sometimes we have show and tell when we're on YouTube. You can
37:56see us holding up broken parts as we did in the show last week. We appreciate your comments.
38:04Get down there and in a future episode we will talk about some of the questions in the comments
38:11or adopt some topics from the comments. There's been great stuff going on on all the videos on
38:16YouTube and we appreciate you listening. Like, comment, subscribe as they say. It'd be
38:23much appreciated if you subscribe to us and got notified if you like the show. So
38:30thanks for listening. Thank you, Kevin.