Presents:

Circular Logic
De-Mystifying Main & Rod Bearings

In this article I'm going to show you something in an engine which is so fragile, that it can be easily destroyed by the friction from a wimpy piece of paper towel.

Most likely, that will now seem unbelievable, 
which is in keeping with almost everything else on 
Power News... 

Paper Towel !!

This Website is The Most Informative Tech Site On The Web

Hi MotoMan.

It's not fair to tease us with a list of upcoming articles that look so interesting. I want to read them now. This is the most interesting and informative tech site on the web. Keep up the good work.

~Damian
(Australia)

Hi Damian !!

This issue is about one of the most widely misunderstood topics in engineering, so it was harder to write than some of the past ones -- plus it required many diagrams, animations and photos to visually illustrate the concepts.

Thanks for your support, I think you'll find that it was worth the wait !!

Sincerely,
~MotoMan

The Ratio of 719 to 1

Hi MotoMan,

Interesting (Break-In Secrets) article.

I bought a new W650 parallel twin Kawasaki three years ago. I had read of an Australian race car tuner who developed a running -in strategy similar to yours. His was to start the brand new motor, warm it enough to be safe, get it into third (or some gear where the load was high but the speed not silly) and then nail it to the red line and allow it to come down to idle before repeating ten more times, making a total of eleven. Taking my heart into my mouth, I did this with my brand new twin.

About 1000 miles later, I ran it on a dyno, and it posted 51 bhp...not too bad for a street, long stroke 670cc parallel twin. I belong to an enthusiasts group and typical horse power levels for motors run in by the manufacturers methods run from 41 to 44 bhp ...

Says it all really... I have one of the most powerful machines out of all the 720 members!

I'm glad someone else is prepared to put it on the line!

~ Jon 
    UK

Hi Jon !!

Yes, that's a huge difference !! The key is to warm the new engine up, then run it hard. Many people have thought that since the vehicles are ran this way at the factory, they are already broken-in. As you've found out that's not true, since each of the other 719 bikes were also run hard at the factory. That only starts the process, and as you now know, it's up to the consumer to achieve the ideal ring seal.

Before you tested the hard break-in concept, it would have been reasonable to say that 41 - 44 Hp is the standard of "full power" for the Kawasaki W650. From this limited perspective, everyone would be happy. 

But, since your engine is delivering its true potential, your bike has become the actual standard of what "full power" really is. The new (big picture) perspective now becomes: 719 engines haven't developed full power. That's a big paradigm shift.

That paradigm shift is the reason so many people are now discovering Power News. Congratulations, and thanks very much for your support !!

Sincerely,
~MotoMan

P.S. To the Australian race car tuner: My "hat's off" to you !!

She's Learning Fast ... 

Hi Motoman,

I am a 21 year old female who has never had any interest in motorcycles. In fact, I even hate driving cars and do so about once a year (or less). However, I decided to buy a motorcycle and to hell with my narrow-mindedness. I’ve been reading motorcycle-related material on the web all day, but I am totally lost. I know nothing, and I mean NOTHING about motorcycles. They all look the same, I have no idea how they work (or any engine for that matter), and it is a wonder how anyone actually manages to drive them. All the abbreviations and codes are a complete mystery to me. Also, some sites contradict each other – adding to my confusion.

I read all of your newsletters because—well--they're fun to read, and after a while I found that I understand about 35% of the technical stuff. This is very encouraging. I understand, of course, that yours is the wrong site for a beginner to learn the basics, but I was hoping you could help me. 

I'm not stupid, just not-so-mechanically-inclined, and I could use all the help I can get.

Self consciously yours,
~Ilana

Hi Ilana !!

Thanks for your comments, it's very encouraging for me to read them !! 

Even if you never plan on working on cars or bikes, understanding how they really work will save you a lot of money, whether you're buying a new or used vehicle. You'll also gain valuable insight into how to dramatically increase your engine's life ... without even getting out any wrenches !! That's why I think that Power News 
is the best place to learn the basics about engines. 

As a bonus, it will help you avoid being ripped off at the mechanic's -- something that happens to a lot of men too, although we don't like to admit it. ;)

The only thing I would add is that if you get a new bike and you want to break it in right, I'd suggest having an experienced rider do it ... running a motorcycle hard is not my recommendation for a new rider !!

Sincerely,
~MotoMan

The Challenge:
After reading this issue, I will guarantee that Ilana will have a better understanding of how engines wear than most experts, including many Factory Race Team tuners !!

The #1 (unwritten) rule of journalism: 
Never Upset The Advertisers

The #1 rule of science: 
Always Consider Alternate Explanations
Even if it means having to rethink what we already knew.

Thinking outside of the box is usually associated with creativity, and doing things in a new and improved way. (Right side of the brain.) 

But, the left (Logic) side of the brain can be seriously limited by in the box thinking. Some can't see the possibility that there might be another, even more logical explanation for things, and this limitation can be easily exploited. 

Try this perceptual test:

It Was Our Perception That Was Fooled, Not Our Eyes !!

These things are called optical illusions, but they should really be called Perceptual Illusions, because the problem isn't with our eyes. The symbols created by the converging lines tricks our brain into taking a mental short-cut, and we interpret the visual information incorrectly. 

Observation, in the form of actually measuring the difference confirms the illusion. (Please don't take my word for it, measure the lines in the original picture for yourself ... this is important !!) 

Of course, we aren't stupid for being tricked by perceptual illusions, it's a normal thing !!  But, notice that once you became aware of the perceptual problem, it became easier to see that the top line is at least not as long in the original picture, as it seemed the first time you saw it.
When you become aware of a particular perceptual problem, you're less likely to be tricked by it the next time. 

Ironically, We Often Learn To Take Mental Short-Cuts In School !!

In school, most of the information we read is in textbooks, which are automatically assumed to be 100% correct. This effectively trains us from an early age to read for one just thing ... the memorization of facts. Once out of school, as long as information seems prestigious, it never occurs to most people that it should be questioned or analyzed. 

Thinking is much more than just memorizing and repeating facts, but unfortunately, most formal educational systems measure and reward their students only according to their ability to memorize and repeat information. That's good, but it's not actually thinking.

This substitute for thinking usually becomes a lifelong habit -- a habit which invites perceptual problems !! Taking mental short-cuts severely limits our ability for rational thought.

What Does This All Have To Do With Engines ??

In this issue we're going to examine 2 articles which have been cited as intelligent and sane break-in information, especially as they pertain to main and rod bearings. One was written by the most well known tech writer in the US motorcycle magazine business, and both have quoted famous factory team race tuners as their proof.
Expert status and prestige make it extremely difficult to focus on the logic. 

The problem is, these articles (and others like them in the auto world) have been uncritically read and successfully memorized. The facts contained in them have been in turn passed on to millions of people. As far as I know, these facts have never been questioned in a widely read publication.

Warning:
These articles have been endorsed by many with a high level of education in science and mechanical engineering, and many highly trained professional mechanics !!
Most experts agree that these articles contain solid, scientifically sound information.

The Next Door Neighbor Critical Reading Technique

A quick read of these articles won't reveal any problems, but a careful read will reveal lots. The amazing thing is, you don't even have to know that much about engines to notice some of the problems, if you use my critical reading technique.

This technique is simple in concept, but it takes practice before it becomes easy to do consistently. The trick is to remove two of the most powerful perception distorting symbols -- expert status and prestige ! This makes it easier to consistently perceive reality using logic outside of school ... where it counts in the real world. 

So, when you read these 2 articles, pretend that they weren't written by famous, well respected tech writers and published in 2 well established, widely read magazines. 

Instead, pretend they were written by ...   
                       
                          ... your next door neighbor on a piece of scrap paper !  

No Disrespect !!

This technique isn't meant to disrespect the magazines, the authors or the quoted tuners. The idea of critical reading isn't to criticize people, it's to critically examine the ideas. (I suggest using the next door neighbor reading technique with my writing, as well as everything else 
you read !!) 

My personal opinion is that Kevin Cameron writes the most interesting tech articles, and I'm a big fan of his articles dealing with the nostalgia and the old days of racing. But, that doesn't automatically mean that all of his technical information is correct.

(Note: when you click on the links, these articles will open up in a new window.)

Here's the first article. It was featured in the 1995 Sportbike Annual and it's entitled 
"It's New, It's Pristine, How Long Do You Have To Baby It ?" :
http://www.dezmo.com/breakin.html

The second article is an excerpt which was featured in the Feb. 1991 issue of Motorcyclist magazine and it's entitled "Give It A Break-In". 

Important -- the longer excerpt, which is the one we'll be studying here, is the second post down on this page:
http://www.kawiforums.com/forum/topic.asp?TOPIC_ID=1380

2 Important Notes: 

1) I hope these articles stay on the internet for the future readers of this page, but because of possible copyright issues, the links to these articles may become unavailable. (Under fair use copyright laws, it is only legal to quote parts of an article for evaluation purposes, so I'm not going to be posting these entire articles on this site.)  

This Power News article will concern the bearings only. In future issues, we will be referring back to both of these break-in articles on the topics of ring sealing and other aspects of their information. For this reason, I suggest either printing them out, or saving the text of these 2 articles as a document on your computer for future reference, in case the links disappear.

2) Some people haven't noticed any difference between my break-in method and the method described in these articles. 

Although these articles recommend a slightly "harder" break-in than the owner's manuals do, I'm saying that an immediate hard break-in is required for the exceptional ring sealing benefit, and as long as the engine is warmed up first, this won't cause any damage; whereas they are recommending first running gently for a while before running moderately hard to avoid severe damage. The problem is that this completely misses the exceptional ring sealing benefit, which is the whole point of my break-in procedure.
The time frame and the damage warnings make these 2 articles the total opposite of Break-In Secrets.
This is why I will be referring to them as "easy break-in" articles, so there's no confusion as to the difference.

Many people have tried to "mix" the 2 break-in ideas by first doing an easy initial break-in, ("just to be safe") and then after a while switching to my method. They've been disappointed when they found that there wasn't a significant power gain, and many have decided that they might as well have followed the owner's manual. If you understand what just happened, you'll realize that what they really did, was exactly what is described in the easy break-in articles !!
The method described in those articles will produce nearly the same results as an owner's manual break-in. 

Once the engine has some easy initial mileage on it, it may help a little bit to run it hard. It's definitely better late than never, but it's not going to make the remarkable difference that so many people are now discovering.

The reasons for this as well as my explanation for how rings seal will be illustrated in future articles with diagrams and animations. 

Today's article will address the widespread misunderstanding about how bearings work, as well as the "severe damage" question as it pertains to bearings during new engine break-in.

Ball bearings are among the most closely dimensioned parts in the world of manufacturing.

Ball roundness and size as well as surface finish 
are held to a micro inch specification. 

1 micro inch = 1/1,000,000th ... 
 ... one-millionth of an inch !!

The races that the balls run in are finished to this 
level as well.

I'll admit, I can't think of any reason that 
they should require break-in.

A typical ball bearing assembly 
used on the transmission shaft.

The wheel bearings used in motorcycles are of the same basic design.

Rod Bearings:



The tab on the bearing insert fits into the notch in the rod. This locates the bearing in the 
center of its housing.



When the rod cap installed, the complete bearing is formed. In an actual engine assembly, these 2 halves are connected onto the crankshaft journal.

(The word "journal" means the crankshaft's running surface for the bearings.)

The main bearings are located in the crankcase with the same tab / notch system.

Main Bearings:

The picture below may look intimidating if you're not familiar with engines.

It makes it a lot easier to think of the 2 crankcase halves as in the same way that the 2 halves of the rod assembly go together. 



As you look at this picture, you'll see that there are really only 4 different parts to the main bearing arrangement: the crank, the bearings, 
and the 2 cases which form the 
main bearings' housing.

(There are many other engine parts missing here -- this is to make it easier to see only the main bearings and the crankshaft, and 
how they fit together.)

Just like the rod bearings, the main bearing halves go together to form a complete bearing shell which surrounds the crankshaft journals.
.
.
.

Here's how the rod connects to the crankshaft journal. The rod on the left is unassembled with the cap and nuts. The rod on the right 
is bolted in place.

Notice that those pistons had an excellent ring seal.

Note: this picture isn't visually accurate, it's more to illustrate the conceptual idea. As you can see, before the bearings are installed, the bearing shells are wider than they are high. This is because the bearings also have a spring effect, which makes them press into the 
bearing housing.



The point is that once the bearings are installed into their housing, the dimension "A" of the bearings is slightly larger than the dimension "B" of the big end of the connecting rod. (This is also true of the main bearings and the housing formed by the crankcase.)

This picture of the rod's lower cap illustrates the crush concept. If you look closely, you can see that the end of the bearing insert is sticking up above the rod cap slightly.

I purposely pushed it up a little more than it is in actual reality, to make it easier to see in a photo.

The bearing "sticks up" like this in both the upper and lower part of the rod, and when the parts are bolted together, the bearing shells are "pressed" in what's known as an interference fit.

In the same way, the main bearings use crush to achieve a press fit within the crankcase halves.
.

The running surface of the rod bearing is over the entire width of its surface, while the main bearing's running surface is only on the 2 outer sections indicated 
by the arrows.

(The oil channel in the middle is below the running surface.)

In this animation, the oil clearances have been greatly increased to give a clear view of the oil film's dynamically changing dimensions between the bearing and the crank journal.

(The average normal oil clearances for main and rod bearings are around .002 inch / .05mm.) 

The bearing itself doesn't "do" anything. The crank journal surface floats above the bearing surface, on the oil film.

(This assumes proper oil pressure, bearing-to-crankshaft oil clearance and correct bearing installation.)

The crank journal is dark gray, oil is dark yellow, 
and bearing is light gray.



As the engine rotates, the crank journal goes "off-center" within the surrounding oil supply. Although it can move within the dimensions of the volume of oil, the crank journal surface itself never contacts the bearing.

Both main and rod bearings work this way.

Bearings are fed pressurized oil. This pressure is critical, because although the crank can push the oil aside, it's the pressure which keeps the crank from breaking through the oil film 
to contact the bearing.
.

At first appearance, this system seems like it shouldn't work.

It works only for one reason:
Oil, like all liquids, is non-compressible !*
.

Check Out These Websites
To Learn More:

For Komatsu Sales In Norway
http://www.hesselberg.no

Arne Sandum
Sales Manager

For Komatsu Sales Worldwide
http://www.komatsu.com

(The 2 links above open in a new window.)

Team Komatsu-Yamaha Norway
By letting the race fans try out the equipment, 
2 Time Norwegian National Roadracing Champion Dag-Steinar Sundby and his team have done an outstanding job of promoting their sponsor !!


MotoMan "Digs" Komatsu !!!
The thing that really impresses me about Komatsu is their commitment to long term reliability.

Check Out Their Automatic Grease Injection

If you're in the market for heavy equipment, 
please consider the purchase of a Komatsu !!
.

Embed-ability
The babbit layer is about as soft as lead, and it can be easily scratched by harder metal.
This is by far the softest metal in an engine.

The purpose of this soft metal layer is so that any metal fragments in the oil supply will embed into the soft bearing, leaving the expensive crank unharmed.

The copper layer is harder, making it an ideal 2nd layer material. It's hard enough to support the babbit layer, while it's soft enough to allow it to "give" when a bit of metal is embedded in the babbit layer.

The steel layer gives the bearing its strength and "spring" so it can be installed with a slight interference or press fit into its housing.

Because of the embed-ability requirement, the bearings are fragile. If there is crank journal to bearing contact while the engine is running, the soft 
babbit layer is easily damaged.

3 Metal Layers



The copper layer looks thicker than it really is ... because I cut the bearing at an angle to make it easier to see the layers in the photo.

Also note the magenta-red paint marking on the side edge. This is to indicate the bearing's thickness. Bearings typically come in 4 or 5 sizes to accommodate slight differences in crankshaft journal diameter. 

Note: The size differences for motorcycle engines are extremely small, approximately .00016 inch / .004 mm for each size increment. Some car bearings have a much larger range of sizes. This difference has caused much confusion in the motorcycle world, and this subject will be covered in the next issue.
.

This bearing surface has very effectively "absorbed" some metal bits. As you can see, there wasn't any scoring around the bearing. If the metal surface of the bearing were hard, any debris in the system 
would ultimately score the expensive crank. 

The only drawback to this design concept is that as more and more bits are embedded, the bearing surface immediately surrounding the embedded bit raises, and tightens up. 

Eventually, if there is enough loose metal or grit embedded into the bearing surface, the overall clearance can get tight enough to cause metal to metal contact with the crank journal, 
resulting in bearing failure.
.

Embedded Metal Bits In 
A Main Bearing.

Main Bearings

The main bearings' oil comes from the crankcase, and enters into the bearing shells, through the 3 pressurized oil delivery holes in each bearing. (In the diagram, the 3 holes at the top are marked, but there are also 3 more holes in the lower bearing shell.)

Like the earlier animation, notice that as the crank rotates, the journal is "off center" within the oil clearance. The forces on the crankshaft cause the journal to displace oil within the "container" formed between the journal and the bearing, but it can't physically compress the pressurized oil.

(Again, the oil clearance dimensions have been increased for illustration purposes.)

After the oil flows between the bearings and the journal, the next route of its path is into the hole represented in the center of the crank journal. This hole leads the oil to its next destination ...

Note: As mentioned earlier, in some engines just one main bearing in the pair has oil delivery holes.
.

.
The oil flows from the main journals marked "A", to the rod journals marked "B", through the passages drilled within the crank, (denoted with a red line). 

The direction of oil flow is indicated by the green arrows. 

This is a clever system, because it isn't practical to have the rod bearings' oil supplied from a static source the way the mains are, since the rods are moving over a large area.

Another interesting thing about this is how the passages are created. The crank can't originally be made with internal connecting holes, so they have to be drilled from the outside. The outside of these holes then have to be plugged, to form a closed system. The hole is plugged with a ball, and then the metal around it is peened over to keep the ball in place. The balls are marked "C". 

(As you can see in the photo, the inspectors at the factory double check and then paint the ball areas to signify that they've been securely peened over. A loose ball 
would be a disaster !!)
.

Oil Passages Within 
The Crankshaft:



With the connecting rods removed, it's easier to see how the oil flows.

The oil enters the crank through the main journal holes "A", then exits the crank from the rod journal holes "B".

Because of the direction of oil flow, if there is any debris inside the crankshaft oil passages, the main bearings aren't affected, but the rod bearings 
will be damaged.

If you've never dug into an engine this "deep", you may be surprised to find that the connecting rod can be 
moved from side to side quite a lot !!

At first it seems so wrong !!
.

It does seem "wrong" but, this rod side clearance is required, because it's the only "escape route" for the oil 
on most engines. 

It's also the way the piston and rings are lubricated.

The pressurized oil leaves the rod bearing - crank journal interface through this clearance, and the oil sprays up to lubricate the piston, rings and cylinders. The oil then drains down to return to the sump at the bottom of the engine, 
to start the cycle over again.


Note: as mentioned above some engines use an oil hole, but these designs also have some rod side clearance. 

Here, I've pushed the rod to one side so it's easy to see the clearance between the rod and crank cheek.

On most motorcycles, this clearance is .004-.006 inch / .1mm-.15mm.

Larger motorcycles and car engines often have a bit more rod side clearance, but the principle 
is the same.
.

1/2 The Story
What if a newspaper reported that a man jumped from the 100th floor of an apartment building, and miraculously escaped the ordeal with only a sprained ankle ??

But, what if the newspaper reporter didn't know that the man only landed on the balcony, 3 feet below the window he jumped out of ??
.

This is like the famous scene in the Wizard of Oz when Dorothy got to see how it all works ... except this is real:

Those Disturbing 
Pixels of
Debunkification

The bikes aren't just "likely" to be run at the factory, in fact ...

The factory technicians give all new bikes a 
Full Throttle Max RPM Blast  
through the gears !!

The magazine tech writers and the factory race team bosses and mechanics quoted in these articles don't know about this aspect of the manufacturing process !!!

MotoMan

"Gee Whiz ... you can't really violate the logic of the easy break-in articles any more outrageously than that."

.
.
.
.
.

.

.

.
At the factories, there are magical Dweeb-a-zoids
who send a re-integrating micro-particle beam, which fully protects the engines from damage, while they get pinned to the max and blasted into the stratospheric part of their rev band !!

Alas, the Magical Dweeb-a-zoids vanish the moment 
the vehicle leaves the factory.
.

Those Rarely Seen
Factory Dweeb-a-zoids

.
But ...

Once you take ownership of the vehicle, the "still scientifically valid reasons" contained in the easy break-in articles will instantaneously go back into retro-effect !!

You see .... that's because for the next 600 - 1,000 miles, 
your new engine will be haunted by ... 

The Evil Hobgoblins !!
.

The Evil Hobgoblins

To be fully convinced, people have to really believe in an idea, not just mentally, but in their heart. 
The statement below is effective because it evokes the most powerful emotion of non-thinking, which is of course: 
fear. 

A Frozen Moment of Crystalline Clarity

Quote from the How Long Do You Have To Baby It article:

" If the break-in begins at high RPM and heavy throttle, the process may generate more heat and metal debris than the system can handle. Then the result is destruction of contact surfaces in some parts of the engine. "

(Hey wait a minute ... that precisely describes what the factories 
have been doing for over 20 years !!)

(Hey wait another minute ... that precisely describes what is 
recommended in the Break-In Secrets  article also !!)
.

.
The main bearings are in a fixed position in the crankcase, the main bearings don't rotate.

Although it's not possible to see the lower main bearing shell in these pictures, I've painted the area they are fixed to green, to make their non-moving status more apparent.

(In a running engine, the upper case would be in place, which forms the other half of the complete bearing surrounding the crankshaft.)
.

           
The main bearings simply support the crankshaft as it spins continuously within the bearings, but the bearings themselves don't move.

.
Backwards ??

Here the rod bearings are green -- notice that they only rotate about 
15 degrees, or 1/24th of a turn, pause and then rotate about 1/24th of a turn 
backwards in the opposite direction !!

The process is repeated for a total of 4 back and forth movements 
per each full revolution of the crankshaft. 

Remember that since the bearings are in a fixed position, they move along with the rod. If it's hard to see that the bearing rotates backwards, try concentrating only on the change 
in the angle of the connecting rod as you watch the green bearings.

The crankshaft's rod journal is colored red. This makes it easier to see that the crankshaft 
and its journal are all one solid part which rotates continuously in one 
direction within the rod bearings.
.

As the piston descends from the top to 1/2 its stroke, the crank is rotating clockwise while the rod bearings are rotating counterclockwise. The speed differential between the bearing and the journal is dramatically 
increased !!

(To see which way the rod bearing rotates, it helps to focus on the line that represents the split between the upper half of the rod and its lower half.)

Increased Surface Speed Differential

As the piston descends from 1/2 its stroke to the bottom, the crank is rotating clockwise while the rod bearings are now also rotating clockwise. The speed differential between the bearing and the journal is now dramatically 
decreased !!

Decreased Surface Speed Differential

As the piston ascends from the bottom to 1/2 its stroke, the crank is rotating clockwise while the rod bearings are also rotating clockwise. The speed differential between the bearing and the journal is the same as the frame above -- decreased !! 

(Note: decreased in relation to the first frame.)

Decreased Surface Speed Differential

As the piston ascends from 1/2 its stroke back to the top, the crank is rotating clockwise while the rod bearings are now rotating counterclockwise. The speed differential between the bearing and the journal is again dramatically increased !!

Increased Surface Speed Differential

.
So, while the main bearing to journal speed is constant at a given RPM, the rod bearing to journal speed is actually much faster during 2 key portions of the engine cycle at the same RPM !!
. 

The last half of the exhaust upstroke, from the picture on the left to the one on the right is the number 1 stress point in the 4 stroke engine cycle !!

In this photo, the image of the rod on the right has been modified in Photoshop to illustrate the effect high RPM stretch has on the big end 
bearing's bore.

When dimension "A" is increased, dimension "B" becomes smaller.

( Note: the dimensions have been greatly increased to make it easier to see this effect.)  

Why is it so important to measure (test) things for yourself ??

The (symbolic) power of prestige has a very powerful effect on preventing new information from being known. (One famous tuner teaches the unquestioning next person who becomes the next famous tuner who teaches the unquestioning next person etc...) 

This might not seem like a fair statement, since these easy break-in articles appeared in the 1990's, and this bearing is from a 2000 model. Believe it or not, the oval bearing solution was developed in the auto racing scene ...           
                                            ... during the 1950's !!
In this case, the conditions of the experiment began to change way back when Elvis was the man on the radio. 50 years later, many scientifically educated engineers, mechanics and race tuners still haven't observed this change. 

The most important concept of science isn't memorizing facts, it's observation of phenomena.

Throughout history, most of the really big innovations and inventions were made by people who rejected the idea that people should be trained to think a certain way.

In the 1950's, thousands of professionally trained automotive engineers thought that engines couldn't be revved any higher. Guess who found the solution ?? A "non-trained engineer" who was able to think freely !! Had everyone just "Stayed In The Box", the 15,000 RPM plain bearing production engines that we now take for granted -- wouldn't be possible !!

By saying this, I don't mean to imply that formal engineering training is unimportant -- it's very important. But, it's equally important to keep an open mind, as that's the key to the development of innovative technology.

Now, 15,000 RPM might sound impressive, but for 2004, Suzuki's GSXR 600 revs to .... 
16,200 RPM. 

That's a production engine, and there's no doubt that racers will push that limit even higher !! Of course, the bearing design isn't the reason that the engine makes power at such high RPMs -- that has to do with the tuning. There are also other factors that make this ultra high RPM possible, (for example, the engine uses lightweight titanium valves.) 

But, the bearing design which was developed in the '50's allows that to happen without engine failure. With "round" bearings, the high revving fun would all end in an instant.

Think about it: Today's 16,200 RPM machines were made possible by a "non-trained engineer" !!
Have you ever felt like you're "only one" who thinks something ?? I know that feeling well, and I'm going to tell you this: 
Don't worry, you're absolutely on the right track !!

The bearing solution was found "back in the old days", but knowledge of this hasn't fully reached the mainstream. As a result, the seriously out-dated idea still survives among many tuners and engineers that new bearings don't have the right running tolerance, and need to be gently worn in before they fit correctly.

By carefully observing an engine and asking the right questions, we can discover for ourselves that this idea doesn't at all match up with actual observation. 

There has been a long unbroken chain of memorized facts. 
A chain of misinformation can easily survive if no one in the chain stops to think and ask questions.
.

.
A casual look shows that, as the mileage increases, bearing surfaces do appear to be getting polished to a fine fit, or having their tolerances broken-in. 

This would immediately confirm what the experts said. 
End of story.
At this point, a careless observer might say: "That's all I needed to see."

There's no question that the dull gray metal is starting to look
bright & shiny !! 

But, a simple test and observation reveals that:

It's only a coating  that's slowly wearing off
during a certain condition !!

The areas where the coating has worn off are revealing the brighter colored babbit layer metal underneath, which exactly mimics the metal polishing process -- in appearance only !!
..

4 Yamaha R6 rod bearings
with progressively increased use:



#2: Even after the MotoMan's "insane" break-in method, the coating has been 
barely affected. (There are some small scratches on it, but that didn't happen in the engine.)

#3: After a full season of high RPM racing, most of the coating is still there.

#4: Even after 2 full seasons of racing, the most heavily used bearing still has much of its coating !!

..
Here is the same heavily used bearing (#4) pictured above. 
Its thickness is being compared to a brand new bearing (just unwrapped from the package) of the same size specification. 

It turns out that even after 6,000 miles / 9660 KM of constant  acceleration and deceleration from 10,000 to 15,000 RPM, the bearing's measured thickness is exactly the 
same as the new one !!

(The thickness is the "fit" or "tolerance"
described in the easy break-in articles.)

Although these bearings came from a newer engine,
since I started building race engines in 1990, I've never seen
plain bearings with similar race mileage wear to the point 
of a measurable difference from new. 

(There is one exception, and it affects a main bearing of engines of a certain design, as you'll see later on this page.)

As long as the engine is apart, it's a good idea to replace all of the bearings, but it's really not necessary from a 
clearance standpoint.
.

Heavily Used Yamaha R6 
Rod Bearing

.


Brand New Yamaha R6
Rod Bearing

The shiny bearing in the photo on the right looks very "worn", but it's never been in an engine ...

I just wiped it off with a wimpy piece of
Paper Towel !!

This coating isn't like most coatings. It's incredibly easy to remove. I would describe it as a powder.

Please don't take my word for it, buy yourself a main or rod bearing from your favorite vehicle and try this experiment at home. 

You won't believe how easily this coating can be removed until 
you experience it for yourself !!
.

.

" Presto "
Like magic, in less than 5 seconds, the bearing was "polished". Here you can see that when the very top "layer" that gives the "unpolished" look is removed, the metal underneath makes the bearing 
look "polished."

This "layer" is now just residue on 
the paper towel.
.

.
By using sandpaper, and sanding down just until a consistent copper color is seen, we can then measure the difference to determine the babbit layer thickness !!

Of course, destroying the babbit layer does 
destroy the bearing. 
 
(These bearings are both of the same thickness specification.)
.

The bearing on the left is being sacrificed for the sake of science ... it's not going to be used in an engine !!

First, measure the bearing with the babbit layer ...

Next, measure the bearing with the babbit layer removed ...

... then, subtract the difference.

If you own a micrometer, try this experiment yourself !! 

Be sure to clean all the grit off the sanded bearing before measuring it.
Also, be sure to let it cool completely after it's been sanded, or the 
heat from sanding will affect the measurement.

.
For this demonstration, I chose a really thin thing that everyone can relate to -- paper.

A standard sheet of paper is .004 inch / .1mm.

That means that it takes slightly more than 
6 1/2 babbit layers to equal the thickness of 1 sheet of paper !!
.

The softest metal in an engine, the babbit layer, is only 
15% as thick as a standard 
sheet of paper !!
.
.
.
.
Oooooooo ....

.0006 inch/ .015mm isn't just "thin" -- it's Super-Thin !!

.
Clue #1
There are 10 main bearing 1/2 shells, and 8 rod bearing 1/2 shells for a total of 18 in most modern 4 cylinder engines. The first thing that becomes immediately apparent in inspecting this engine, is that by far the most worn bearing out of all 18, is the main bearing indicated by the "X". This is the only bearing in this engine which has worn into the babbit layer. 

(Note: this bearing is located on the right side of the engine. The view of the engine below is upside down from the way the engine sits in the bike.)

This is because in a side mounted cam chain tensioner design, the cam chain is exerting a force 
which is lifting the crankshaft upwards on just 1 end of the crank.
..

Note: this isn't a problem specific to this model, I've inspected 100's of side mounted cam chain tensioned engines from different brands and models, and this same bearing always gets worn far more  than any of the others.

. Here's a close up of the bearing marked "X" in the photo on the left.  If you take a close look at the large version, you'll see that it's darker in the very middle of the worn area. It's actually starting to wear into the copper layer. This bearing definitely needs to be replaced !! ..

Why hasn't this engine failed ??
Because the wear is only happening during a certain condition.
.

The Cam Chain Pull 
VS 
The 15,000 RPM Power Downforce:
 


This photo shows an even better view of the cam chain tensioned main bearing's excessive wear (Left). It's really worn !!

For comparison, one of the lower main bearings is on the right. This bearing experiences the power downforce, yet it's not damaged at all !!

When you use a wrench to turn an engine over with the spark plugs removed, most of the resistance you're feeling is coming from the 
valve springs. It's very easy to do 
on this engine.

You'll also notice that this resistance varies, (it feels "lumpy") depending on where the engine is in its cycle as it's being rotated. The cam chain gets tensioned the most at the peak 
of this resistance.

Now imagine what the force would be like if you were able to hold onto a wrench while this engine is running at 15,000 RPM. 

That comparison puts the forces involved 
into perspective !!
.

How do springs pull up on the crank ??

I sized this photo so that the valve springs in this image are approximately "actual size":



When the engine is stopped, often 1 set of valve springs are trying to push the cam forward. This force pulls up on the cam chain, which in turn 
pulls up on the crank.
The amount of force they pull up with, depends on the point 
at which the engine stops.
 
The cam chain tensioner also contributes a much smaller amount of upward force on the chain. 

I didn't have an R6 cam chain tensioner spring, but this CBR600f3 spring is about the same size, and it exerts approximately the same force as 
the R6 spring does.



 This image is also approximately "actual size".
As you can see by the wire diameter, this isn't a very powerful spring.
. 

Thorvald Sæby

Now, as you can see, Thorvald 
is a man who likes to win. 

So, how did he break the new engine in ?? 

Did he gurgle around at part throttle like most of the other racers who were breaking-in their new race engines that day ??

No Way !!
The engine was warmed up, and moments after the picture on the right was taken, he was accelerating full throttle, shifting at 14,500 RPM through all the gears at one of the fastest tracks in the world ... Daytona !!

One of the most noticeable attributes of winners, 
is that since they aren't influenced by "what everyone else thinks", they don't follow the crowd.
.

The Race Stand:



Jørgen Johnsen of Oslo, Norway's Fast Bikes gets ready to remove the race stand, while Team Yamaha Motor Norway's Thorvald Sæby gets ready to break-in the 2000 Mototune R6.

Although this is a different racebike, the cam chain tensioned worn bearing shown in the 
photos came from an engine which was always parked on a race stand. 


With a race stand, the engine is always level when the bike is parked.

 Hint 1: Main bearings have the same high RPM "oval"
non-contact protection design as rod bearings. The main bearings' housings "oval" at high RPM also.

Hint 2: Gravity is pulling the crank down 
when the engine isn't running.

Hint 3: Sometimes there is less upward pull on the cam chain, depending on what part of the engine cycle the 
engine is at when it stops.

Why are the lower main bearings' coatings only worn in the center, not at the end section ??



(That's curious.)

.
There is no coating wear happening at the "oval" 
high RPM pinch-in  point at the ends of 
the rod bearings either.
.

That's because all of the wear is happening...  
... during a certain condition !!
.

.
When the engine is at rest, the unpressurized oil is often squeezed out by the upward pull of the cam chain.
Again, this depends on the point at which 
the engine stops.

When that happens, the cam chain end bearing looks like figure "A".

When the engine is first started after it has sat for a while, there is a split second of rotation before the oil pressure returns the journal to the normal relationship with the bearing shown in figure "B".

The cam chain tensioned bearing wears due to this momentary rotation when there is a lack of oil between the 2 parts.

(Here again, the oil clearances have been greatly increased to illustrate this concept.)
.

Figure "A"
.

.
The camchain tensioned main bearing to journal relationship when the engine is turned off.

Figure "B"
.

.
The camchain tensioned main bearing to journal relationship when the engine is running.

Removing the coating makes it difficult to see how much a bearing has been used.

It's only wear to the babbit layer 
that's a concern, because that will 
cause problems.

.
These 3 main bearings have had their coatings wiped off with paper towel. This is an extra large photo, so you can see the surfaces close-up. 

1 was heavily used (roadraced), 1 came out of a brand new bike which was only blasted at the factory, and 1 is brand new and was
never used in an engine.

Can you identify the bearings ??    
The answer will be revealed in the next issue.
.

.
Once upon a time in Norway, a tiny plastic bit almost stopped ...

The Mighty
 Budweiser Yamaha R1 !!
.

Brand New 2002 R1 Engine

During assembly at the factory, a nearly invisible stray piece of plastic went unnoticed as it sat on the 
main bearing saddle and the bearing was 
installed on top of it.
.
The seemingly insignificant naughty little bit lifted the bearing enough that the crank wore through the 
babbit layer and was starting to expose 
the copper layer.

This isn't start-up wear, so there was friction being developed while the engine was running. This causes thermal distortion (warpage) and eventually, 
further damage.

But what about:
Oil, like all liquids, is non-compressible ??

The physics haven't changed, it's just that the "container" for the oil is no longer complete, because part of its space is now being taken up by 
the raised section of the bearing.
.

.
This engine was starting to shed bearing layers to become intimate with the crank journal 
while it was running !!



Since this bike was just removed from its crate and hadn't even been ridden yet, the damage occurred at the factory during its initial run. I first got suspicious of a problem when I smelled the faint odor of burnt oil as the crankcases were opened.

Luckily, the soft metal bearing design concept worked, and the crank was unharmed. Rather than replacing a $350 crank, I only had to replace a $7 bearing !!
.

I'm going to pose a question here:
What might have happened if this engine had been purchased by a street rider who 
carefully followed the owner's manual during break-in ??

The answer will reveal one of the best reasons not to do an easy break-in. 

It also reveals one of the real reasons why the factories recommend that you should run a new vehicle gently.

I'll discuss this in the next issue.

Only A Matter Of Time:
Had this engine been raced without fixing this problem, the extreme localized friction and the 
thermal distortion that causes, could have eventually caused the babbit layer to unravel.

The Mighty Budweiser Yamaha R1 
would have been reduced to zero horsepower.

A terrible situation for the racer, engine builder, tuners, fans, and sponsors !

The problem was fixed so that didn't happen, and once we got to the track in Sweden, 
there was a very happy ending to this story ...
.

.

2001 Norwegian Champion André Løwen
Knee on the floor in Sweden on the Budweiser Yamaha R1

 After finishing the first qualifying session in 2nd position for the 
May, 2002 Superbike race at Anderstorp, Sweden --
here's what André had to say: 

" MotoMan ... this is the best race bike I've ever ridden. "

High velocity intake ports, fixed main bearing problem, hard break-in ...
... plus lots more "out of the box" tuning secrets yet to be revealed !!
.

        Ice Cold Bud !!  

.
5 New Techniques For Thinking Outside of the Box: 

1) Use the next door neighbor reading technique with everything you read -- you'll be surprised at what happens. Your real-world intelligence will skyrocket.

2) Don't allow experts to think for you. Observe, test and measure things for yourself.

3) Make mental still pictures to visualize reality.

4) When you've mastered #3, practice making mental moving pictures.

5) Question everything, especially the most widely assumed premises !! 
That's the key to forming truly logical conclusions.




You've got the Power, my friends !!!

What Does The Paper Towel Experiment Tell Us ??

Myths
Myths are born when trusted experts use unscientific methods of study. 
Myths get perpetuated when the public gives up their thinking power to adopt a closed minded memorization of "what everyone else thinks".
Whenever there's a controversial subject, the reason for the controversy usually stems from these 2 factors.

These are the 2 biggest problems in modern science ... and as you'll be discovering, 
these problems affect almost all of the topics of engine tuning.
For this reason, you'll find that most of the topics in upcoming issues of Power News will be very controversial.

Plain bearings don't require break-in, but the power of the myth 
has caused millions of people to think they do.

Teach Others About Engines:
If you read the motorsports internet discussion forums, you've probably noticed that the subject of engine break-in often comes up, and the link to the Break-In Secrets article usually gets posted. The range of opinions about it are extreme. Some strongly agree, while most strongly disagree, but that percentage is starting to turn around.

You can help "break the fake" about break-in !!
Please post the link to this article on your favorite forum.

Opinions and Facts

The difference between a fact and an opinion is very clear -- an opinion is only that, until it is adequately proven. None of the characteristics of bearings are presented 
here as an opinion, they are all easily testable facts.

But here I will present my opinion: 

In my opinion, the method described in Break-In Secrets could have been safely used as long ago as ...
1969
(Maybe Even Earlier)
(In no way has this been proven here yet ... it's only my opinion. But I do have a lot more evidence forthcoming.)

Plain Bearings Are Easily Damaged ... 

... not from a hard break-in, but rather from incorrect installation, debris, oil dilution from fuel*, insufficient oil clearance, oil contamination from blow-by acids*, oil starvation, damaged (rough) crank journal or bearing surfaces, severely overheated oil and abnormal bearing or journal out-of-roundness which causes frictional wear on the high spots.

* Whoops -- I just dropped 2 more hints as to why an easy break-in is really bad for long term reliability.

Without any of those problems, plain bearings are very reliable !!
The key is simply to avoid all of those problems.

In the next issue, I'm going to show my techniques for bearing assembly, 
as well as some common, avoidable reasons that bearings fail.

I'll also reveal some more of my power secrets which helped make this situation happen:

Plus:
That "bottom line" is going to get even longer ... much longer !!



For example: 2 Quotes from the How Long Do You Have To Baby It article:

Point #1 Run it too hard = rings don't seal
" If you push too hard, too soon, the parts will score and scuff each other because the heat generated will be enough to destroy the oil film locally.  A scuffed piston ring doesn't seal. "

Point #2 Run it too easy = rings don't seal
" ... break-in will fail-- usually as a result of such light-duty operation that parts are not loaded together forcefully enough to bed-in to one another.  Rings glaze and fail to seal. "

(These 2 points contradict each other. Also, quote # 1 contains a cause and effect error, and if you think really deep, you'll notice that there's a contradiction within the larger contradiction. 
Hint: it's contained in quote #2.)

The confusion in these statements has in turn led to a tremendous amount of confusion 
among the general public about the process of ring sealing.
I've noticed that there's even more confusion about ring sealing than there is about bearings. 

There are many more problems with these easy break-in articles that I haven't mentioned yet. These will all be covered in future issues along with the ring sealing answers. In the meantime, use the Next Door Neighbor Reading Technique to see how many problems you can notice !!
.

What kind of epoxy are you using for porting ??

I'm happy that there are so many Power News readers are from every part of the world !!
... except Antarctica. 

I'd like to ask for your help:

Many people have mentioned that the type of epoxy I recommended (JB Weld), 
isn't available in their country.

There must be other brands of epoxies that will work for High Velocity Porting. I want to compile a list of epoxies which pass the long term reliability test. Please e-mail me with the other brands of epoxies you've used, and if possible, a report as to the long term reliability of it.

I traveled to the Netherlands to work with a Kawasaki Supersport race team with their ZX6R cylinder head development. In an upcoming issue of Power News, I'll be featuring this team, plus much more about the High Velocity intake and exhaust porting concepts, as well as new information that I've gathered since I first wrote the original porting articles. 

Also, I'm compiling a list of reader success stories about the High Velocity Porting techniques featured here. If you haven't done so already, please send in the results of your efforts !!

" Have a Great Day !! "
... and thanks for all your help !!

Sincerely,
Pat McGivern
~MotoMan