ESE's works engine tuner

[wobbly]

Here is a link to DynoTech,that mentions stale fuel as well.
I have been using the copper tube deto detector into my dyno headphones for years, so as im in a good mood again today here is the detail
on how to do it and why.

http://www.dynotechresearch.com/blog...nYear=2013#294

Nowdays, I like to use the Czech deto box running into the dyno data logger, so i can see at a glance where the deto occurred exactly.

[wax]

Sounds good now if only i could adapt that to my helmet, then again I would most likley be listening so much I would crash.
thanks for the link

[husaberg]

Variable pipe lengths with length or temps
[QUOTE=husaberg;1130093156]
Cagiva ran a system in the "lil Jon" days which extended the header pipe with a hydraulic actuation at huge pressure (1500psi) the pump allowed the header pipe to lengthen along the lines of 20mm extra or minus length .I guess they shorten the header length in operation. If I can be bothered I have pics somewhere.
Of course the Honda water injection based system was much simpler.QUOTE]

You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.

Re adjustable pipes
I know Cagiva ran a Hydraulic system and I think electric is to slow and to thirsty for power.
I also know that Cagiva ran the power valve (YAMAHA Style I guess) and Atac valve on the Randy Mamola bike.

Attachment 249692

I planed at a later stage to use a Greeves (woolley) style labryrinth seals with piston rings to seal the pipes.

My idea was compressed air. Easily rechargeable light nice and simple, super fast and a little goes along way.
I planed to run the Water injection the same way and use excess air in the pipes to reheat it them.
maybe a little fuel if there wasn't enough in the pipes to work it what do you think. I also envisaged using air/electric to trigger the Atac

Bimota did that once: they built a pressurized thin-wall tubular frame with a manometer, so you could scientifically establish when the frame had developed a crack.
Going electric on the movable pipes is not too bad either. I was talking about a Yam TZ500 four cylinder sidecar engine, but for a single the electricity consumption will not be all that much. Here are some pictures to wet your appetite:
Attachment 249693Attachment 249703Attachment 249694

How about a variable exhaust header. This one allows 25mm adjustment

Attachment 241299
Attachment 241300

Google translate says "a new control to include inflammation of RTD and the like" Thanks Google.

Compressed air is rechargeable and simple. I am not so sure about 'light and going a long way'. You might want to do a rough calculation on how much volume at what pressure you consume each time the pipe is moved. That could force you to use a bigger air bottle than you had planned...
A CO2-cartridge could be your way out: I estimate its energy density to be about a hundredfold better than air. Or, what I would do in Holland: use LPG (liquified petroleum gas, or autogas). I don't know whether you guys use the stuff in NZ, but I can get it at every street corner; the pressure is about 8 bar and being liquid its energy density (just talking about the pressure, not about what happens when you light it) is much better than that of compressed air.

Saving that for pulling the slippery pipe.

Frits Overmars

A powervalve does not really give you real resonance power; it just prevents the pipe pulses from completely messing up the power curve at low revs. I expect a sliding pipe will make more low-down power.

http://www.pit-lane.biz/t1666p15-tec...ht=twin+rotary

If you are using an Ignitech then by adding an RZ or R1 powervalve servo means you can program any position you like into a moving slide or rotary "timing changer" - easy.
Having a movable "slide" in behind the closing edge of a rotary valve, pushed/pulled into position by servo cables, would be easy and reliable. Get on with it.

I was just pointing out that the idea of using water, great as it may be in theory, and on a dyno when looking for bottom end, it "works" just fine.
But in a controlled test to see if its was useful, it failed, as the systems effect had to be reduced so much that any gain in bottom end was still offset by a loss in the top end.
As Burgess said, when the effect was useful, it took too long to reheat the pipes.
My thoughts, from the testing I did with a PV and ATAC operated separately ( instead of combined together as many MX engines have now) is that this works real well with no down sides at all,and is easy to implement.

OK, here is some info on how to utilise the servo option on the Ignitech.
The servo has 5 wires, two are 12V +/- and the other 3 are the servo feedback positioning pot.
Always wire the two functions on separate plugs. Once you have the servo connected to the blade or whatever, disconnect the servo motor power plug.
Then on the screen you will have a readout for the servo position, as mV or as a % if using the RACE box.
I have never used the % option so here is how to program the mV setup. Drive the servo to the travel limit ( in, or down or whatever) by gripping the servo wheel with vise grips.
Cycle it back and forth a few times to get an accurate position that takes up any small slack in the cables.
Note down the "servo measured" value on the screen. Then wind the servo around to the opposite limit, note this value down.
Then in the servo screen you can enter the two values of fully up, and fully down, with an rpm span between them.
Use a few of the extra points in between, so you can, if needed, force a non linear movement with rpm ie not a straight line.
Hit program, turn off the ECU, turn it on again, and it will cycle up and down,as it has been programmed.
You can check the up and down positions and compare the "servo measured" to the "servo desired" on screen, in real time.
The hysteresis should be set usually at around 100mV, less will speed up the response, but go too low and the servo will "hunt" around the values programmed.
The RZ servos are all getting old and shagged - the newer R1 servo is mechanically very similar but uses a special molded in plug - I have the right ones to match.
The R6 and ZXR ones are not as well made, the shaft isnt supported at both ends properly.
Here is a sample wiring setup and a PV curve, set to start opening at 7200 and full open at 9000, with about 1V of span between.
You could use this to rotate a spool like an RZ, a blade like a flat PV or even the 1/2 throttle plate if you wanted to.

Something to think about while the rest of the family occupy themselves with buying, boiling, painting, hiding, searching, finding and eating easter eggs: a couple of recent videos from the Dutch 50 cc scene.
http://www.youtube.com/watch?v=mvV4x...feature=relmfu
http://youtu.be/0odVzSgufjk

It was designed and built by Richard Maas http://www.adriaanmeeuwsen.nl/team-pagina.html. Hopefully we will see it in action next monday.
And if I were you, I would make it go shorter with rpm .

I'm impressed with how it slips all nice and steady!

Frits, may I ask, wouldn't it affect the 1st pressure wave in the diffuser, when fully inserted? -in a way to have a measurable impact on pipe effects I mean

You may. It will affect all the waves in the pipe. And it does have a measurable impact on pipe effects .
But I suspect you are referring to the header intruding into the diffuser. It doesn't. Even in the shortest position everything is smooth inside the pipe.

More news from Richard Maas. Did his trombone pipe give the desired results? O yes. At 10,000 rpm it gives 4 HP more than the same engine with a fixed pipe. It runs over 17,000 rpm without the need for a powerjet and with a fixed ignition timing. It is miles better than an engine with an exhaust power valve. And the mapping of pipe length, ignition timing and powerjet pulse width has yet to be carried out. Maybe the powerjet can disappear altogether.
Only problem so far: the piece of pipe that is fixed to the cylinder, is shrouded by the pipe that slides over it, so it gets very hot. Too hot for the Viton O-ring that is taking care of sealing. Any bright ideas, anyone?

I came upon this today.

Slippy exhaust pipes
Why they're so difficult to pull, and how to fix it...
There has recently been a thread on the Mailing List in regards to the amount of effort required to "pull" the typical slippy (adjustable) exhaust pipe that is common in many road racing classes.
Well... A bit over 20 years ago, I had the same frustration, and I'll explain what I found, and how I solved the problem.
The image below show's an approximation of a "typical" slippy exhaust pipe. I have not shown the outlet hole in the "can"... (and a number of other things are missing as well), but this will serve the purpose for now. The moveable rear (convergent) cone is shown in its "out" position by the blue lines... and in it's fully "in" position by the green lines. The thick magenta line is a rough representation of the cable which pulls the rear cone/stinger assembly.

OK... here's the problem in a nutshell: The amount of effort required to "pull" the rear cone is directly proportional to the difference in pressure between the front and back sides of the moveable cone. (There's some other minor things like friction, but they're insignificant compared to the pressure differential).
Since the the rear cone (at its big end) does not fit the large center section perfectly, some "pressure" leaks by the outside of the cone into the area behind the cone. If the outer rear cone (the one that supports the stinger) has too much clearance on the stinger (where I wrote "Here's the problem"), then the pressure behind the rear cone can "bleed" into the can (which has lower pressure than the inside of the exhaust pipe). This results in a pressure differential between the front (engine) side of the rear cone, and the back side.
THAT is what you are pulling "against" when you try to pull in your slippy pipe.

Now here's how I fixed the problem...
Years ago, Hartman Engineering made some very nice spun "outer" rear cones especially for slippy pipes. I started with one of those. They were made with a very large hole on the small end. (Oh... the other thing that was really nice about those Hartman cones is that they were very short. This allowed you to get the weld to the center section a long ways away from where the adjustable cone would be sliding.... which made it easier to keep the center section nice and round).
I made an insert for the small end of this cone (shown in red in the drawing below). This "insert" had a bit of a "bell-mouthed" shape to the inside diameter. I did this so that I could run a very tight fit to the stinger, without the stinger "binding" due to any misalignment that might exist. I also took the stinger material (before welding it to the cone) and had it hard-chromed, and then ground the outside diameter. This made it perfectly straight and round, as well as giving me a super fine finish that would resist any sort of galling or seizing. I gave the insert about .005 clearance on the stinger (as I recall).
How did it work?
Too well. At the time I was running Open class. Due to the power, Open engines were notorious for being almost impossible to pull the exhaust pipe for the full race (an hour long at the time). My first time on the track with this pipe was a complete surprise. The very first left-hand sweeper I went through, the rear cone went all the way in by itself, just from cornering force! The pipe was actually far too easy to pull. My solution was to experiment with "vent" holes into the can. With the clearance that I had given the stinger in my "support sleeve"... as well as the fit of the large end of the cone in the center section of the pipe... I ended up running a 3/16" diameter "bleed hole" from the outer rear cone (the short steep one in the drawing below) into the can. This gave just about the perfect "feel" in my case. I could operate the pipe handle with one finger... yet there was enough pressure on the cone to move it back out fairly quickly when I let go of the handle.

You may not care to build your own slippy pipe... and we're seeing less and less classes where slippys are allowed... but hopefully this might help some of you that still run them.
Just remember: the effort required to pull the rear cone is directly related to the pressure differential on the front and back sides of the moveable cone. Anything you can do to prevent leakage around the stinger and into the can will make the pipe easier to operate... up to the point (I discovered) where it's too easy.

There are several options in lengthening a pipe. You can move the end cone, like on the above drawing, or you can lengthen the header, like on the trombone pipe.
The gas pressure generates a force that is proportional to the cross section area of the moving part and proportional to the pressure difference at either side of that area. For a moving end cone this force can be up to 4 times larger than for a sliding header. That is one reason to go for the trombone system rather than the moving cone system.

The second reason: say you wish to lengthen the total length of the pipe by 10 %. If you do it by moving the end cone, you will also enlarge the pipe volume by a little over 10 %.
But in a good pipe configuration the header length is about 1/3 of total pipe length, so in the trombone system, lengthening the pipe by 10 % will result in lengthening the header by about 30 %. That gives a far greater variation in the pipe's Helmholtz frequency than a 10 % volume change.

It is true that the length percentages of all pipe components should be in a rather fixed relation to each other. Varying the lengths of all components by the same percentage would be the theoretical optimum, but that is not feasible.
Lengthening the belly will disturb the optimum relations, as will lengthening the header. So the pipe in its lengthened version will not be the optimum for the low resonance rpm dictated by the length. But it will be a hell of a lot better than using an exhaust power valve that spoils the 180° effective exhaust timing, necessary for true resonance.
And a pipe shortened beyond its optimum may not show the optimum length relations between its components either, but it will be a lot more effective in overrev than artificially raising the exhaust gas temperature by retarding the ignition, or by weakening the mixture strenght through closing a power jet, which has the disadvantage that not all inhaled air is used for combustion.

Slippy exhaust pipes

I was having a quick look at some old posts and re-discovered this from F5 Dave about adjustable length expansion chambers. It has to be a good idea, if it could be automated to work by itself even better. Now how to fit it onto my bike?????????????

From an Add for a RC Car exhaust:- The precisely engineered components of the Power Exhaust System use the unique exhaust pressure characteristics of 2-stroke motors to dynamically adjust the tuned length of the exhaust system. This is why Power Exhaust Systems can achieve maximum performance over a much wider RPM range than is possible with a fixed pipe. Changing of the tuned length is accomplished by the movement of the internal Tuned Assembly within the Power Exhaust Body.

While traditional tuned pipes focus on only one RPM range for maximum effect, the Power Exhaust System can boost performance throughout the entire RPM range. It’s (possibly) the world’s only tuned pipe that dynamically adjusts its tuned length during use.

"Tuned length" refers to the total combined length of the exhaust header and tuned pipe from the face of the piston to the end point of the convergent cone. This is the factor that is generally calculated first in pipe design. The tuned length is a function of certain fixed engine parameters and more significantly, a target RPM for maximum performance. Of course, a designer can only choose one target RPM. One RPM equals one best-tuned length. For a maximum benefit over a greater range of RPM you must change the tuned length.

F5 Daves might be better because only the rear cone moves but the RC Car pipe shows how it could be automated.

Pic-1 from F5 Daves post

Pics-2 to 4 is how RC Cars do it.

.

[QUOTE=TZ350;1129291117].

"Tuned length" refers to the total combined length of the exhaust header and tuned pipe from the face of the piston to some point on the convergent cone. This is the factor that is generally calculated first in pipe design.

Danger Danger Danger There are two common ways that the term "Tuned Length" is used. Some people think tuned length is measured to the end of the convergent cone others measure tuned length to the mean reflective point half way along the cone. Thats half way along the complete cone with its pointy bit still on the end.

When talking about/compairing/calculating tuned lengths you need to know how the "Tuned Length" is being defined. Its an important difference, about 50-80mm or 1,000 to 1,500 RPM and can completly confuse your tuning efforts.

I am indebted to Thomas for pointing this out to me.

He also says that the sum of all the individual stages (cones) in Pic-1 should more correctly be called the overall length, and the overall length is most certinaly not the tuned length given by most/all formulas that you see for calculating the tuned length of an expansion chamber.

Most/all formulas for tuned length based on time and the speed of sound give a value for the length from the piston face to the mean reflective point of the convergent cone (Pic-2) and this is correctly called the "Tuned Length" because this is the mean distance/time the pressure wave travels out and back in the pipe.

Pic-1 Tuned Length. "tuned length measured to the end of the cone"

Pic-2 Tuned Length. "tuned length measured to the mean reflective point of the cone"

Pic-1 is wrong and Pic-2 is right as the "Tuned Length" is the mean distance/time the pressure wave travels out and back in the pipe.

It's been done before in bucket racing, Peter Steadman. The end cone was slid back and forth by a servo, possibly a central locking solenoid. It had a cable pulling it in each direction. Remember Peter's bike has the stinger exiting from the centre section. I'm not sure why it wasn't persisted with. His bike was pretty quick without it so maybe it just wasn't worth the added complexity.

I had a bit of a quick squizzy at The effects of crankcase volume on the delivery ratio:-
http://www.edj.net/2stroke/jennings/...ase_volume.pdf & must admit I'd never heard of the test engines. Then noticed they spin out to the dizzy heights of 4500rpm at best. One can imagine that the pressures involved are not proportional compared to time areas due to gas flow at up to 3x the revs.

ok here's one to send people down the garden path with a nice but difficult idea
http://www.muller.net/mullermachine/docs/slippy1.html

Borut makes Zeeltronics stuff for mainly RGV, NSR etc but could be possible to adapt to a bucket but you'd have to talk to him, you need 3 boxes to get programmable & will cost a site more than 100 euro. (I have a setup on my 500).

Pipe design elements relating to variable with pipes

If I were to explain pipe design I would need to write a book,but in general things are pretty straight forward in relation to the % values.
End of header is always 31 to 33% and end of diffuser is always 62 to 68%.
To see the effect of a silly long header, you can watch the pressure ratio at the Ex port, and thus the effect this has on the depression in the cylinder.
We are looking for the lowest and widest negative ratio we can get around bdc when the transfers are fully open.
A long header delays the beginning of the depression too late in the cycle, when in the power band.
In a race 2T we are always fighting power range Vs peak power.
Shorter diffusers create steeper angles,thus greater wave amplitude, but this narrows the effective band width.
So - in general the best compromise is around 66%.

The % I quoted for header means that portion of the length from piston to rear cone end.
Its from the piston to the beginning of the diffuser, what happens in between isnt relevant.
Unless of course you use a small Ex duct and a bigger header, that makes more power.
And of course same for the diffuser end, that is simply 66% of the length from the piston to the end of the rear cone.

Frits Overmars

A powervalve does not really give you real resonance power; it just prevents the pipe pulses from completely messing up the power curve at low revs. I expect a sliding pipe will make more low-down power.

http://www.pit-lane.biz/t1666p15-tec...ht=twin+rotary[/QUOTE

Imagine the valve passes 60 cc of fuel per minute, but the engine only needs 30 cc. How would you go about that? You could open the valve for 30 seconds and then shut it, but by that time the engine may have drowned.
Open it for one second, close it during one second, open it for one second, sounds more sensible, doesn't it? That is why I quoted the valve's frequency: 13 Hz.
That means it can open and close up to 13 times per second. This again means it could open for 1/13 of a second and close the rest of the second, or open for 12/13 of a second and close during 1/13 s, or everything in between. And of course it can stay completely open or closed; enough possibilities to govern the mixture.

The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.

You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.

[husaberg]

Oh i missed this one Frits

Water injection into exhaust pipes in order to lower the exhaust gas temperature and thus the system's resonating frequency has been tried over and over. It works, but it does nothing to protect the engine from detonation.
Therefore I wanted to inject water into the combustion chamber, exchanging temperature for steam pressure. I even had a water reservoir designed around the exhaust tail pipe in order to heat the water to just below its boiling point before it was injected.
I also tried to hit the piston crown with the injected water but a steam cushion would form, preventing most of the water from wetting the piston crown. Breaking through that steam cushion would require a huge (for that era) pressure and a very thin water jet, or the engine would drown. I could not get it realized back then (in 1992, when I was working for Rumi) so there are no test bench data.

[Frits Overmars]

I was dreaming late last night ( about 2Ts - what else ) and thought thru the statement that Frits was questioning ( a complement to a very skilled bullshit detector that man I must say ).
Maybe the logic of " unvapourised fuel only displaces O2 in the combustion process " leads to the Ex gas then also being low in O2 so the Lambda reads rich ?
I dont know to what extent ie what % of O2 can be displaced by fuel that is never burnt, and if that level is then sufficient to affect the Lambda reading.
That then leads me to the question - wouldn't a continuously misfiring engine read rich on the Lambda, and isnt that then the same end result as unburnt fuel droplets passing thru an engine?
This is too early in the morning for this - I need strong coffee.

I hope you had that coffee, Wob. And as you are ten hours ahead of me, I suspect you are sipping something tastier by now.
First let's look at the 'logic' of unvaporized fuel displacing O2. The fuel is carried into the combustion chamber by the air; air and fuel are in there together and there's no way that the air could be forced away by unvaporized fuel droplets.
Unvaporized droplets won't be doing much forcing anyway because the volume of an unvaporized droplet is about a thousandfold smaller than the volume of a vaporized droplet.

Wob, detecting bullshit is quite easy if you produced that bullshit yourself in the past.
I once ran an engine on the test bench and the Lambda sensor said 'lean', or so I interpreted it at the time. So I jetted up.
Then the Lambda sensor said: 'now it's even leaner!'
What really happened was: at the first test the engine was so rich it was misfiring. And no combustion meant: unused oxygen in the exhaust gas.
Naturally when I jetted up, the misfiring became worse, even more combustion cycles failed and even more unused O2 hit the Lambda sensor.

Lesson learned: a Lambda sensor does not say 'rich' or 'lean'. All it says is: I see ogygen'.

[husaberg]

First let's look at the 'logic' of unvaporized fuel displacing O2. The fuel is carried into the combustion chamber by the air; air and fuel are in there together and there's no way that the air could be forced away by unvaporized fuel droplets.
Unvaporized droplets won't be doing much forcing anyway because the volume of an unvaporized droplet is about a thousandfold smaller than the volume of a vaporized droplet.

Wob, detecting bullshit is quite easy if you produced that bullshit yourself in the past. I once ran an engine on the test bench and the Lambda sensor said 'lean', or so I interpreted it at the time. So I jetted up. Then the Lambda sensor said: 'now it's even leaner!'
What really happened was: at the first test the engine was so rich it was misfiring. This meant no combustion, so unused oxygen in the exhaust gas. Naturally when I jetted up, the misfiring became worse, even more combustion cycles failed and even more unused O2 hit the Lambda sensor.

Lesson learned: a Lambda sensor does not say 'rich' or 'lean'. All it says is: I see ogygen'.

I was going to say something similar but only cause it was in a book i read today.......
Where as you thought of it cause you understood.......
forgive Cameron he was talking about 4 strokes though
http://books.google.co.nz/books?id=J...20port&f=false

Can you tell us about the steam in cylinder experiments Frits?

Also if i can be so bold i was lloking at a pic of a RSW or RSA crank the other day and it seemed to have what looked like Brass rings around the Crankpin pressed in the crankcheeks?
Is that what they are? and why are they there?

[Frits Overmars]

.... forgive Cameron he was talking about 4 strokes though http://books.google.co.nz/books?id=J...e port&f=false

Anything Kevin Cameron writes is worth reading.

Can you tell us about the steam in cylinder experiments Frits?

Only what I wrote above: that there were no test results, for the above-mentioned reasons.

i was lloking at a pic of a RSW or RSA crank the other day and it seemed to have what looked like Brass rings around the Crankpin pressed in the crankcheeks? Is that what they are? and why are they there?

Yes, that is what they are (well, not brass but bronze) and they are there to reduce axial friction between the con rod and the crank webs.

[wobbly]

Amazing Frits how complex logic can get, and more amazing that in reality its all simple when you finally get to understand.
Of course Lambda only reads the O2, what a dumb shit.

Anyway more importantly I have now for the first time seen the inside face of an Aprilia crank.
Apart from the bronze ring ( does that replace a silver plated washer ? ) I now see a huge amount of inserts in the crank face.
These you dont see in the many pics that show a ton of what is obviously Mallory around the circumference increasing the rotational inertia.
I assume the inserts on the inside are filled with lighter material ? in the pic I cant tell if its alloy or even more Mallory heavy metal.

[peewee]

wobby sorry i dont hang around much. you know what the best drag pipes are for a banshee ? probly use some ported stock cylinders. might use some cubs if its in the budget but its not looking like it. was kind of looking for a challenge to see how good i can make the stockers run and it wont cost a ton of money

[2T Institute]

Amazing Frits how complex logic can get, and more amazing that in reality its all simple when you finally get to understand.
Of course Lambda only reads the O2, what a dumb shit.

Anyway more importantly I have now for the first time seen the inside face of an Aprilia crank.
Apart from the bronze ring ( does that replace a silver plated washer ? ) I now see a huge amount of inserts in the crank face.
These you dont see in the many pics that show a ton of what is obviously Mallory around the circumference increasing the rotational inertia.
I assume the inserts on the inside are filled with lighter material ? in the pic I cant tell if its alloy or even more Mallory heavy metal.

This was discussed on the Aprilia FB page Wob, not sure if it was Jan or Thijs that said it was tungsten with a magnesium cap. Thrusts are still there.

[husaberg]

This was discussed on the Aprilia FB page Wob, not sure if it was Jan or Thijs that said it was tungsten with a magnesium cap. Thrusts are still there.

Its something that has been revolving in my mind as they are cracked... they seem to be actually pressed in the full distance of the pin rather than a thrust washer insert replacement? there def seems to be an full insert (steel looking inner one at that on the left side picture)

[WilDun]

Its something that has been revolving in my mind as they are cracked... they seem to be actually pressed in the full distance of the pin rather than a thrust washer insert replacement? there def seems to be an full insert (steel looking inner one at that on the left side picture)

I would doubt very much if that's the case as bronze might be good bearing material but probably not as good as steel to carry the load and help hold the pin against rotation (differential expansion rate and all that).

What interests me most is the placing of the balance plugs, - this picture gives me the notion that all the light plugs appear to be the smaller ones and the heavy plugs are the larger ones.
If you look carefully at the left picture (lets say the crank is at 3 o'clock, the two smaller lighter plugs are grouped together at around 5 or 6 o'clock and the three larger plugs (heavy ones?) grouped together are at about 10 o'clock. - clear as mud? - maybe that's how it normally is these days, I dunno.
No doubt someone can correct me if I'm a bit behind here.

[Ocean1]

Its something that has been revolving in my mind as they are cracked... they seem to be actually pressed in the full distance of the pin rather than a thrust washer insert replacement? there def seems to be an full insert (steel looking inner one at that on the left side picture)

Think what you're looking at there is the result of the needles trying to escape the rod.

In fact there's plenty of evidence that the rod's been trying to escape the crank...

[Frits Overmars]

The bronze rings are only about 2 mm thick. Their advantage over the usual thrust washers is that they can get rid of friction heat easier and won't vibrate themselves to pieces.
The combination of Mallory slugs and hollow light-alloy caps serves to combine a low total mass of the cranks with a high inertia that made the 250 cc twins more rideable. The same setup was used for the 125 singles, but as Jan Thiel said: 'In seven years of experimenting we have not been able to establish what is best: high or low inertia'.
My approach: when in doubt, choose low; it will be a blessing for the transmission and the rear tire.

[husaberg]

Think what you're looking at there is the result of the needles trying to escape the rod.

In fact there's plenty of evidence that the rod's been trying to escape the crank...

SO the ring shape about 4mm larger than the crankpin is only witness marks.... from the rollers....