ESE's works engine tuner

[SwePatrick]

I can´t see the reason why one would like to aim more gasses in the rear of the cylinder against the exhaust?
As 'normal' with a hook, you got mainflow against eachother with the B ports.
And the hooks helps flip up the gasflow upwards to make it easier for the C port to lift it up.

[adegnes]

I can´t see the reason why one would like to aim more gasses in the rear of the cylinder against the exhaust?
As 'normal' with a hook, you got mainflow against eachother with the B ports.
And the hooks helps flip up the gasflow upwards to make it easier for the C port to lift it up.

But with slightly different wall angle as I mentioned maybe? Aim them more towards the C port to make up for the lost hook and make them less prone to shoot straight out the exhaust.

[teriks]

Pretty much exactly like this:

<SNIP>

Well, a later design is not as radical on the B ports.
Is the newer design better? -I have no idea..
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[peewee]

I would think that a B-port designed as Adeg is suggesting would cause less trapping efficiency. I would think that the port's speed would be on the high side causing more mixture to be lost to the Exh port, but then again on the reverse pulse from the pipe, the stronger stream may mix less with the exhaust and purity might go up? As Adeg has said, my common thinking has been proven wrong multiple times on these 2 -strokes.

Wobbly, you are saying that the port 'with NO hook' had better trapping efficiency?

a hook is like what honda did for so many years on dirt bikes. cr500 is good example. yamaha banshee is another. its old school and crappy but back then i guess nobody cared. i think what wobbly said is the radius back wall like most any modern cyl works much better than stone age honda hooks

[katinas]

After testing KTM SX 50, the results showed, that maybe rounded piston bigger radius (with sharp edge at C), requires little bit bigger ex. stinger area. Maybe is some coherence between radius and stinger dimensions, but we need more tests.

In theme about head inserts.
Very interesting, after our discussions about head insert alloy, last week I had call from one MX sixteen years girl's mother, to help about cracked VHM insert on their KTM SX 125, because before the last race she was leading in 125 class, just only boys around and new head can be arrive only after race.
Crack was in the middle of the sphere, aprox 20mm long, directly at water outlet side (sorry not made photo) and squash band with easy detonation sign. Made new insert from 2618A alloy
Last weekend girl won championship, first time in our country MX championship history.

[Ocean1]

Possible stupid question.

Isn't it likely that port shapes found optimal for small engines are not optimal for higher displacements?

How similar are the respective flow velocities? Are there likely to be differences related to boundary flow ratios?

Or are demonstrably ideal 50cc port details going to be able to plug directly into that CR500 with proportionately improved results?

[Frits Overmars]

After testing KTM SX 50, the results showed, that maybe rounded piston bigger radius (with sharp edge at C), requires little bit bigger ex. stinger area.
Maybe is some coherence between radius and stinger dimensions, but we need more tests.Hopefully there is some coherence between radius and power, and there is definitely a coherence between power and restrictor size.


Isn't it likely that port shapes found optimal for small engines are not optimal for higher displacements?
How similar are the respective flow velocities? Are there likely to be differences related to boundary flow ratios?
Or are demonstrably ideal 50cc port details going to be able to plug directly into that CR500 with proportionately improved results?I'd say that port shapes are scalable between engines with identical bore/stroke ratio and identical piston speed.
Boundary layers are not scalable, but this influence should be moderate, provided the dimension ratios between the big and the small engine are not extreme.
The proportions between a CR 500 and a 6,5 cc engine are extreme, but I expect that there'll be a reasonable scalabily between a CR500 and a 50 cc engine.
Which is not to say that you should try it: 50 cc-like tuning will turn a CR500 into an unrideable beast.

[katinas]

Hopefully there is some coherence between radius and power, and there is definitely a coherence between power and restrictor size.




Yes, with rounded piston on SX 50 first time engine overcome 14 hp and graph is higher everywhere in rpm range, but only after little bit bigger ex restrictor, not like with SX65/85 when roundness work immediately without any changes.
So, engine power, at some point with smaller restrictor, can be worse with rounded piston edge than with sharp.

[lohring]

Hopefully there is some coherence between radius and power, and there is definitely a coherence between power and restrictor size.

I'd say that port shapes are scalable between engines with identical bore/stroke ratio and identical piston speed.
Boundary layers are not scalable, but this influence should be moderate, provided the dimension ratios between the big and the small engine are not extreme.
The proportions between a CR 500 and a 6,5 cc engine are extreme, but I expect that there'll be a reasonable scalabily between a CR500 and a 50 cc engine.
Which is not to say that you should try it: 50 cc-like tuning will turn a CR500 into an unrideable beast.

I think friction effects, especially piston friction, overwhelm other considerations in really small engines. Except for Frits' design, most Schnuerle ported model engines have 2 or 3 transfer ports with the poorest passage designs. Maybe boundary layer effects are starting to restrict flow with the small passages in 5 transfer designs. Really small engines (as small as .01 cubic inch or .16 cc displacement) use an opposed exhaust with opposed transfers. Their success can be attributed to the high precision piston and cylinder manufacturing process.

Lohring Miller

339175

[jonny quest]

https://m.youtube.com/watch?v=qQFx1jmgiic

Plasma spark hack

[adegnes]

https://m.youtube.com/watch?v=qQFx1jmgiic

Plasma spark hack

So basically a very small cap in parallel with the sparkplug, larger cap value makes it more "fierce".
Like a spark gap protection circuit.
Does it contain more energy though, or is it just sparking multiple times after each main event as the cap reaches high enough voltage?
Must add that I have no clue...

[F5 Dave]

. . .
The proportions between a CR 500 and a 6,5 cc engine are extreme, but I expect that there'll be a reasonable scalabily between a CR500 and a 50 cc engine.
Which is not to say that you should try it: 50 cc-like tuning will turn a CR500 into an unrideable beast.
You just know of course that a certain, rather large portion, of readers were breifly excited and entertaining this idea;)

Some longer than others.
Some mentally adding additional cylinder banks:banana:

[Ocean1]

I'd say that port shapes are scalable between engines with identical bore/stroke ratio and identical piston speed.
Boundary layers are not scalable, but this influence should be moderate, provided the dimension ratios between the big and the small engine are not extreme.
The proportions between a CR 500 and a 6,5 cc engine are extreme, but I expect that there'll be a reasonable scalabily between a CR500 and a 50 cc engine.
Which is not to say that you should try it: 50 cc-like tuning will turn a CR500 into an unrideable beast.

So, if capacity isn't constrained, is just another tuning variable within an open racing class then where is the likely optimum capacity point?

If any one of the current capacity limited racing classes had that constraint removed then what would the trend be? Towards slightly larger engines based on similar tuning factors because it's easy power with few comparative disadvantages, or towards significantly more capacity with all of it's associated mass issues and likely tuning discrepancies but hugely flexible power?

Or does that depend entirely on the track size and surface? Case in point: I think the difference between 250 and 400 MX lap times are negligible, more dependent on minor track variations than available power, and I think from track to track the respective advantages for each is close to 50/50.

[Ocean1]

You just know of course that a certain, rather large portion, of readers were breifly excited and entertaining this idea;)

Some longer than others.
Some mentally adding additional cylinder banks:banana:

But we're more excited by the intellectual exercise than the vulgar prospect of vast quantities of unseemly torque.

Aren't we?

[adegnes]

But we're more excited by the intellectual exercise than the vulgar prospect of vast quantities of unseemly torque.

Aren't we?

Indeed.
......

[Larry Wiechman]

But we're more excited by the intellectual exercise than the vulgar prospect of vast quantities of unseemly torque.

Aren't we?

Ironic quote from a KTM 1290 SDR rider.

[Frits Overmars]

So, if capacity isn't constrained, is just another tuning variable within an open racing class then where is the likely optimum capacity point?
If any one of the current capacity limited racing classes had that constraint removed then what would the trend be? Towards slightly larger engines based on similar tuning factors because it's easy power with few comparative disadvantages, or towards significantly more capacity with all of it's associated mass issues and likely tuning discrepancies but hugely flexible power?
Or does that depend entirely on the track size and surface? Case in point: I think the difference between 250 and 400 MX lap times are negligible, more dependent on minor track variations than available power, and I think from track to track the respective advantages for each is close to 50/50.You had me thinking about road racing until your last sentence directed me towards agricultural racing.
In MX the power of a 400 cc or 500 cc bike is probably more than you can use on most tracks. What you can improve with more cubic capacity is rideability: no power band as such, but always sufficient good-natured, finely-doseable rear wheel torque without the need for gear shifting or clutch fiddling.
Half a lifetime ago I tested the Husqvarna 400 Automatic (3-speed with centrifugal clutches; later they also built a 4-speed along the same lines). It made me a much better dirt rider. In other words: the concept worked.

Improving rideability is also what the boys in MotoGP are doing: far too much power that's only good for long straights (Mugello) and a complicated Engine Control Unit to keep the rider alive.
The FIM in its immeasurable wisdom decided that the sport was becoming too expensive if every constructor developed its own ECU, so they all had to make do with the Italian Marelli ECU. Honda threatened to withdraw from racing altogether if this decision wasn't revoked, but in the end they went along. Ducati was happy because they were already cooperating with Marelli. Yamaha suffered, and is still suffering: they can't seem to come to grip with the Italian ECU.
Now everybody is experimenting with spoilers in order to keep the front wheel on the ground. It's not a development I applaud.
I'd like to see a nice victory wheelie whereby the wind gets under those spoilers and turns the wheelie into a backflip :devil2:.
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[Ocean1]

Now everybody is experimenting with spoilers in order to keep the front wheel on the ground. It's not a development I applaud.
I'd like to see a nice victory wheelie whereby the wind gets under those spoilers and turns the wheelie into a backflip :devil2:.

There's probably a solution to be found lying around the aviation industry somewhere, but I suspect the need for that solution indicates that you're no longer operating a motorcycle.

As for the capacity variable, I spent a bit of time playing with machines denied that option, and I did find that the lack of development in that direction detracted from my understanding of the benefits to be had, there. So when I started playing with bikes with little or no constraints I was delighted with what was available from simply minimising mass and maximising capacity.

From a dirt riding perspective I'm interested in your experience with that automatic Husky. With that capacity and tune and a well tuned auto I would imagine traction would be somewhat enhanced, and I'm wondering if most dirt rider's typical use of power to selectively reduce traction as a control tactic is a genuine advantage in a traditional dirt bike, or if it's simply making best use of a less advantageous feature.


Ironic quote from a KTM 1290 SDR rider.

Yes, the SDR rider is aware that several on board computers are often of the opinion that his request for more power should be denied. You can tell, the dash lights up, and you're not dead.

[Larry Wiechman]

Yes, the SDR rider is aware that several on board computers are often of the opinion that his request for more power should be denied. You can tell, the dash lights up, and you're not dead.



The SDR is my first experience of only having a vote, not the final say, on throttle opening percentage. Experiments with turning the Motorcycle Traction Control off have resulted in profanity flowing like poetry.

[Ocean1]

The SDR is my first experience of only having a vote, not the final say, on throttle opening percentage. Experiments with turning the Motorcycle Traction Control off have resulted in profanity flowing like poetry.

SuperMoto mode. :niceone:

[Muhr]

Regarding previous discussions, I think I would give the opportunity for further discussion with the following statement.
The only state of motion the gas flow has is that it is pushed and thus completely dependent on what is happening behind to be able to be pushed into an area with lower pressure, by the atmosphere or local atmosphere (closed crank compression).

[peewee]

wob about the aux windows extending into the wristpin cavity . have you ever tried to determine any power increase from extra sta vs any power loss from short circuiting ? assuming a tear drop shape to keep short circuit small as possible , along with good aux passage geometry

[SwePatrick]

Regarding previous discussions, I think I would give the opportunity for further discussion with the following statement.
The only state of motion the gas flow has is that it is pushed and thus completely dependent on what is happening behind to be able to be pushed into an area with lower pressure, by the atmosphere or local atmosphere (closed crank compression).

Don´t forget speed and the increasing inertia that follows speed.

[SwePatrick]

My 211cc kawasaki project?

I had a lot of issues.
Carb is shaking hard and foaming fuel, have been designing a balance shaft system, it works, but need to sent away to get hardened.
It broke the cylinder, the deckplate came loose, have been strengthening that, it works now.

So today i was curious if the new cylinder and pipe produced any power as it sounds amazing, no balanceshaft mounted as i don´t want to run the gears without heat treatment.
Yes, still have issues with foaming, but in the dynopull below i reached for the carb with my left hand and hold it to dampen the vibrations.
You can see on the curve, a huge dip, it started to make power instantly when holding the carb.
But,,,, either the clutch started slip hard or the tire spun on the roller, or both.
After the pull the reartire was quite hot.

Last year a pull took about 7seconds starting at 8000rpm and up to 13200rpm, this when producing ~68hp to the roller.
This year a pull took 2.97seconds starting at 8000rpm and up to 13200rpm(the same) but only produces 50.95hp
Datalog from dyno shows about ~150% slip at where peak power should be, 12600rpm

But in all the disaster i still see some light.
more traction and more weight on the clutch should do the trick.
I´m aiming for about 70hp to the roller

http://forumbilder.se/H8D5D/spin.jpg
http://forumbilder.se/H8D5D/crack.jpg

[wobbly]

There is a direct relationship between the available STA/power increase by extending the Aux around to the bore center , but its how you implement this that sets the
amount of port linking and thus the amount of short circuiting.
Assuming no pin plugs its a very tricky compromise.
The solution is two fold, one is the teardrop shape , this adds area at the top of the port where the pressure delta is the greatest , and thus the flow.
Then the second element is the depth of the Aux port " pocket " if you like at the top corner near the bore center.
Ideally a nice big deep radius would seem to be the best way to add flow , but all this does is dramatically increase the linking area , and the trade off is badly in favor of short circuiting reducing the trapping efficiency
and thus power.
So you juggle the height of the port at bore center, and make its exit into the duct all but tangent to the bore thus keeping the linking depth to a minimum.
This makes the best compromise and the best power with no plugs.

Re the previous question about B hooks - the radiused hooks Cd is so hugely superior that it always seems to make more power even keeping the same directional exit angle.
The optimum angle may in fact be quite different , but I have never had the opportunity to do conclusive tests that kept the Cd increase,and then made even more power by adjusting the angle and improving the trapping
and or scavenging ratios.

[Muhr]

Don´t forget speed and the increasing inertia that follows speed.

Sad to see that it went to pieces! On the positive side, you know that you probably have a cylinder pressure over 850 psi for that to happen
Do not know what you mean by that, maybe my english or rather my lack of it that is the problem. You may mean that I was un accurate about when you reach atmospheric pressure and crank compression begins and ends.

[1948rod]

Wobbly or others have you any experience with tuning aimed kf1 engines.

[1948rod]

Sorry spelling came out wrong. Should be Iame kf1 engines

[Makr]

Not at all. Mark used brute force to destroy one of his pistons to the extent that the piston pin was torn out of its holes, but the thread remained impeccable.
I have pictures but I'm not sure I'm at liberty to post them.

Yes you can share them.

I have redesigned the piston anyway with the dome and pin boss as one piece and the skirt that threads on.

[Frits Overmars]

Mark used brute force to destroy one of his pistons to the extent that the piston pin was torn out of its holes, but the thread remained impeccable. I have pictures but I'm not sure I'm at liberty to post them.
Yes you can share them. I have redesigned the piston anyway with the dome and pin boss as one piece and the skirt that threads on.Thanks Mark. Here is that destruction picture I was talking about.
339211

Are you going to combine that 'piston skirt that threads on' with Denver Lawson's inside-out L-ring that should make ring-guiding bridges superfluous?
339212 339213

[peewee]

some of this stuff seems to be way over my head. whats the advantages of screw on piston tops ?

[Michael Moore]

When you torch a piston you whip off the head and get your big screwdriver, remove the holed piston top and screw a fresh one on and you are back in action a short time.

:)

cheers,
Michael

[Flettner]

You guys are so last year, (15 years ago)
Copper screw in top, built for my uniflow engine but never run. Clearly for the exhaust piston. Well finned underneath as to cool it best. These pistons were to run in the exhaust crankcases, fuel (petrol) air was at 6 to 1 ratio. Opposite crankcase were air only, subsequent mixing in the cylinder made the ratio out to approx 12 to one.

[F5 Dave]

some of this stuff seems to be way over my head. whats the advantages of screw on piston tops ?
Look back at old pics, I first saw on my phone and couldn't see the reverse dyke ring ledge. Ring can be limited in bulge and pin holes covered. I don't understand how they can be lighter.

[ken seeber]

Rings.
With the Adegnes’s proposal for a full 180 deg circumference exhaust port and the mutually complimentary 2 piece piston construction (eg Mark and others), it is timely to think about the rings & its matching piston design.
If we consider a series of rings with the same radial depth, there are subtle differences. In all cases, the primary sealing force is activated by the dimension X. Secondary sealing force is the same, given the same radial depth.

1. Rail ring. Simple, allows the top land to contact the bore and dissipate heat, does provide an opportunity to radius the crown edge for say the A & B ports and leave the edge sharp for the C port. It can be argued that it does not provide super sharp timing due to the leakage path due to the radial clearance of the top land to the bore.

2. Conventional Dykes ring. Generally positioned so that its top edge aligns with the curvature of the crown. Has more primary sealing force due to the increase in X, has no top land for heat dissipation, but also “sharper” timing. No opportunity for selectively radiussing the “crown” edge. Seemingly a feature for fixed ratio karts; virtually all Italian engines use Dykes rings. I’m sure they have been thoroughly “back to back” tested many times over the years and they are still being used. The well known exception to this is the Rotax Max, but it is to be noted that this has a plated bore, whereas the Italian motors use a CI liner.

3. Inverted Dykes. Maybe a better name would be a reversed or inside out Dyke. Te reality is that it is really just a rail ring with an inner shoulder to act as a retaining feature. Slightly heavier than a rail ring. Does offer the posssibility to selectively radius the crown edge in various locations and does allow top land contact with the bore. Does require a 2 piece piston to allow it to be installed. Also obvious is the fact that there must be some tight clearance control between the inner shoulder and the piston recess to provide adequate control of the ring expanding to a minimim degree; ie to prevent it expanding outwards and snagging into the super wide exhaust port with the resultant sadness. This requirement also means that any ring wear might prevent the ring contacting the bore, but I guess we are only talking about high performance engines here.

However, it’s all good stuff and gets the brains ticking.

339222

[adegnes]

It just occurred to me, why stop at the exhaust port? I think I'm going to delete a couple of transfer bridges too, have the duct walls end 1mm or so outside the bore. Really hope this ring works.
In a rush to become friends with fusion360 and get this cylinder drawn up.

[OopsClunkThud]

I would think the inverted dykes would have the lip pointed down, otherwise the pressure on both sides of the lip cancel each other.

Also, does this offer the same resistance to flutter? Seems that if it lifts to the top of the slot it no longer has any area in X pushing it out, so same case as a standard ring.

[Flettner]

I miss the 'Ryger days' when it was none stop speculation and truly off the wall stuff here.
Ring design, interesting, keep it going, there has to be a better way.
I still like my ring in the cylinder idea but have zero proof of it's workability. I guess I should just try it. But it does revolve around a guided piston, like the epicyloid bottom end I have made would provide.

[SwePatrick]

I wouldn´t acually trust that new mumbo jumbo ring too much.

As you need some movement on the ring to let it grow in the piston, due to heat(matrialgrowth) and combustionpressure to seal it to the cylinderwall.
If you just restrict the ring in the piston to a certain limit, it probably would loose it´s seal to the cylinder.
And if letting the ring 'float' a little to follow the cylinderwall in different tempratures and pistonmovement(rocking) it can hook into a port.
It just needs a couple of hundreds of a millimeter to fail.

It will sure revolutionize.....
The speed one scraps the cylinders.

[adegnes]

Here's a variation on my "pinned" ring idea.

339223

The ring is located with the hole in the middle of the 100% exhaust port.
The cylinder could be turned 90° to normal orientation and the pin could be pressed(or threaded) into the piston from the underside through a hole in the wrispin boss.
A conventional piston could be used, and as the exhaust side of the wristpin would never encounter any transfer ports, only that side would need to be blocked, maybe even just plugging the pin with something would suffice.

Watcha think? Mumbo jumbo?

I could happily spend the rest of my days failing trying "stupid" stuff.

[teriks]

Here's a variation on my "pinned" ring idea.

339223

The ring is located with the hole in the middle of the 100% exhaust port.
The cylinder could be turned 90° to normal orientation and the pin could be pressed(or threaded) into the piston from the underside through a hole in the wrispin boss.
A conventional piston could be used, and as the exhaust side of the wristpin would never encounter any transfer ports, only that side would need to be blocked, maybe even just plugging the pin with something would suffice.

Watcha think? Mumbo jumbo?

I could happily spend the rest of my days failing trying "stupid" stuff.
Well, I have no input on ring design, but I have ran very wide wide exhausts, and the exhaust port oriented as you suggest.
Even without rings things got difficult around 90-95%. Better start smaller and work your way up.

[wobbly]

The reversed L ring design that was finally patented by Savice Ltd was tested with 100% bore T port ( no T ) and was reliable.
So the concept is workable.
I have suggested to Makr that combining that idea with no external pin bore holes as well,would be a real advance to the SOTA.
Adegnes - dont go overboard , cutting away the transfer septum's will lose all the directional control.
The streams are supposed to be coherent in shape as they exit the duct , having one big hole will create instant short circuiting and a crap scavenging regime ie the Leaning Tower of Frits
will fall over.

[adegnes]

The reversed L ring design that was finally patented by Savice Ltd was tested with 100% bore T port ( no T ) and was reliable.
So the concept is workable.
I have suggested to Makr that combining that idea with no external pin bore holes as well,would be a real advance to the SOTA.
Adegnes - dont go overboard , cutting away the transfer septum's will lose all the directional control.
The streams are supposed to be coherent in shape as they exit the duct , having one big hole will create instant short circuiting and a crap scavenging regime ie the Leaning Tower of Frits
will fall over.

I have a tendency to jump in.
But if my port walls end just shy of the bore in a sharp point to get that tiny last bit of area, shouldn't that retain the same directional control?
The A/B walls "traditionally" converge a bit into the bore, now they converge a tiny bit before it.

[Makr]

Thanks Mark. Here is that destruction picture I was talking about.
339211

Are you going to combine that 'piston skirt that threads on' with Denver Lawson's inside-out L-ring that should make ring-guiding bridges superfluous?
339212 339213



Yes, although I am not going to use an L ring... that is patented. It will still retain the ring.

I am running at ElMirage this weekend, and then after I can tear the bike down and put the engine back on the dyno. Adegnes asked if I could try running no exhaust bridge, so I have some old sleeves I can put back in to see if it works. I have the piston domes machined. Just need to finish the skirts.

[Makr]

Since I am pondering piston rings and placement on the piston I have this thought that I don't think we have talked about.


Or maybe I just have forgotten.


We set port timing by the edge of the piston crown. Yet the ring is roughly 2mm down and is the real seal surface. Is our port timing off? I ask because if I made a regular dykes style ring that seals at the crown tangent point is the timing going to change? Does this matter? Anyone test this?

[adegnes]

I have a tendency to jump in.
But if my port walls end just shy of the bore in a sharp point to get that tiny last bit of area, shouldn't that retain the same directional control?
The A/B walls "traditionally" converge a bit into the bore, now they converge a tiny bit before it.

Are these "dead spots"(green) necessary, or just a product of the need for bridges of a certain thickness for a traditional ring to survive?

339226

My idea would be like re-sleeving a cylinder to a slightly smaller bore, keep the same port angles but let them end in a sharp edge just outside the bore.

[Frits Overmars]

Are these "dead spots"(green) necessary, or just a product of the need for bridges of a certain thickness for a traditional ring to survive?

339226Neither. You do need bridges there, but they need not be wider than about 4° each (see the difference between trailing and leading position angles below right) or about 4% of the bore.
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I would not use a sleeve if I were you, Alex; it would seriously hamper heat transfer.

[_____]

We set port timing by the edge of the piston crown. Yet the ring is roughly 2mm down and is the real seal surface. Is our port timing off? I ask because if I made a regular dykes style ring that seals at the crown tangent point is the timing going to change? Does this matter? Anyone test this?

I once checked that with an 1D/0D simulation programm, by adding a very small "nose" upon the exhaustport.
The nose is increasing the exhaustport height with the height of the ringland, the width is the circle-ring area of the ringland. The difference was quasi non existent, since the cross-section of this "port" is way to small for serious mass flow.
Comparable to a foulstroke where the valve opening perioud is only interesting after 1.0mm of valve lift.

On the "reversed" Dykes ring: The ring land on a few pistons of mine looked pissed as well, whilst dealing with a big exhaust port.
@wob, which dimension of pistons were tested with the 100% exhaust-width? D54mm? How long used?

Cheers, Chris

[adegnes]

Neither. You do need bridges there, but they need not be wider than about 4° each (see the difference between trailing and leading position angles below right) or about 4% of the bore.
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I would not use a sleeve if I were you, Alex; it would seriously hamper heat transfer.

Yes, that drawing was of the original iame M50 cylinder, lot's of dead space.

But if the ring didn't care, wouldn't 0° be even better?

339236

Worry not, people have offered to coat the cylinders for me, no liner.

I really want to do everything but the coating "in house", a long way there both equipment- and knowledge wise.

[SwePatrick]

Due to piston is tapered it can rock in the bore.
This makes it very hard for the ring to seal if you restricts it´s movement.
And piston is rocking the most in bdc and often is the ring hooking into the exhausts 'floor'

There are no free lunch here, sadly enough.

[Frits Overmars]

... if the ring didn't care, wouldn't 0° be even better?

339236Even if the ring doesn't care (I have my doubts), the piston will; it will act according to Murphy's Law: if it can topple into a port, it will. You'd need quite a long piston. Or instead of combining Mark Atkinson's piston with Denver Lawson's inside-out L-ring, you could go the whole way and copy Flettner's epicyclic crank-rod system. That has a much better guidance plus a handful of other advantages.

[adegnes]

Due to piston is tapered it can rock in the bore.
This makes it very hard for the ring to seal if you restricts it´s movement.
And piston is rocking the most in bdc and often is the ring hooking into the exhausts 'floor'

There are no free lunch here, sadly enough.


Even if the ring doesn't care (I have my doubts), the piston will; it will act according to Murphy's Law: if it can topple into a port, it will. You'd need quite a long piston. Or instead of combining Mark Atkinson's piston with Denver Lawson's inside-out L-ring, you could go the whole way and copy Flettner's epicyclic crank-rod system. That has a much better guidance plus a handful of other advantages.

But I want my free lunch!
If I only delete the B/C bridges, and run the cylinder 90° twisted to have most of the thrust load where there's actually some wall left?
I'll go back and read up on Fletners crank(and the ring in bore idea)

[Muhr]

Since I am pondering piston rings and placement on the piston I have this thought that I don't think we have talked about.


Or maybe I just have forgotten.


We set port timing by the edge of the piston crown. Yet the ring is roughly 2mm down and is the real seal surface. Is our port timing off? I ask because if I made a regular dykes style ring that seals at the crown tangent point is the timing going to change? Does this matter? Anyone test this?

I put 170psi on a 4mm2 and 2mm high cube which of course is very much better boundary layer condition.
around 600ms so about 0.123cc at 13000 rpm on a 125cc but probably much much lower

[SwePatrick]

But I want my free lunch!
If I only delete the B/C bridges, and run the cylinder 90° twisted to have most of the thrust load where there's actually some wall left?
I'll go back and read up on Fletners crank(and the ring in bore idea)

You need the bridges to control the direction of the incoming gasses, if you blend them together before entering the bore you need to start develop the shape again to get the correct direction for effictivly scavenge the bore.
I can be brave and say it´s equally important in the exhaust also.

Don´t underestimate existing solutions, they have been developed for many many years to have reached the shape they´ve got today.

[wobbly]

There is no dead area in front of the boost port.The hook ( radius ) twists the inflowing gas column axially underneath the boost port.
Its real easy to see for yourself, turn a cylinder upside down that has the B port hook , and use a stream of water dropping down into the duct from a tap.
You will see immediately the effect , hard to explain , harder to understand how it happens.
Many of the latest high performance cylinders have the rear wall of the B port closest to the boost port, crossing the centerline about 1/3 length away from the bore to the mid point.
So this is a much steeper exit angle than around 1/2 way to the bore center as was used previously.

I believe SwePatrick is correct - as I said before the gas columns entering the cylinder must remain coherent - all the way up to the point they become the single leaning tower scavenging loop..
This coherent column flow is even badly affected by the smallest chamfer on the transfer ports at the bore , creating eddies around the columns sides that then detach and become mixed with exhaust residuals.
So if a tiny chamfer fucks the scavenging efficiency imagine what will happen to two individual flow streams colliding " outside " the bore.

[adegnes]

You need the bridges to control the direction of the incoming gasses, if you blend them together before entering the bore you need to start develop the shape again to get the correct direction for effictivly scavenge the bore.
I can be brave and say it´s equally important in the exhaust also.

Don´t underestimate existing solutions, they have been developed for many many years to have reached the shape they´ve got today.

I totally get that point, I don't want to blend them before the bore though.
Look at it this way, I'm not going to remove the bridges, but make them 0.01mm wide. Same angles as before, just that tiny bit more area.

You're of course right about existing solutions, but it's not where the fun is for me.

[TZ350]

.
Been getting my engine back together again after replacing the rod kit and using a special crank pin Flettner made for me that has direct posi lube oiling to the big end.

The current problem I am having is trying to get three variables to align up. Squish, Compression Ratio and Port Timing.

Getting everything correct by hand is so fiddly and time consuming I admit frustration and a less than satisfying result. Next time I am going to pay someone with a CNC machine to make the inserts for me.

339237 339238 339239

[adegnes]

There is no dead area in front of the boost port.The hook ( radius ) twists the inflowing gas column axially underneath the boost port.
Its real easy to see for yourself, turn a cylinder upside down that has the B port hook , and use a stream of water dropping down into the duct from a tap.
You will see immediately the effect , hard to explain , harder to understand how it happens.
Many of the latest high performance cylinders have the rear wall of the B port closest to the boost port, crossing the centerline about 1/3 length away from the bore to the mid point.
So this is a much steeper exit angle than around 1/2 way to the bore center as was used previously.

I believe SwePatrick is correct - as I said before the gas columns entering the cylinder must remain coherent - all the way up to the point they become the single leaning tower scavenging loop..
This coherent column flow is even badly affected by the smallest chamfer on the transfer ports at the bore , creating eddies around the columns sides that then detach and become mixed with exhaust residuals.
So if a tiny chamfer fucks the scavenging efficiency imagine what will happen to two individual flow streams colliding " outside " the bore.

Thank you both for the input!
Interesting about the steeper angles, so in effect they have less "hook"?
Dead space was the wrong word, what I ment was "potential port area not in use". Do you think it's important the columns collide a certain distance from the bore, could sacrificing port area for collision closer to center be beneficial?
If not maybe my razor sharp walls could work?

[jonny quest]

Adegnes, what is the most effective thing on making power in a 2 stroke cylinder? (I said cylinder, don't come at me with pipe)

Focus on that. You can then always grind your transfers one step at a time during testing to verify that getting rid of transfer bridges will lose HP. I'd be more inclined to believe taller transfers may make more power with a superior exhaust port.

[adegnes]

Adegnes, what is the most effective thing on making power in a 2 stroke cylinder? (I said cylinder, don't come at me with pipe)

Focus on that. You can then always grind your transfers one step at a time during testing to verify that getting rid of transfer bridges will lose HP. I'd be more inclined to believe taller transfers may make more power with a superior exhaust port.

Nitromethane/hydrazine mix? 😁

Yeah, sounds like a plan.
If only someone could hand me a bag of money, I could take a year off, buy the necessary equipment, and start chewing through cylinders with ridiculous ideas.

[F5 Dave]

Ahh, you'd spend it all on medicinal grain based beverages.

[41juergen]

I have a problem setting up the carb for a road going bike (TZR125 equipped with a Mikuni TM28 carb). I got the exhaust temp (and lambda) pretty much spot on when the engine is on the pipe. But when beeing at low a revs (e.g. between 4000 and 6000 rpm) the power is weak and the engine feels running very lean (also seen by the lambda trace, and I know the concerns of taking the lambda signal to verfiy how the fueling might be!). So the question is: how can I get the fueling much richer at WOT and below pipe action without messing up the setup at higher revs?

[husaberg]

I have a problem setting up the carb for a road going bike (TZR125 equipped with a Mikuni TM28 carb). I got the exhaust temp (and lambda) pretty much spot on when the engine is on the pipe. But when beeing at low a revs (e.g. between 4000 and 6000 rpm) the power is weak and the engine feels running very lean (also seen by the lambda trace, and I know the concerns of taking the lambda signal to verfiy how the fueling might be!). So the question is: how can I get the fueling much richer at WOT and below pipe action without messing up the setup at higher revs?

If its the same carb as the TMSS on the TZR250 they have a series of air correctors the f3 kit blocks these
The 250 TZR also has a PJ


https://www.kiwibiker.co.nz/forums/showthread.php/142498-MB100-development?p=1130168775#post1130168775
https://www.kiwibiker.co.nz/forums/showthread.php/142498-MB100-development?p=1130169246#post1130169246
https://www.kiwibiker.co.nz/forums/showthread.php/142498-MB100-development?p=1130169333#post1130169333

[41juergen]

If its the same carb as the TMSS on the TZR250 they have a series of air correctors the f3 kit blocks these
The 250 TZR also has a PJ

They are pretty much the same, also with a#50 PJ. It has the air correction screw (which is related to the idle sytem, mainly for low throttle, right?) and the main air jet (which is a #0.6 giving a close to constant lambda during the entire rev range beeing on the pipe). I have played a bit with a #0.5 MAJ with changes in lambda when the engine is on the pipe but not significantly below 6000 rpm...

[husaberg]

They are pretty much the same, also with a#50 PJ. It has the air correction screw (which is related to the idle sytem, mainly for low throttle, right?) and the main air jet (which is a #0.6 giving a close to constant lambda during the entire rev range beeing on the pipe). I have played a bit with a #0.5 MAJ with changes in lambda when the engine is on the pipe but not significantly below 6000 rpm...
out of those links
339245339246
The air jet is used to vary the fuel curve.
With your carb at those revs you have about 4 circuits in play its just a case of juggling the overlaps to get the curve you desire.
if you read up the stuff in the second paragraph you should have a idea which bits to juggle
Unfortunatley its not just a case of saying richen the needle and it will sort it. although it may.
THe TZR250 race kit has a Larger needle jet and different tapper.
https://www.kiwibiker.co.nz/forums/album.php?albumid=4844&page=5

[41juergen]

out of those links
339245339246
The air jet is used to vary the fuel curve.
With your carb at those revs you have about 4 circuits in play its just a case of juggling the overlaps to get the curve you desire.
if you read up the stuff in the second paragraph you should have a idea which bits to juggle
Unfortunatley its not just a case of saying richen the needle and it will sort it. although it may.
THe TZR250 race kit has a Larger needle jet and different tapper.
https://www.kiwibiker.co.nz/forums/album.php?albumid=4844&page=5

Yeah, I have played with the MAJ, but I saw mainly changes only when the engine is on the pipe.... Also at part throttle (let's say between 20-70%) and low revs the engine runs fine. When going to WOT at low rev's and then going backt to approx. 60% the engine revs up quite ok, only at WOT it don't get's enough fuel...

[husaberg]

Yeah, I have played with the MAJ, but I saw mainly changes only when the engine is on the pipe.... Also at part throttle (let's say between 20-70%) and low revs the engine runs fine. When going to WOT at low rev's and then going backt to approx. 60% the engine revs up quite ok, only at WOT it don't get's enough fuel...
It sounds to me that your cutaway and your needle Shroud need optimizing.
with the air Jet the main effect is at the top end of the curve.
the problem is to fix one part of the curve you will need to rejig the other settings as they overlap.
339247339248
When taper an the positioning of the starts and thicknesses of ech taper on the needle will also effect this area.
Yamaha did likely a fair bit of work with the f3 race kit i would suggest the had good reasons for it.
if you are running the same carb on the same size engine it might pay to assume they knew what they were doing and there from there.

[Frits Overmars]

..I got the exhaust temp (and lambda) pretty much spot on when the engine is on the pipe. But.. at low revs.. the power is weak and the engine feels running very lean..
I know the concerns of taking the lambda signal to verify how the fueling might be.. how can I get the fueling much richer at WOT and below pipe action.. So you are aware that a Lambda sensor cannot tell you at all if a mixture is rich or lean. It can only tell you whether there is oxygen present in the exhaust gases.
Scavenging losses at low revs as a result of washed-through mixture will make sure of this oxygen presence. And misfiring because of an overly-rich mixture can enhance this presence even more, so enrichening the mixture at low revs may well worsen the 'lean' situation.
There are three things you can do about it. The first is copying Flettners cylinder with variable transfer timing. The second, somewhat simpler option, is to shift down when the engine threatens to drop out of its power band. The third option is to get an engine without a power band (and without two-stroke power),
a so-called foulstroke or Falschtakter :msn-wink:.


.. at part throttle (let's say between 20-70%) and low revs the engine runs fine. When going to WOT at low revs and then going back to approx. 60% the engine revs up quite ok, only at WOT it don't get enough fuel...You won't expect to get much power at part throttle, so whatever you do get, can be fine. At WOT you'll have higher expectations; you will also have a higher crankcase pressure and bigger scavenging losses. To some extent those losses can even be helpful in lowering the exhaust gas temperature to a level that is more suitable for those low revs.
Have you tried varying the ignition timing? Giving more advance should improve low-down power, but can become dangerous around maximum torque rpm.
A programmable ignition could be the best of both worlds, short of using that variable-height Flettner-cylinder or building a trombone exhaust pipe.

[41juergen]

It sounds to me that your cutaway and your needle Shroud need optimizing.
with the air Jet the main effect is at the top end of the curve.
the problem is to fix one part of the curve you will need to rejig the other settings as they overlap.
339247339248
When taper an the positioning of the starts and thicknesses of ech taper on the needle will also effect this area.
Yamaha did likely a fair bit of work with the f3 race kit i would suggest the had good reasons for it.
if you are running the same carb on the same size engine it might pay to assume they knew what they were doing and there from there.



So you are aware that a Lambda sensor cannot tell you at all if a mixture is rich or lean. It can only tell you whether there is oxygen present in the exhaust gases.
Scavenging losses at low revs as a result of washed-through mixture will make sure of this oxygen presence. And misfiring because of an overly-rich mixture can enhance this presence even more, so enrichening the mixture at low revs may well worsen the 'lean' situation.
There are three things you can do about it. The first is copying Flettners cylinder with variable transfer timing. The second, somewhat simpler option, is to shift down when the engine threatens to fall out of its power band. The third option is to get an engine without a power band (and without two-stroke power),
a so-called foul-stroke or Falschtakter :msn-wink:.

You won't expect to get much power at part throttle, so whatever you do get, can be fine. At WOT you'll have higher expectations; you will also have a higher crankcase pressure and bigger scavenging losses. To some extent those losses can even be helpful in lowering the exhaust gas temperature to a level that is more suitable for those low revs.
Have you tried varying the ignition timing? Giving more advance should improve low-down power, but can become dangerous around maximum torque rpm.
A programmable ignition could be the best of both worlds, short of using that variable-height Flettner-cylinder or building a trombone exhaust pipe.

@ Husa: May be I need to mention that I have changed the setup in the following way: the carb is equipped with a MAJ which has a connection to the outside atmosphere (and has some variable AJ's as beeing from my 3XV, may be similar as the RGV's have). I wanted to get rid of that and blocked the hose connector and installed a "fixed" MAJ #0.6 in the designed channel at the inlet bellmouth of the carb. With that I have changed the general setup at the needle jet significantly. I got back the ex temp within the power band by adjusting the MJ, all good there. What I did not have tried is a MAJ much bigger, e.g. #1,5 or so as I saw only a mall change when going up and down of an 0,1 increment for the MAJ. So the main question is if the MAJ also has a significnat influence on the fuelling when beeing below the power band.

@Frits: as said, I have learned from you guys what the bondaries of using a lambda sensor are... :yes: The engine is still not a seriuos tuned 2 stroker, it has the top end and intake from my 3XV which is a 28 hp 125 ccm setup. As mentioned, it is a road going bike with air filter, so shall run kind of reasonably propperly also below the power band... All the other stuff will come later during the winter time, I try to learn as much as possible (I know that will be limited) from that basic setup before going into serious power, but without Flettners idea :shifty:
The bike has already a programable ignition, it has about 28°CA below the power band and it had better power below the power band when using the stock 3XV carb setup with the VAJ connected. So my prom is to get back the performance without using the VAJ's... A typical case of down tuning at the moment!:facepalm:

[adegnes]

Ahh, you'd spend it all on medicinal grain based beverages.

You know me too well...

[Flettner]

So, if we are going to run the exhaust out to 100 % of the bore width then are we looking at perhaps two exhaust ports? To get the best out flow.

[adegnes]

So, if we are going to run the exhaust out to 100 % of the bore width then are we looking at perhaps two exhaust ports? To get the best out flow.

Two ducts/pipes, one port, or two ports/ducts/pipes?
Might struggle with short circuiting even without going past 180°?

[ken seeber]

So, if we are going to run the exhaust out to 100 % of the bore width then are we looking at perhaps two exhaust ports? To get the best out flow.

Fletto, you know the answer. Don't fuck around with 2 exhausts when you can have three:

339250

339251

Just gotta get some wanker to finish it off..:niceone:

[adegnes]

Fletto, you know the answer. Don't fuck around with 2 exhausts when you can have three:

339250

339251

Just gotta get some wanker to finish it off..:niceone:

I need to catch up up in the foundry thread.
How's it running?

[jasonu]

You guys are so last year, (15 years ago)
Copper screw in top, built for my uniflow engine but never run. Clearly for the exhaust piston. Well finned underneath as to cool it best. These pistons were to run in the exhaust crankcases, fuel (petrol) air was at 6 to 1 ratio. Opposite crankcase were air only, subsequent mixing in the cylinder made the ratio out to approx 12 to one.

Best patent that before some prick nicks the idea...

[SwePatrick]

As i had a lot of problems with foaming fuel i´m trying a new approach, dunno if it´s working yet.
I had the carb(another one, a vm44, very heavy) mounted in a silicone hose, and it vibrated very freely and also had some harmonics that added a lot of movement.
So i figured, the engine doesn´t move as much as the carb did.
So my new approach is to mount the carb more rigid, so less movement is allowed, still vibrations will ofcourse be transfered,
But i guess the 'sinuscurve' of the movement will be less.

There are also a 'stuffer' protruding into the reedcage.

339268339270

Stuffer not 100% complete yet.

[wobbly]

Really interested to hear what jet mods were done to get the downdraft carb to work on the 2T.
I got close by replicating the needle/tube areas from a PWM , but never overcome the wierd issue that only one ( rich ) slide cutaway is available for normal 4T use ( along with a accelerator pump ).

[Tim Ey]

[...]
https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=251584&d=1322335047
the third a rendering of the tiny alternator, using NdFeB magnet material out of a F&P Smartdrive.

Hi Wob,
do you recall what size the outer Diameter of the rotor was and how much electrical power was to gain with it?
Thanks!
Tim

[wobbly]

The OD of the rotor was a 40mm stainless ring.
On the bench it would produce 6A using a clamp gauge, dead shorted at 12,000 rpm.
The open circuit voltage was 80V at 12,000.
Used the reg/rec off a late model TZ250 Yamaha.

[SwePatrick]

Really interested to hear what jet mods were done to get the downdraft carb to work on the 2T.
I got close by replicating the needle/tube areas from a PWM , but never overcome the wierd issue that only one ( rich ) slide cutaway is available for normal 4T use ( along with a accelerator pump ).

I have modified the throttle a lot to beeing able to tune the cutaway.
The 'venturi ring' in the carb is gone, and i have replaced it with two slides that protrude into the slidebore, and then i have made a 'small' normal throttle inside the hollow throttle, just to look more alike a lectron, but with two 'throttleblades' instead of one in a lectron(that exposes the needle to vaccum)
Then the 'vaccumplate' on the throttle is mounted solid.
Acceleratorpump is deleted.
The tube and needle is as you did, copied from a PWM.

And finally, it´s supposed to run on methanol in dragraing, perfect carburation on low loads isn´t very important ;)

[Tim Ey]

The OD of the rotor was a 40mm stainless ring.
On the bench it would produce 6A using a clamp gauge, dead shorted at 12,000 rpm.
The open circuit voltage was 80V at 12,000.
Used the reg/rec off a late model TZ250 Yamaha.

Whow. Thats more juice than i hoped for.
Did you put them all in a line or "classical" as a Y-connection?

Thanks to Ebay you can buy neodym magnets in any shape rightaway.
And thanks for 3D printing and lasercutting I can easily built the stator to suit.

Thanks wob!

[wobbly]

The coils were all in series , and we changed wire diameter and turns numbers to get what I thought was needed.
Our ECU pulled around 4A @ 14.2V so going for 6A seemed about right, tho clever buggers told me the actual " power " of the unit depended
upon the current and voltage under load - never measured it as it worked straight up.
The whole stator was vacuum impregnated with Araldite , as that process was used at Buckleys to make magnet assemblies for medical scanners and the ion beam lines for chip manufacture.
The stator plates were laser cut from a special grain orientated steel, and the NdFeB magnets wire cut from an F & P SmartDrive assembly - they magnetized them after cutting.

[karter444]

Hi Wobbly
someone has posted on FB photos of what is supposedly the next homolagated kz engine from TM called the
KZ R1 . Is this the engine that you have had some input into regarding its design and if so , now that it will be available for sale in december are you able to detail some of the differences between this engine and the current model
In regard to the B/C engines do you prefer to use the cylindrical roller main bearing or to change to a micro blue ball bearing race and are you allowed to machine the outer dia of a crank half

Cheers Richard

[husaberg]

I seen a blurb about one of the homol 125's karts now having a very much shorter rod now.
Modena i haven't read it yet.
https://www.tkart.it/en/toolbox/kart-connecting-rod-length-compared2/

[wobbly]

If you look at the homologation papers the crank OD is detailed, so you cant change it , but with the C model bigger pin I wouldnt do it anyway.

The R1 engine design is what i was working on , not allowed to say what is different - except the pipe of course as many would know already.
Much of the really good stuff is being kept for the factory versions , so you wont see any of that for quite some time.
But you can obviously see that the gear shafts have been rotated , down at the back.

[adegnes]

I seen a blurb about one of the homol 125's karts now having a very much shorter rod now.
Modena i haven't read it yet.
https://www.tkart.it/en/toolbox/kart-connecting-rod-length-compared2/

Looking forward to hear back from you when you've read it!
Wonder what the fluid dynamics and resonance advantages are with the shorter rod? Shorter transfer ducts?

Btw, I'm picking up an old Kiln this weekend, and a 3D printer should arrive monday. Plan is to cast cylinders with lost PLA. Won't be too long until I can start testing my more or less stupid ideas! Really fighting with fusion360 though, found a way to get the transfers right pretty effectively with a combination of revolve and extrude, but the exhaust port/duct is difficult. If only it was possible to loft from a curved plane/face.

[wobbly]

You only have to look at the latest results in Europe to see what engines got the rod right.
TM ( still on top ) kept the 109.8 length ( a mistake made many years ago , it should have been 110 ), Vortex in the last few events have made a big comeback with the 115 rod.
Modena - nowhere.
But Vortex have already had their new homologation , the TM R1 new version wont be seen till next year.

I tried the rollers in the B, but due to the 20mm pin flex it shat the main bearings several times.
In the C the bigger pin causes less roller wear, but you MUST have a dead straight crank ( under 0.002mm both sides ) or the crank oscillates back and forth within the end play , then the bearing lock up.
Yes I prefer the Micro Blue ball , never had one die , and a tiny ( but repeatable )increase in measured power - all for way less cost.
The only technical upside to the rollers is they have double the theoretical dynamic load capability,but in practice the increase in rolling friction and the huge sensitivity to end loading just isnt worth it as they for
sure dont last twice as long.

[OopsClunkThud]

If only it was possible to loft from a curved plane/face.

Use patch mode to create a surface off your port solid or parts of it. then use thicken off the surface to create the wall solid.

[adegnes]

Use patch mode to create a surface off your port solid or parts of it. then use thicken off the surface to create the wall solid.

Thanks, I'll play with it tonight.

[dutchpower]

Why Homologation Wobb

If much of the really good stuff is being kept for the factory versions

[husaberg]

Looking forward to hear back from you when you've read it!
Wonder what the fluid dynamics and resonance advantages are with the shorter rod? Shorter transfer ducts?

Btw, I'm picking up an old Kiln this weekend, and a 3D printer should arrive monday. Plan is to cast cylinders with lost PLA. Won't be too long until I can start testing my more or less stupid ideas! Really fighting with fusion360 though, found a way to get the transfers right pretty effectively with a combination of revolve and extrude, but the exhaust port/duct is difficult. If only it was possible to loft from a curved plane/face.
I read it straight after I can't say that they have explained anything about the Whys?
AS Wob alluded rhe proof is in the pudding and their results suggest no ones getting drunk on champagne with the short rod.

[SwePatrick]

I´m struggeling with bad traction on dynoroller now, I will change the rear wheel tomorrow to the same I had 2017, that never slipped.

If you follow the blue line at top on dynochart.
It is calculated gearratio, it should be the same through the whole rpm range.
Where white arrow is, is where the new slipperclutch engages.
It doesn´t show, but when the bike should have ~170km/h on the roller, it only has 121km/h, that is a lot of power being spun away.
And today, the pic doesn´t show, the rear tire became flat after 4 pulls.
And already at third pull the bike were loose in the rear, it kind of 'drifted' like drifting on the roller.

Result is 49.95hp 11750rpm with a lot of tractionproblems.
The peakpower should be around 12600-13000rpm ;)


339283339284

[karter444]

You only have to look at the latest results in Europe to see what engines got the rod right.
TM ( still on top ) kept the 109.8 length ( a mistake made many years ago , it should have been 110 ), Vortex in the last few events have made a big comeback with the 115 rod.
Modena - nowhere.
But Vortex have already had their new homologation , the TM R1 new version wont be seen till next year.

I tried the rollers in the B, but due to the 20mm pin flex it shat the main bearings several times.
In the C the bigger pin causes less roller wear, but you MUST have a dead straight crank ( under 0.002mm both sides ) or the crank oscillates back and forth within the end play , then the bearing lock up.
Yes I prefer the Micro Blue ball , never had one die , and a tiny ( but repeatable )increase in measured power - all for way less cost.
The only technical upside to the rollers is they have double the theoretical dynamic load capability,but in practice the increase in rolling friction and the huge sensitivity to end loading just isnt worth it as they for
sure dont last twice as long.

thanks for the reply
cheers Richard

[Michael Moore]

found a way to get the transfers right pretty effectively with a combination of revolve and extrude, but the exhaust port/duct is difficult. If only it was possible to loft from a curved plane/face.

You might try doing your loft from points before to points after the duct, and then trim the excess off as needed.

cheers,
Michael

[wobbly]

What is the issue with getting the Ex port/duct modeled.
You have the Ex port shape you want ( a sketch on a plane across the bore offset from the mid line plane ), and you know the duct exit shape ( on an angled plane offset from the same mid line plane ).
Then all you need are multiple guide curves between the two to generate the duct shape along its length.
You can then also use the end point guides to make it any angle you want where the cut/loft enters the bore and then exits the casting.
The guide curve splines enable you to achieve the droop in the roof ( between the bore and the side Aux duct entry (, as well as the floor ski jump .Both of which reduce the duct volume in the right places.
Doing the duct as a surface extrude and then thickening it outward is one good way of generating a consistent water cooling jacket as well.
But many people do the reverse and generate a port core solid ( that can then also be used to manufacture the casting core easily ).

[wobbly]

Dutch , the homologation of the new engine still allows huge changes in the head and port/duct configurations.
I wont know till I talk to Franco at Vegas exactly how much of my input will be seen in the first customer R1 engines.
Its all very secret squirrel and hugely ego driven - but im not after any sort of recognition ,as I got paid anyway ,and can still implement the tested ( but maybe unused ) details in new engines I build.

[adegnes]

What is the issue with getting the Ex port/duct modeled.
You have the Ex port shape you want ( a sketch on a plane across the bore offset from the mid line plane ), and you know the duct exit shape ( on an angled plane offset from the same mid line plane ).
Then all you need are multiple guide curves between the two to generate the duct shape along its length.
You can then also use the end point guides to make it any angle you want where the cut/loft enters the bore and then exits the casting.
The guide curve splines enable you to achieve the droop in the roof ( between the bore and the side Aux duct entry (, as well as the floor ski jump .Both of which reduce the duct volume in the right places.
Doing the duct as a surface extrude and then thickening it outward is one good way of generating a consistent water cooling jacket as well.
But many people do the reverse and generate a port core solid ( that can then also be used to manufacture the casting core easily ).

Thanks for the tips!
The issue is that this is my first cad project ever, jumped in at the deep end...
I'll get there!

[Muhr]

Thanks for the tips!
The issue is that this is my first cad project ever, jumped in at the deep end...
I'll get there!

https://vimeo.com/297544690

This is one way

[adegnes]

https://vimeo.com/297544690

This is one way

Thanks! That's kinda how I try to do it though with multiple sketches, planes, and rails like wobbly describes.
Starting to get a hang of it, will keep on trucking tonight.

[Muhr]

Thanks! That's kinda how I try to do it though with multiple sketches, planes, and rails like wobbly describes.
Starting to get a hang of it, will keep on trucking tonight.

The more sketches you make the greater the tendency, it starts bugging if you want to make changes to your finished model. sometimes less is more.

Lucka till:D

https://vimeo.com/297600399

[TZ350]

.
Edgecombe

Tim from Team ESE took out this seasons AMMC F5 Bucket Championship.

339288 going down hill with the wind up its arse.

And Tim also gave the water cooled Suzuki NSR-GP 110 its maiden outing in A grade F4.

Easy to get the main jet right on the dyno but it took the best part of the day to get the needle, slide cutaway and pilot jet right. By the end of the day it was fair buzzing around the track.

This build was all about using basic parts without any tricky porting or pipe building. Stock cases, standard inlet and original GP carburetor, original NSR cylinder, re plated but no porting work at all and a discarded pipe from an old NF4 RS125. The only trick part is the de stroked crank. If you can get the crank done then the rest of it is basic engineering with no clever 2 stroke tuning knowledge required at all to have a competitive F4 bike.


338617 338618 338619

Ok... now we know. The basic GP-NSR110 build is 25rwhp. Basic because we wanted to make something that you did not need to be a 2T tuning expert to re produce.

No porting, no trick parts, just a basic Suzuki GP100 bottom end with a de stroked crank, cut rotary valve 145/85 and fitted with a stock NSR250 cylinder and crappy NSR head and still running the stock Suzuki GP 24mm carburetor.


Follow the link to read the whole story about Team ESE's GP/NSR110cc engine build. You will have to follow the links to see the whole post, pictures and related links.

[jasonu]

.
Edgecombe

Tim from Team ESE took out this seasons AMMC F5 Bucket Championship.

339288 going down hill with the wind up its arse.

And Tim also gave the water cooled Suzuki NSR-GP 110 its maiden outing in A grade F4.

Easy to get the main jet right on the dyno but it took the best part of the day to get the needle, slide cutaway and pilot jet right. By the end of the day it was fair buzzing around the track.

This build was all about using basic parts without any tricky porting or pipe building. Stock cases, standard inlet and original GP carburetor, original NSR cylinder, re plated but no porting work at all and a discarded pipe from an old NF4 RS125. The only trick part is the de stroked crank. If you can get the crank done then the rest of it is basic engineering with no clever 2 stroke tuning knowledge required at all to have a competitive F4 bike.

hey Rob where are you racing now Mt Welli is done? That must be a big hit to the program.

[TZ350]

.
Yep Mt Welly is gone. There are quite a few cart tracks around in other towns. I think the current plan is to do a two day camping on site away meeting maybe every two months.

[adegnes]

The more sketches you make the greater the tendency, it starts bugging if you want to make changes to your finished model. sometimes less is more.

Lucka till:D

https://vimeo.com/297600399

Thanks!
Very true.
My first attempts were like in your videos, the problem is the first section with 0° exit angle. I'm trying to find the least complicated way to have a 20° exit angle from the bore wall while retaining the right port shape. Harder than I thought it would be.

[Muhr]

Thanks!
Very true.
My first attempts were like in your videos, the problem is the first section with 0° exit angle. I'm trying to find the least complicated way to have a 20° exit angle from the bore wall while retaining the right port shape. Harder than I thought it would be.

Then I would probably do as before but in sculpt environment and adjusting it whoever wishes

[adegnes]

Then I would probably do as before but in sculpt environment and adjusting it whoever wishes

Good idea, thanks!
Haven't used sculpt at all yet.

[Muhr]

I wonder if somebody has tampered with TPS and 3d ignition curve and if so you notice any major improvement in throttle respons after a long throttle let off.
If it's worth the trouble.

[wobbly]

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

[Muhr]

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

Thank Wobbly
The thought was that it would be used for an engine with quick shift and electronic power jet. There is more an on/off throttle application with fairly long throttle let off.
So the idea was that you could clean up a little in the barrel if needed.

[wax]

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

We run up to 34 degrees on the jetskis

[_____]

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

Also you avoid having a "racing idlespeed". This occures while having ~30° with a single map. The engine does not fall lower than that whilst beeing hot.

[SwePatrick]

The 3D map allows you to take timing out when pulling low/med rpm with little throttle opening.
This is where the engine will deto if running up around 28* in a single curve map.
But 28* is what you want when at low/mid rpm under the pipe , when at full or near full throttle.
This gives way better throttle response.

Isn´t 28* a bold statement as every engine is unique?
Or was it just an example?

A rule of thumb in foulstroke engines is the less time to burn the more advance needed, and the less 'filled cylinder' the more advance needed.
And ofcourse vice versa on both.

This two combined creates a curve both with boosted engines as unboosted.

Wouldn´t it be the same in twostrokes?
but with one change, the more pipe the less ignition needed(like a ignitionretard on boosted foulstroke engines)

[wobbly]

The 28* was just an example, but is very advanced for any engine with a single curve map when there is the possibility of any time spent at part throttle with that timing..
Jetski engines do run well over this to get the snap throttle response, but are never run in that zone for any length of time at part throttle , and the fast acceleration rate ensures no damage occurs.
Rob had this very issue on one of the ESE bikes , where the best power advance on the dyno would deto like hell on the track in the mid range , when it wasnt accelerating quickly at full throttle.
A 3D map makes fixing this issue easy.
A 2T essentially needs an ignition " curve " the inverse of the bmep , thus as the pipe efficiency increases ( along with the PV opening if used ) the dynamic compression increases dramatically and as
has been mentioned many times , when everything is in sync at peak , then we tend to end up with 15* advance.

[Muhr]

Another thing I think might be worth mentioning as below.
very rough numbers but.

10,000 rpm and exhaust port opening time of 0.003s and 780mm pipe = 400 c °
11,000 rpm and exhaust port opening time of 0.0027s and 780mm pipe = 565 c °
12,000 rpm and exhaust port opening time of 0.0025s and 780mm pipe = 700 c °

[Muhr]

Good idea, thanks!
Haven't used sculpt at all yet.

Another way to do that, progressive radius on top.

[adegnes]

Another way to do that, progressive radius on top.

Funny - exactly what I just started playing with!

[Muhr]

Funny - exactly what I just started playing with!

You could of course project from a negative at the desired angel
works perfect! Sometimes I'm a bit stupid

[adegnes]

You could of course project from a negative at the desired angle

Clever! Thanks!

[TZ350]

Rob had this very issue on one of the ESE bikes , where the best power advance on the dyno would deto like hell on the track in the mid range , when it wasn't accelerating quickly at full throttle. A 3D map makes fixing this issue easy.

Sure did, great torque curve on the dyno. At Kaitoki Kel blasted it around the track great guns in practice and for qualifying. I was pretty sure we were going to kick arse but the engine died from detonation just trickling around the track during warm up for the main race. Had a similar problem at Taupo a couple of weeks earlier. A TPS and 3D ignition map sorted it.

[jbiplane]

I finally setup and start production of 5-axis milled cylinders.
Heads and "spiral" resonators should be ready soon.http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=75547&d=1541061205
http://www.homebuiltairplanes.com/forums/attachment.php?attachmentid=75548&d=1541061256

[TZ350]

339315

That cylinder is very impressive work..... :niceone:

[TZ350]

339317

Fuel dropout in the plenum is what inspired me to go fuel injected.

339318

Engine back together after getting a new rod kit and direct B/E oiling modification. Setting the squish accurately to 0.65mm by hand and compression ratio to 14:1 took a bit of time.

339319

24 - 1 tooth trigger wheel ring made from an Aprilia SR50 flywheel and pressed onto the original GP-NSR110 flywheel.

[Tim Ey]

24 - 1 tooth trigger wheel ring made from an Aprilia SR50 flywheel and pressed onto the original GP-NSR110 flywheel.

Oh, thats damn clever! What is the original inner and outer diameter of the SR50 Flywheel?
Regards
Tim

[Muhr]

Thanks for the heads up about the inner transfer duct radius.


With the Power Valve set to open at 96deg ATDC there are significant gaps around the PV blades.

The PV's are fiddly and difficult to get in and out so I cut a damaged cylinder to make a jig to make it easier for welding and grinding them to a closer fit.

TZ350
Were in the garage yesterday and sanded on a PV similar to the one you have, then come and think of that you discussed it a while ago. The one I did was also cast, we preheated them to about 300 ° C and then TIG welded with 316. Also had a 3d model on nsr j20 do not know how similar it is but. Probably you've already solved it.

[F5 Dave]

Sunday night music interlude.
She really is wonderful.

https://m.youtube.com/watch?v=0df0racc3vk

[SwePatrick]

Today i paid my debt´s to the gods of speed ;)

I almost reached my goal,, so very close!
I guess that if i was given just one more dynopull i would have reached my goal.

But, nope!
Gods of speed do exactly as they want, they don´t care about the tuners dreams ;)

I had dreams of reaching 70hp to the wheel.
I crashlanded at 69.49hp

339385339386

[peewee]

patrik who put that plating on there ? maybe send it back for warranty or better yet, a refund :cool:. I haven't tried lancourt but I think their in uk somewhere. maybe they do good job. here in the states ive used millennium every time and never one problem

[SwePatrick]

I honestly don´t know.
As in Sweden nobody is plating, there are some companies that sends to UK or Holland.
I think mine is done by someone in Holland, can´t know for sure thou :(

[ken seeber]

SwePatrick this is a clear case of shit plating, clearly no bonding to the base aluminium, as witness the flaking coming off in chunks.
However there are lots of choices. I have seen a few cylinders done by Millennium Cylinders in the US with good & economic results, but I have used NZ Cylinders (once) with good results. The latter is a bit tough to say, especially when coming from an Ozzie..:facepalm::facepalm::facepalm:

[lohring]

Has everyone seen the rev 2 new piston design video?
https://www.youtube.com/watch?v=Xpwwr0QEjuo

Lohring Miller

[husaberg]

Has everyone seen the rev 2 new piston design video?
https://www.youtube.com/watch?v=Xpwwr0QEjuo

Lohring Miller
That bully in the background is beautiful

[marsheng]

. The latter is a bit tough to say, especially when coming from an Ozzie..:facepalm::facepalm::facepalm:

Get over it you Western Islanders !!!!

[husaberg]

SwePatrick this is a clear case of shit plating, clearly no bonding to the base aluminium, as witness the flaking coming off in chunks.
However there are lots of choices. I have seen a few cylinders done by Millennium Cylinders in the US with good & economic results, but I have used NZ Cylinders (once) with good results. The latter is a bit tough to say, especially when coming from an Ozzie..:facepalm::facepalm::facepalm:

I assume swede was looking for one closer to home thn the south Island of NZ
Pitlane mentioned one most had had good results with somewhere in euroland 2nd or 3rd edition i think.

SOMEWHERE NEAR HERE I WOULD SAY
http://www.pit-lane.biz/t3173p280-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2-locked
I know it much cheaper to get done in euroville i guess just economies of scale.
Aprilia Race Dep used Tecnol to do the replating.
But as you will see here the coating used are all pretty much the same other than one used by Kawasaki

ifferent plating...
Hi...this is my very first post here....I had your address from a friend....because I work in an italian company who made aluminium cylinders with GILNISIL plating...guess which???
We made alu cylinders for Aprilia (SXV-RXV-MXV 450-550), Rotax (for Aprilia 125, 650, 1000 and BMW 650 singles but also for karts, ATV, snowmobile, ULM), BMW (boxers 850-1100-1150-1200), Cagiva (125 Mito), Husqvarna (125-250 2 stroke and 250-450-510-570 4 stroke), Piaggio (scooter engines), Moto Morini (9 1/2 and Corsaro 1200), Moto Guzzi (all models 750-1100-1200), Triumph (Bonneville serie, Daytona 675 and Rocket3) and many others, not only for motorbikes but also for chainsaws, compressors or other uses.
We have also a "replating service", where I'm responsible: I can ensure that with KTM, TM, Gas Gas, Sherco, Ducati, MV Agusta, Benelli, Honda, Yamaha, Suzuki and latest Kawasaki we use the same chemical substances we use with our cylinders. Only Kawasaki, from middle 80s till 2000-2001 used a tungsten-based plating: with these ones we must use different substances...Yes, obviously every company who have a plating department use a different name: german company Mahle started with Nickasil (or Nicasil) then GILARDONI with GILNISIL (GILardoni NIckel SILicon), BMW with Scanimet, Tecnol with CERMETAL, Suzuki's SCEM and SBC (Suzuki Ceramic Electro M...??? and Suzuki Boron Coating), Moto Guzzi (from 80s till ten years ago) with NiGuSil (Nickel Guzzi Silicon)....all based on a matrix of nickel with small particles of silicon-carbide.
Today, with Internet, you can find the instructions to make a nuclear bomb, so you can find the "recipes" of nickel-silicon plating: most important differences are in the way you plate cylinder wall and in final honing (roughness, etc).

Coming to the first question, you can replate a cylinder more than 2 time, 4-5 is not a problem for the structure...problems begin with exhaust valves seat
and holes for water joints, for example. After plating we made a sand-blasting to clean cylinders from dirt. Normally I protect critical zones with normal silicone (the classic transparent used by plumbers or carpenters); if you don't do this, after second replating valves and joints can move in its seat, with all the problems you can imagine......

I think it's enough for my first post....or not???
https://www.apriliaforum.com/forums/showthread.php?108317-Re-Plating-Cylinders

THIS IS THE POST WHERE THE GREEN EPOXY APRILIA USED IS NAMED
http://www.pit-lane.biz/t3173p300-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-2-locked

[peewee]

I tried some green putty and it's fine with petrol but with methanol it kind of turned to marshmallow. I don't know if it's the same green stuff as aprillia use. Devcon f has so far worked very well for me with methanol and nitro. For fun I bought some Devon titanium putty but have yet to try it

[pete376403]

The Chev Corvair flat 6 was an aluminium block where the pistons ran directly in the ally bore. I recall reading that they used a very high silicon alloy, and etched the bore so the particles of silicon provided the running surface (no doubt a lot more to it than that) - could that work with two stroke engines?

[Tim Ey]

The Chev Corvair flat 6 was an aluminium block where the pistons ran directly in the ally bore. I recall reading that they used a very high silicon alloy, and etched the bore so the particles of silicon provided the running surface (no doubt a lot more to it than that) - could that work with two stroke engines?

Porsche is (or was?) using the same technology.
I doubt it to be a good idea on a two stroke hence the piston ring would probably give to much pressure on the walls between ports and eat them for breakfast.

[Flettner]

https://m.facebook.com/story.php?story_fbid=1263177267154315&id=100003861602582

[Tunisti]

Hi!

I know that you guys have experience with both plated and sleeved cylinders. I have this 380 EXC witch has cracked exhaust bridges and ruined plating, and since I'm so cheap I decided to order this "universal" cylinder sleeve for hardness and elongation testing. But theres one thing that keeps bothering me - the nominal wall thickness for this sleeve it's only 1,5mm at 78mm bore, at witch I'm also intending to use it.

Do you think that the two stroke application might need thicker sleeve walls? I know that Frits isn't a big fand of sleeve applications, but are there some heat transfer/rigidity/elongation aspects that I should worry about? At least I think that the two stroke has a lot less supporting area for the sleeve, but on the other hand, with plating there's wery little thickness to bore ratio, so the thrust forces are being transmitted to aluminium bridges without load distribution.

And since we are talking about sleeves, what materials do you prefer for it? I've used EN-GJS-500-7C aka. GGG50 ductile cast iron bar for DIY cylinder's sleeve material, but would it be better to use ie. GGG40/GGG60/GGG70 or some softer grey cast iron for sleeve applications? Unfortunately the dealer of this universal sleeve had only one material info for this universal sleeve - "cast iron". Hence the testing of material...

Heres some info in form of pictures:

https://tunisti.kuvat.fi/kuvat/Random%20Pics/cyli_sleeve.jpg?img=img2048
https://tunisti.kuvat.fi/kuvat/Random%20Pics/cyli_sleeve.jpg?img=img2048
https://tunisti.kuvat.fi/kuvat/Random%20Pics/IMG-20180308-WA0031.jpg?img=img4k

By the way, what do you think about this driving of our RK-Teams 80cc air cooled track moped? It's been about 5 monts of self learning for the driver.

https://youtu.be/2gVZL3CUAFU

[Frits Overmars]

I decided to order this "universal" cylinder sleeve for hardness and elongation testing. But theres one thing that keeps bothering me - the nominal wall thickness for this sleeve it's only 1,5mm at 78mm bore...
I know that Frits isn't a big fan of sleeve applications.... Unfortunately the dealer of this universal sleeve had only one material info for this universal sleeve - "cast iron".
By the way, what do you think about this driving of our RK-Teams 80cc air cooled track moped? https://youtu.be/2gVZL3CUAFU'Not a big fan' is putting it very mildly.
I hate sleeves. And I can hardly believe a cast-iron sleeve of 78 mm bore and 1,5 mm wall thickness. I think I could crack that with my bare hands.

The rider in your video looks alright. But do you know the expression 'seat of the pants'? With a properly fastened seat he would get much more feel for the bike.
You'll never find a more effective lap time improvement.

[Muciek]

There was a guy here that did modular RD cylinder for landspeed records and he did have crazy thin sleeve . Ask him how does IT holds.
Hi!

I know that you guys have experience with both plated and sleeved cylinders. I have this 380 EXC witch has cracked exhaust bridges and ruined plating, and since I'm so cheap I decided to order this "universal" cylinder sleeve for hardness and elongation testing. But theres one thing that keeps bothering me - the nominal wall thickness for this sleeve it's only 1,5mm at 78mm bore, at witch I'm also intending to use it.

Do you think that the two stroke application might need thicker sleeve walls? I know that Frits isn't a big fand of sleeve applications, but are there some heat transfer/rigidity/elongation aspects that I should worry about? At least I think that the two stroke has a lot less supporting area for the sleeve, but on the other hand, with plating there's wery little thickness to bore ratio, so the thrust forces are being transmitted to aluminium bridges without load distribution.

And since we are talking about sleeves, what materials do you prefer for it? I've used EN-GJS-500-7C aka. GGG50 ductile cast iron bar for DIY cylinder's sleeve material, but would it be better to use ie. GGG40/GGG60/GGG70 or some softer grey cast iron for sleeve applications? Unfortunately the dealer of this universal sleeve had only one material info for this universal sleeve - "cast iron". Hence the testing of material...

Heres some info in form of pictures:

https://tunisti.kuvat.fi/kuvat/Random%20Pics/cyli_sleeve.jpg?img=img2048
https://tunisti.kuvat.fi/kuvat/Random%20Pics/cyli_sleeve.jpg?img=img2048
https://tunisti.kuvat.fi/kuvat/Random%20Pics/IMG-20180308-WA0031.jpg?img=img4k

By the way, what do you think about this driving of our RK-Teams 80cc air cooled track moped? It's been about 5 monts of self learning for the driver.

https://youtu.be/2gVZL3CUAFU

[senso]

The Chev Corvair flat 6 was an aluminium block where the pistons ran directly in the ally bore. I recall reading that they used a very high silicon alloy, and etched the bore so the particles of silicon provided the running surface (no doubt a lot more to it than that) - could that work with two stroke engines?

Some (at least older models) jet-skis also used that alloy, if I remenber the name/brand I will post it here.

[husaberg]

Some (at least older models) jet-skis also used that alloy, if I remenber the name/brand I will post it here.

I think i recall Some of the new Yams and i think the New CBR250 single use a high silicon ceramic cast in liner.

Hi Sil is bloody hard on tools though from what i understand.

YZF R15 makes use of DiASil (Die-casting Aluminum-Silicon) cylinder. The DiASil Cylinder is an all-aluminum cylinder made possible by an exclusive Yamaha aluminum forging technology. Because it uses a 20% silicon aluminum alloy, it is possible to create a cylinder wall that is so hard and durable that it eliminates the need for a conventional steel cylinder sleeve. And, because the cylinder is all aluminum, it has excellent heat dissipation qualities (cooling capacity is improved by 60% and reduces engine weight (by 30%) at the same time.


https://global.yamaha-motor.com/news/2002/0731/innovation.html

uly 31, 2002

Yamaha Motor Co., Ltd. (YMC) has succeeded in the development of an all-aluminum die-cast cylinder with 60% better cooling performance and 30% cheaper production cost than a conventional cylinder (*1). Called the Yamaha “DiASil Cylinder” (*2), this is the world’s first all-aluminum die-cast cylinder and it achieves cooling performance equivalent to that of a nickel-plated cylinder, which is currently recognized as the best in the industry, but at a significantly lower production cost than a nickel-plated cylinder.
This new cylinder is an example of the type of a new core technology that can be “strategically important in promoting future growth,” as described in YMC’s “Next 50” (*3) mid-term policy report released in April.

The new Yamaha “DiASil Cylinder” is a technology that brings together an ideal combination of material, manufacturing technology and environmental friendliness. The material used is a 20% silicon content aluminum alloy, the manufacturing technology is the recently developed Yamaha CF Aluminum Die-cast Technology (*4), which enables the production of an all-aluminum die-cast cylinder. It is Yamaha’s exclusive CF Aluminum Die-cast Technology that enables the mass production of a die-cast cylinder made completely of 20% silicon content aluminum alloy, something that could not be done with conventional die casting methods. This next-generation technology promises to contribute to improved function and product quality for the majority of Asian market motorcycles and automobiles that presently use conventional pistons with cast steel liners.

Recognizing the environment-friendly nature of aluminum, YMC has made aluminum technologies part of our core technology and actively increased the use of aluminum in our products. In February of this year, YMC introduced its new Yamaha CF Aluminum Die-cast Technology as a manufacturing technology for motorcycle chassis parts that enables the mass production of die-cast aluminum parts that are both thinner and larger than was possible in the past. Now this same technology has been applied to the manufacture of engine parts. This is also a technology that can be easily transferred to our overseas Yamaha manufacturing bases. From now on, YMC also plans to apply to new areas automobile and outboard motor engine parts.






Also a company called apitech which i have posted used squeeze formed hi sil liners although i think they still coated them.
339419
Further stuff hereplus i posted the last page later...https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130228977#post1130228977
They are a brit based outfit and do f1 stuff and repair cylinders or at least they did.
http://www.poetonaptec.co.uk/default.htm
http://www.gkn.com/Pages/default.aspx

[husaberg]

339422339421339420339423

[senso]

There is also alusil, and more names, but its all the same, high silicon content alu.

[wobbly]

The carbide embedded hi silicon alloy engine block was used by Chevrolet many years ago , and recently in Jaguar V8 .
Bioth had all sorts of headache warranty issues in places like NZ , where there was a hi Sulphur content in the fuel that ruined the bores.
But they can now be retrieved by simply honing and coating with traditional bore surface technology.

[flyincat]

Previously I said I would post pics of the mods done to the TZ400 that won at the Shorai Challenge,

Wobbly - This goes back a few years, but would you care to comment on the logic behind the radial and axial angles of the transfer ports from the Shorai TZ400? It looks like the trailing edge of the C port is pointing straight across the rear wall. Is that how it was left or was it hooked more towards the center of the bore?

[wobbly]

That engine did not have wasted studs like the 350 engine in the LSR record holding bike.
So there was simply no room at all to get a hook into the C port rear wall as the stud hole is only a couple of mm away.
Same issue with the Exhaust , it would have to have oversize wasted studs to get Aux ports into it.
The bike was ( is ) so much faster than any other Pre 82 I simply did what I could with the 350G six port cylinder and its still got too much power for the period chassis layout, as it wheelstands all the time.
The only way to keep it under control is to speed shift the thing in the lower gears at low rpm , with the front wheel just off the deck.
The 350 LSR engine started with a 250G cylinder , and that made over 100 Hp , and yes I have the spare cylinder sitting here with a mad plan to soon put that on the TZ bottom end in the Frepin frame.
The only issue is that cylinder was designed to be run backwards , and in the bike , the big 40mm Lectrons clash with the monoshock , due to the welded on reedblock angle.

[SwePatrick]

SwePatrick this is a clear case of shit plating, clearly no bonding to the base aluminium, as witness the flaking coming off in chunks.
However there are lots of choices. I have seen a few cylinders done by Millennium Cylinders in the US with good & economic results, but I have used NZ Cylinders (once) with good results. The latter is a bit tough to say, especially when coming from an Ozzie..:facepalm::facepalm::facepalm:

I´m going to move away from nicasil, this because i might tease the engine with som nitro in the future.
So i want a surface that don´t come loose ;)

Just wash away smeared aluminium with hydrochloric acid(and re-hone) if going to hot =)

[peewee]

patrick i put more than 11 liters nitro in the ktm this past summer and the nicasil (millenium) and devcon putty is doing fine. flush it with petrol at days end and youll be fine

[flyincat]

That engine did not have wasted studs like the 350 engine in the LSR record holding bike.
So there was simply no room at all to get a hook into the C port rear wall as the stud hole is only a couple of mm away.
Same issue with the Exhaust , it would have to have oversize wasted studs to get Aux ports into it.
The bike was ( is ) so much faster than any other Pre 82 I simply did what I could with the 350G six port cylinder and its still got too much power for the period chassis layout, as it wheelstands all the time.
The only way to keep it under control is to speed shift the thing in the lower gears at low rpm , with the front wheel just off the deck.
The 350 LSR engine started with a 250G cylinder , and that made over 100 Hp , and yes I have the spare cylinder sitting here with a mad plan to soon put that on the TZ bottom end in the Frepin frame.
The only issue is that cylinder was designed to be run backwards , and in the bike , the big 40mm Lectrons clash with the monoshock , due to the welded on reedblock angle.

Yes, of course, the studs! How about the axial angles and stagger? Is this a Frits-leaning-tower strategy or something completely different due to less than perfect port placement?

I also have an EngMod2T observation you may be able to explain. With the standard practice of making squish tight as practical, I thought I would see what this looks like in EngMod. It seems going from huge squish (15m/s) to tight squish (30+m/s) in EngMod doesn't seem to change the burn rate much. I'm basing this off HP, TuBMax and MaxDeg moving relatively little when making a big squish change. Compression and timing make a much bigger difference to the point the squish change seems almost negligible. Is that normal? Is there a different output in EngMod that shows the benefit of tight squish?

[SwePatrick]

patrick i put more than 11 liters nitro in the ktm this past summer and the nicasil (millenium) and devcon putty is doing fine. flush it with petrol at days end and youll be fine

Yes, i know, but that´s not the issue.
I´m making insurance if having a seize ;)
It isn´t funny to send the barrel for re-plating every once in a while, way to expensive :(

[wobbly]

The 6 port TZ350G cylinder had the A front radial increased slightly and the axials that were stock all the same were given stagger to increase the bandwidth that is limited by
the very high Ex timing and no PV ( 115 116 116.5 117 } This increased the A port upward angle the most - with 8 transfers there was no issue getting enough STA.

I have never looked at the effect of squish on the combustion data - just simply always entered the historical min height and adjusted the width to get around 38M/s.
So as an exercise I ran the RZ400 engine in Turbulent with 2mm squish = 15M/sec against the as built sim with 0.9mm = 38M/s.
All of the combustion numbers are completely different in this case ? but I havnt looked at the effect of this on power etc yet.
Though from previous experience the combustion parameters have a huge effect on the powerband shape and output.

[jbiplane]

Russian guy emigrated to USA made this amazing toy

https://www.youtube.com/watch?time_continue=90&v=n4UxBQ-LLsI
Simple idea - may be usefull for local comunity

[TZ350]

.
That 3D printer is just amazing....... :drool: ... I would love one.

[TZ350]

339444339445339446

Had an interesting project on the dyno today, Speedpro's CVT scooter.

We have had CVT engines lying around the workshop before and Cully has even made a Bucket sidecar with one. But this is the first CVT machine I have had a close look at on the dyno.

339447

It was a whole new learning curve for Speedpro and myself. We had no idea if the dyno graph is normally so erratic on a CVT, maybe its the belt flapping about. And the results of normal tuning things like changing the main jet and ignition were not very obvious. We figured we need to lock the primary pulley in some way.

If 20 hp is enough power to push the scooter through the air at 170 kmh then the speed range of 40 to 170 kmh is pretty impressive. I think I could get to like CVT's.

[Frits Overmars]

We had no idea if the dyno graph is normally so erratic on a CVT, maybe its the belt flapping about.... We figured we need to lock the primary pulley in some way.Better get rid of the V-belt altogether. You can sets of toothed belts and pulleys with the correct centre distance for most scooters at info@hvg-engineering.com


If 20 hp is enough power to push the scooter through the air at 170 kmh then the speed range of 40 to 170 kmh is pretty impressive. I think I could get to like CVT's.20 rear wheel-HP may just be enough for 170 kmh on a scooter if you have a very small rider and a straightaway over 1 km long. But I like CVTs anyway.
This is why: https://www.youtube.com/watch?v=EFjakgypqSs

[flyincat]

Wobbly - I went back and took another look in EngMod with a little more controlled experiment. It looks like I was kind of right and kind of wrong in my initial speculation. Moving the squish from high to low does have a significant affect on the TUbMax and MaxDeg, similar to the moves in compression or timing. However, the HP curve shows relatively little change from a big squish setup change (39m/s --> 15m/s). I think the most important observation of all this is the spacing of the curves on the different plots. If you consider the TUbMax penalty of adding 1pt CR vs 2* timing, the CR change seems a much better option. It appears the squish would have the least HP benefit per TUbMax penalty. In hindsight, I probably should have started MSV around 25 m/s so I could go up and down like the other variables to give a more clear picture. But, that's for another day.

Baseline - 14:1CR, MSV 39m/s, ~12* timing

339448 339449 339450

[peewee]

Yes, i know, but that´s not the issue.
I´m making insurance if having a seize ;)
It isn´t funny to send the barrel for re-plating every once in a while, way to expensive :(

that makes sense but i think you will see its not easy to seize. at close throttle the nitro makes a noise thats easy to hear its lean. lectron needles work good because you can measure the width with calipers and grind off small increments as needed. for full throttle just add some extra powerjets so you have plenty of adjustment for a wide range of conditions

[TZ350]

20 rear wheel-HP may just be enough for 170 kmh on a scooter if you have a very small rider and a straightaway over 1 km long. But I like CVTs anyway. This is why: https://www.youtube.com/watch?v=EFjakgypqSs

Interesting that 20 rwhp may be just enough. I did not wan't to fall into the trap that just because it was 170kmh on the dyno that it could achieve that on the road. I have often looked at CVT as an interesting prospect for racing. Cully has built a CVT sidecar but we have not had it on the dyno yet to try setting it up properly, so a bit to learn there yet. A CVT engine/drive in a bike is an exciting possibility if we can find a way to package it.

[husaberg]

. A CVT engine/drive in a bike is an exciting possibility if we can find a way to package it.
Yamaha Y cat
http://1.bp.blogspot.com/-O-EmtzP4_Fo/T2NaNlwTcvI/AAAAAAAABCA/sueR_2d7H7E/s1600/YCAT+MACHINE+YAMAHA+LEXAM-001.jpghttp://i232.photobucket.com/albums/ee250/android_james/img_1591.jpghttps://ninja250r.files.wordpress.com/2009/11/img_1585.jpg
Yamaha Lexam

[Muhr]

or like the 50cc freetech guys

[wobbly]

Its interesting to see the use of EngMod in a different way to how I have developed the strategies to extract best power from a project.
In reality I would never even think of actually building any engine with an MSV down at less than mid 30M/s as hundreds of dyno runs have proven that the strategy of optimizing
this variable by first using the minimum allowable mechanical depth ( just short of piston clipping ) and then varying the width ( usually around 50% ) to achieve a theoretical 38M/s always works best.
This statement assumes that an ignition system is being used that is capable of tailoring the advance to achieve the powerband shape needed for the application.

One very obvious exception would be KZ2 where only a fixed flat line " curve " is allowed , and this mandates a very low MSV to prevent the squish induced flame front turbulence from killing the much needed overev power.

But I have found that in every other case where you can tune the ignition setup , that 38M/s is always real close to optimum , be it an MX , GP or LSR type race engine.
Of course the reality is that all this is highly theoretical , as if you are actually running as close as is physically possible, then at peak rpm the squish velocity will be hugely higher ( zero gap ) , and the trapped end gases will be at a minimum volume .

In my world of supplying detailed sim information to a paying customer , I simply dont have the luxury ( read time ) to be messing about with , for example , small changes to squish velocity or duct exit Mach numbers.
I start by using what I know the dyno says will work , every time , as a baseline - and only if forced into some weird tuning corner , do i need to resort to serious " fiddling ".

[TZ350]

TZ350 Were in the garage yesterday and sanded on a PV similar to the one you have, then come and think of that you discussed it a while ago. The one I did was also cast, we preheated them to about 300 ° C and then TIG welded with 316. Also had a 3d model on nsr j20 do not know how similar it is but. Probably you've already solved it.

Thanks for the info and pictures. The later NSR blades seem to fit better so I have not tried to build a set up yet.


Oh, thats damn clever! What is the original inner and outer diameter of the SR50 Flywheel? Regards Tim

The inner diameter measured inside the magnets looks to be 85.5mm and the inner diameter of the steel shell maybe about 97mm.

[katinas]

In reality I would never even think of actually building any engine with an MSV down at less than mid 30M/s as hundreds of dyno runs have proven that the strategy of optimizing
this variable by first using the minimum allowable mechanical depth ( just short of piston clipping ) and then varying the width ( usually around 50% ) to achieve a theoretical 38M/s always works best.
.

Wobb, maybe, for best performance is some ratio between squash width and crank/flywheel inertia, conrod length.
With very light crank and ign. rotor, my engine always down on power at higher revs with 50% in comparison with 20-30%. Now I am testing with additional mass (maybe too heavy) on rotor and 50% squash, engine power at hi rpm feels better but lost too much in 8000-11000 rpm zone.
Still in tests so I am not sure.

[wax]

Damn this engine mod I cant get past the exhaust pipe error
" There is a section with a zero length that has to be fixed"
I start a new exhaust and straight away i get this. Before I throw this thing out the window does anyone have a help please

[Vannik]

Damn this engine mod I cant get past the exhaust pipe error
" There is a section with a zero length that has to be fixed"
I start a new exhaust and straight away i get this. Before I throw this thing out the window does anyone have a help please

Create a pack file, send it to me with an explanation of the error and I will fix it. It is part of the standard service when purchasing the software.

[wobbly]

The effect that having an efficiently working squish ( up at 38M/s ) is to increase the turbulence of the compressing mixture, around TDC.
This increases burn speed thru the chamber and is all but exactly the same as adding static advance.
This can be offset at higher rpm by retarding the timing in this area , to get heat back in the pipe.
Retarding the whole curve by just moving the stator is not effective as this reduces the additional midrange Hp advantage gained.
Adding flywheel inertia ( not just mass ) will increase overev capability ,up to a point , then simple physics dictates that it takes too much additional energy to accelerate
that increased rotational inertia and Hp suffers as a result.

[wax]

Create a pack file, send it to me with an explanation of the error and I will fix it. It is part of the standard service when purchasing the software.

I got it sorted, thanks it was my own dumb fault. The software is awesome, I am using an evaluation copy at the moment but I will be buying t when the month is over. It took a while to get started and to figure it out but now that I am making headway I can see the weak area in my engine and I can work on that to improve. The great thing is I can move other stuff around to try and bring them all into balance. No point having a massive power potential in one when you cant use it because of another bottle neck.
Im not so sure on the suggested carb size as I have found good low end gains by going larger. But the rest seems to be very good. I have not yet got into the wave diagrams every one posts up here

[wax]

Hey i have put my engine into engmod.
It seems i have a massive issue with the exhaust port but i can fix that. I think.
anyway to get my transfers to flow anywhere close to what im after i have to put them at 130 degrees of open time.
My sta for the blow down is still more than the transfers flow. it seems high to run the transfers, should i still just go for it ??

[flyincat]

In reality I would never even think of actually building any engine with an MSV down at less than mid 30M/s as hundreds of dyno runs have proven that the strategy of optimizing
this variable by first using the minimum allowable mechanical depth ( just short of piston clipping ) and then varying the width ( usually around 50% ) to achieve a theoretical 38M/s always works best.


Wobbly - As Mr. Box put it, "Essentially, all models are wrong, but some are useful." I'm not doubting your methodology and test results, in fact I believe those more than a model. I'm just trying to understand if the model was reflecting what you've found throughout the years. Maybe there are benefits the model doesn't account for? I'm not really sure what factors go into EngMod, besides TUbMax, octane, etc., when predicting detonation. You've mentioned with tight squish, approaching zero, there isn't any mixture left to detonate. If TUbMax approaches critical detonation temperature, but there's nothing, or very very little, left in the squish maybe detonation doesn't happen in real life? Perhaps Neels can comment on the detonation prediction for a special case of near-zero squish.

[peewee]

Hey i have put my engine into engmod.
It seems i have a massive issue with the exhaust port but i can fix that. I think.
anyway to get my transfers to flow anywhere close to what im after i have to put them at 130 degrees of open time.
My sta for the blow down is still more than the transfers flow. it seems high to run the transfers, should i still just go for it ??

i havent any idea what cylinder youve got but you might try widening them before raising them to the clouds. right now im in the process of doing just that, so the B can farther around back. of course these shitters have no excess material to work with so i have to cut open the water jacket and weld. finished welding couple days ago and just need to cap the holes. photo is after cutting the windows but before any welding

[wax]

i havent any idea what cylinder youve got but you might try widening them before raising them to the clouds. right now im in the process of doing just that, so the B can farther around back. of course these shitters have no excess material to work with so i have to cut open the water jacket and weld. finished welding couple days ago and just need to cap the holes. photo is after cutting the windows but before any welding
There isnt much in the way of room to widen them. My sta for blow down is more than enough for the projected power.
So i figured that it would be ok ??

[jonny quest]

I've always wondered why the OEM's would run 2mm of squish clearance on they're motors?

Last generation of Honda CR 250R motocross single cylinder was notorious for this.

What was their reasoning?

[husaberg]

I've always wondered why the OEM's would run 2mm of squish clearance on they're motors?

Last generation of Honda CR 250R motocross single cylinder was notorious for this.

What was their reasoning?
Production tolerences, they have to allow for the worst combination of parts
cylinder length
conrod length
piston height
gasket thickness. etc

if you add in the tallestest and thickest of these parts what was set at 1mm can become 0.0mm rather quick.
pistons and big ends and crankpins are coded in dia size to accommodate production variance but not in length.
As it was the last models Honda likely also got sloppier than normal.

[jonny quest]

I used to think that too, Husa.

But 2mm! I've checked the squish on many of these stock, and they're all the same. I don't think it's production tolerance they were after

[jonny quest]

Has anyone tried port filling with map gas and aluminum brazing rod?

[TZ350]

339489 339490

Made a direct big end oiling pump for the Beast from a micro peristaltic pump and mini VSD drive.



339318 ... direct B/E oiling modification.


339239 back together again after replacing the rod kit and using a special crank pin Flettner made for me that has direct posi lube oiling to the big end.

[F5 Dave]

I used to think that too, Husa.

But 2mm! I've checked the squish on many of these stock, and they're all the same. I don't think it's production tolerance they were after

I used to believe Graham Bell's explanation (1st testament, the bit people have to take with a grain of salt.. . .still waiting for 2nd. Just throwing it out there:msn-wink: ). But without exception every bike I've checked if any got slightly near a reasonable squish through these means (tolerance stack up), the compression ratio would cause a string of detonation warranty claims that didn't go away with new parts.

My GasGas 300 for example cut to a safe 1mm was edging towards 17:1. You have to twist thick solder together to get a measurement as its well over 2mm.

[peewee]

Has anyone tried port filling with map gas and aluminum brazing rod?

few yrs ago before i bought a welder i tried the braze rod and map gas on some scrap cylinders. im no professional with that stuff but its not very suitable for engine stuff, other than maybe plugging a casting pinhole on the exterior, but epoxy could plug the hole just as easy and be cheaper and less hassle

when doing build up, which is near impossible, the previous layer of rod will melt off like solder when trying to apply a top layer. its weird stuff and a pain in the neck imo. also it doesnt fuse into the parent material like a weld does either. seems like ive got some still laying around if you want it but for god sakes just dont try sending it back to me :crazy:

[TZ350]

339493
.
.
I have finally got the simulator working and the modified Speeduino code that reads the MAP sensor working properly.


I now have a fuel injection system that measures the high and low pressures in a two strokes crankcase and displays the difference as a valid MAP reading that the Speeduino can use in its other tables. Currently no other fuel injection system uses this approach.


The next step is to get the Speeduino hardware installed on the bike and give it a twirl on the dyno to see if we have got rid of that pesky problem with coming back on the throttle again after shutting off from a WOT run. This throttle response problem has been what has defeated previous attempts by many people who have tried their hand at fuel injecting high performance two strokes. If my idea of using the difference between high and low crankcase pressure as a MAP value works. It will be as far as I know the worlds first ever publicly accessible EFI firmware that works for high performance two strokes that run above 10,000rpm and make more than 10bar BMEP by heavily relying on their pipe resonance for making power.


The MAP value varies depending on the difference between the High and Low pressures in the 2S crankcase. Close the throttle and the difference is less and the MAP value is lower. Open the throttle and the difference increases and the MAP value goes up. Just like it does with a 4T.
.

[TZ350]

.

World beating super shit hot two stroke fuel injection is old hat now. This could be Team ESE's next Side Car project.
.

<iframe width="560" height="315" src="https://www.youtube.com/embed/14iO9c7aars" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>

[husaberg]

.

World beating super shit hot two stroke fuel injection is old hat now. This could be Team ESE's next project.
.

<iframe width="560" height="315" src="https://www.youtube.com/embed/14iO9c7aars" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>
thats 90cc each cylinder me thinks. they got me another time.

[Frits Overmars]

World beating super shit hot two stroke fuel injection is old hat now. This could be Team ESE's next Side Car project.Then we'd better provide you with some more pictures of the beast.

339494 339495 339496 339497 339498 339499

[Frits Overmars]

And some more.
339510 339509 339511 339508 339506 339507

[peewee]

Then we'd better provide you with some more pictures of the beast.

339494 339495 339496 339497 339498 339499

hey frits in that first photo is that what wobbly keeps refering as wasted studs?

[Frits Overmars]

hey frits in that first photo is that what wobbly keeps refering as wasted studs?Looks like it, doesn't it? But in Wobbly's case (pictures below) they really are studs, holding the cylinders and the heads down.
In the Maxiscoot cylinder they are merely filler bars, hanging from the head cover; they have no connecting function.
339512 339513

[husaberg]

Looks like it, doesn't it? But in Wobbly's case (pictures below) they really are studs, holding the cylinders and the heads down.
In the Maxiscoot cylinder they are merely filler bars, hanging from the head cover; they have no connecting function.
339512 339513
I thought the maxiscoot ones locked into underside od the bottom allen bolt "studs" and then hold the head on,
If not is there only reason for being to provide access for the to closely spaced 50cc stud pattern?
If thats the case why attach them to the head a all?

[Frits Overmars]

I thought the maxiscoot ones locked into underside od the bottom allen bolt "studs" and then hold the head on, If not is their only reason for being to provide access for the too closely spaced 50cc stud pattern?They provide access to the studs and they fill the space above those studs in order to create decent flow paths for the auxiliary exhaust ducts and the B-transfers.


If thats the case why attach them to the head a all?Where else? You can't just screw them into the cylinder; they need to be held in a fixed position. The small pins indicated by the arrows are taking care of that.
339515

[ken seeber]

And some more.
339508 339506 339507

Frits, looks like a neat bit of intersitial engineering (ie filling the gaps).

Now the reed block manifolds. Are these nylon of some sort and were they moulded, 3D printed or machined from solid?

[Larry Wiechman]

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=339495&d=1542316000

I just noticed the keyslots in the casting.

I'm going to guess that the patent holder, Michael Burgard, is a moldmaker by trade.

[F5 Dave]

I am so sick of our Sla 3D printer. Bane of my life.

Ok. . . Not as bad as the accountant.

[Frits Overmars]

Frits, looks like a neat bit of intersitial engineering (ie filling the gaps).
Now the reed block manifolds. Are these nylon of some sort and were they moulded, 3D printed or machined from solid?They're 3D-printed. I don't remember the type of material.


I just noticed the keyslots in the casting. I'm going to guess that the patent holder, Michael Burgard, is a moldmaker by trade.Guess again, Larry. Burgy is a two-stroke developer by trade; has been all his life.

[shnaggs]

You can't just screw them into the cylinder; they need to be held in a fixed position. The small pins indicated by the arrows are taking care of that.
339515


Who says they need to be fixed???:Punk:

[Frits Overmars]

Who says they need to be fixed???:Punk:That was me, wasn't it? Are you thinking of doubling their function and rotate them like throttle valves, Shnaggs? Good idea :2thumbsup

[shnaggs]

That was me, wasn't it? Are you thinking of doubling their function and rotate them like throttle valves, Shnaggs? Good idea :2thumbsup

I was actually :yes:

[oldjohnno]

Here's a thought: if the cylinder could be locked down with horizontal cams through the top of the cases acting on lathe chuck style pins, then there'd be no need for
openings through the barrel at all. The head would be held down with short capscrews and the pins in the base of the barrel would only need to be screwed in maybe 15 - 20mm deep. It might allow more freedom in port layout and the camlock setup has proven to be very secure in holding on a chuck.

https://imgur.com/NeURSpB

An alternative would be external tierods - this would eliminate the head and barrel fasteners altogether in the port areas.

[JanBros]

339511

almost all cylinders have the C-port extending below BDC, what is the benefit of that ?
doesn't the moving piston create unwanted turbulence ?

[Muhr]

They claim 250 kg of clamping force per piece:2thumbsup

https://m.youtube.com/watch?v=IR820heX2_w

[Ocean1]

Here's a thought: if the cylinder could be locked down with horizontal cams through the top of the cases acting on lathe chuck style pins, then there'd be no need for
openings through the barrel at all. The head would be held down with short capscrews and the pins in the base of the barrel would only need to be screwed in maybe 15 - 20mm deep. It might allow more freedom in port layout and the camlock setup has proven to be very secure in holding on a chuck.

I'll just point out, here that a thread is just a helical wedge....

[husaberg]

No good to us as two stroke rings are far to high compared to the gudgeon but interesting concept
The pin buttons are retained by the oil ring
339540339543339542

I seen this pic as well its a Russian V12 warbird it must be pressed in but the buttons ends look aluminim i thought it was retained from ther inside with pis but it doesnt appear to be.
339538339539339541

[TZ350]

339544 339545

The big move now is to strip out the old Ecotrons ECU and fit the new Speeduino unit with my modified sensors firmware. Looks easy but will take a night or three.

[TZ350]

339546

Goodby to an old friend, the Ecotrons ECU. Without meaningful support from Ecotrons, and with their help dept a nightmare to deal with, I have given up on them. After a lot of careful work I have to say that their 2S EFI system as it is, with its limitation of only being able to run a Alpha-N map is useless for high performance two stroke fuel injection. This thread goes into the technical details of why Alpha-N is not enough:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

[jamathi]

almost all cylinders have the C-port extending below BDC, what is the benefit of that ?
doesn't the moving piston create unwanted turbulence ?

There is no benefit at all!

[Larry Wiechman]

https://www.kiwibiker.co.nz/forums/attachment.php?attachmentid=339540&d=1295432378

What is the function of the port above the wrist pin? (Not the lube slot.)

[Frits Overmars]

What is the function of the port above the wrist pin? (Not the lube slot.)Look carefully Larry. They're not ports, they're just pits for weight-saving purposes.

[jamathi]

Look carefully Larry. They're not ports, they're just pits for weight-saving purposes.

And totally useless, I hate them

[jasonu]

Has anyone tried port filling with map gas and aluminum brazing rod?

I doubt you would get it hot enough.

[jasonu]

339546

Goodby to an old friend, the Ecotrons ECU. Without meaningful support from Ecotrons, and with their help dept a nightmare to deal with, I have given up on them. After a lot of careful work I have to say that their 2S EFI system as it is, with its limitation of only being able to run a Alpha-N map is useless for high performance two stroke fuel injection. This thread goes into the technical details of why Alpha-N is not enough:- https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

Be sure to tell them so.
And direct them to this thread.

[TZ350]

Be sure to tell them so. And direct them to this thread.

Good Idea. I sent Matt of Ecotrons links to this thread and this other one too, which is all about my new Speeduino EFI system. https://www.kiwibiker.co.nz/forums/showthread.php/185773-Speeduino-2T-EFI-Project

I have been doing a lot of work they could have benefited from, their loss I recon.

[TZ350]

339595

Got the Speeduino mostly wired in. I had forgotten the IAT and CLT temperature probes. And I still have to figure out how to incorporate the old wide band oxygen sensor. And I am still going to use the Ignitec ignition because it has a lot 2S specific things like a 3D mapped TPS based ignition and PV power valve controller. To use the Ignetec, my plan is to have the Speeduino fire continuously at a fixed 15 deg BTDC to mimic the old Ignitec pickup.

Hopefully I will get to see if we can kick the old girl into life tomorrow night.

[jbiplane]

Goodby to an old friend, the Ecotrons ECU.

Hi Tz350. We used Ecotron few years ago and have to develop our proprietary system SmartEMS. May be its already suit you. Push me by jbiplane@gmail.com with all your wishes.

[peewee]

hey fellers I have some small progress and some questions for my next move. first two photos is just material I put at the rear of B and the caps welded back on.

third photo is just showing the longer exh passage and shell that ill use, along with a removable exh spigot, attached with three or four bolts.

fourth photo is showing what I think I could do with the water. spigot (red) will be welded to end of exh and the radiator hose can connect to it and carry on the the radiator top. does this seem like a reasonable method of routing the water ?

last photo . something keeps telling me to put epoxy on the front wall of B (right side of photo) so the charge goes more straight in the cylinder. then since I added material at the rear of B in the water jacket , ill be able to widen the window around back and make more of a radius turn into the cyl. I think this should increase the flow width, rather than keeping it like original (left side of photo). what do you think ?

[husaberg]

Not really the place but the widest audience anyway
Anyone know the dimensions for a DR370/SP370 conrod?
Best i can make out is 32mm crankpin 20mm wristpin

[Nath88]

339595

Got the Speeduino mostly wired in. I had forgotten the IAT and CLT temperature probes. And I still have to figure out how to incorporate the old wide band oxygen sensor. And I am still going to use the Ignitec ignition because it has a lot 2S specific things like a 3D mapped TPS based ignition and PV power valve controller. To use the Ignetec, my plan is to have the Speeduino fire continuously at a fixed 15 deg BTDC to mimic the old Ignitec pickup.

Hopefully I will get to see if we can kick the old girl into life tomorrow night.

Awesome stuff, keen to see this happen. Also impressed by the oil pump, how slow does she go?!
I'd really love a small reliable pump, the KTM Mikuni pump was looking good but even they seem to be having lubrication failures. Considering just driving an old school mechanical pump with a servo motor.

Regarding the ignition, I was thinking of triggering my stock ignition the same way, mimic either the leading edge (to let the external ignition handle timing through its internal delay) or the trailing edge (to bypass the external ignition timing, giving full ECU control).
I was thinking to use a small signal transformer, to provide isolation between the ECU outputs and the floating pickup input to the external ignition. As the ECU switches the output to the transformer on and off you'll get a pulse one way, then the other on the output. Then use a diode to block the unwanted edge.

My engine is still sitting on the bench until I can afford to plate the cylinder and have the injector bungs welded in. :(

[s.reginaud]

made my own Excel to calculate FOS-pipes :

http://users.telenet.be/jannemie/FOS%20pipe%20black.bmp

calculates the latest FOS pipes, you can add a Wobbly exhaust duct, and compare the original FOS-pipe with 2/3 stage versions.

the 3 pipes can be overlayed in the graph so it is very easy to compare them.

free for all : http://users.telenet.be/jannemie/FOS%20PIPE%20black.xlsm

if the experts would like to read the text on page 2 to make sure I'm not talking jibberisch :weird: , I would be even more thankful :not:

hello!
im just curious about your calculator, lets say that for a 125 the goal was 30hp at 11.000 rpm the baffle stinger would be 17mm and then if the goal the was 50hp at same rpm then the baffle stinger would be 21.9 and that is the only factor that is changing when increasing the hp?
and as i have understand it, isn't "almost" the opposite way it should go?
best regards Reginaud.

just a little edit. can se that its just how the fos concept calculate the restrictor. but lets say that i would like to make a exhaust for my 50cc with just 10 hp at crankshaft then the restrictor will only be close to 10mm isn't that dangerously small?

[TZ350]

... the oil pump, how slow does she go?! Considering just driving an old school mechanical pump with a servo motor.

At 50% it is to fast, any slower and there is not enough starting torque. I would think the peristaltic pump driven by a stepper motor would be ideal. I was going to add a PWM timer to mine. But your idea looks better and could be matched to engine rpm and throttle position, that would be just the Bee's Knees.


Regarding the ignition, I was thinking of triggering my stock ignition the same way.

I tried my ignition idea tonight. It would spark a few times then stop. I think the Ignitec ignition input is a very high impedance and the Speeduino output is also a very high impedance when its switched low. So things get pumped up to 5 Volts and the Ignitec does not get to see a low voltage and re set itself. Tomorrow night I am going to tie the Speeduino's ignition output to earth with a resistor. hopefully that will allow a reliable 0 to 5 and back to 0 Volts swing at the Speeduino's ignition terminal.

I like your small coil idea and I will adopt that as my plan B, thanks for the suggestion.

[JanBros]

hello!
im just curious about your calculator, lets say that for a 125 the goal was 30hp at 11.000 rpm the baffle stinger would be 17mm and then if the goal the was 50hp at same rpm then the baffle stinger would be 21.9 and that is the only factor that is changing when increasing the hp?
and as i have understand it, isn't "almost" the opposite way it should go?
best regards Reginaud.

just a little edit. can se that its just how the fos concept calculate the restrictor. but lets say that i would like to make a exhaust for my 50cc with just 10 hp at crankshaft then the restrictor will only be close to 10mm isn't that dangerously small?

It is not my concept, so don't ask me any questions about it . All I did was add a Wobbly-duct and make the multiple sections with adjustable sliders.

and it's only a concept, not meant to design full-factory pipes. Besides, if you extract 20BHP more, I suspect your exhaust gases are hotter so you need to change that to and more stuff will change besides the stinger dia.

just yesterday, Frits answered your question on Pitlane ;-)

http://www.pit-lane.biz/t6246p525-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

[s.reginaud]

It is not my concept, so don't ask me any questions about it . All I did was add a Wobbly-duct and make the multiple sections with adjustable sliders.

and it's only a concept, not meant to design full-factory pipes. Besides, if you extract 20BHP more, I suspect your exhaust gases are hotter so you need to change that to and more stuff will change besides the stinger dia.

just yesterday, Frits answered your question on Pitlane ;-)

http://www.pit-lane.biz/t6246p525-gp125-all-that-you-wanted-to-know-on-aprilia-rsa-125-and-more-by-mr-jan-thiel-and-mr-frits-overmars-part-5

thanks for the answer! im just trying to understand the FOS concept, cause we are currently building a new motor for our classic 50cc racer, and i want to find out which exhaust calculations to use for it. and to learn more about expansion exhausts :)

[TZ350]

<iframe width="560" height="315" src="https://www.youtube.com/embed/CJBG7k3DIms" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Stem power looks the go, what are the rules for a Steam powered Bucket???? ...... :scratch:

[F5 Dave]

P-p-put the kettle on Granville.

And if you crash try not to get stuck under the bike. ouchie!

Fogging visors will be an issue even on dry days.

[TZ350]

339619

Ok, I have been able to get the Speeduino number 1 ignition output talking to the Ignitec crank sensor input by putting in a 10K Ohm resistor that pulls the Speeduino output / Ignetec input to 0 volts between ignition pulses that way the Ignitec can see the start of the next ignition event.

When I tried to start it the bike gave a few splutters and coughs so it might start to run properly when I get the fuel map dialed in, fingers crossed.

[wobbly]

Regarding the stinger size in the FOS spreadsheet.
Understand that this can only ever be a guide to a good start point for any pipe project , and that the only way to get anything really close is to analyse the design fully in EngMod.
By looking at the gas Mach in the stinger you can optimize the design , BUT the stinger size is dependent upon a very wide range of parameters ,and as such can have a wide range of optimum sizes.
As a general rule , the greater the bmep the higher the mass gas flow thru the engine ( delivery ratio ) thus a bigger stinger is needed to maintain the optimum pipe residual pressure.
Having a 21.9mm stinger on an Aprilia making only 50 Hp would be fine , go to the real numbers of 55Hp and closer to 23 ( what the factory used ) would be optimum for road racing.
But again , as a general rule , the bigger the stinger , the better the power is , in the lower mid range as the reduced back-pressure reduces the pipes efficiency when the return wave comes back too early.
This is what is needed in MX , so the road racing smaller stinger would not be optimum.
A TM kart engine makes 2 Hp more at 9,000 with a 24mm stinger , but makes 2 Hp more at 13,500 with a 22.8mm insert nozzle in that same pipe.
Nothing is close to a free lunch.
How the hell can a simple spreadsheet accommodate all those variables - it cant , obviously.

[Frits Overmars]

Wob, I completely agree with all of the above. But I think I need to clarify a thing or two.
As far as I'm concerned, there is no FOS spreadsheet; I've never published a single spreadsheet in my life.
I posted the simple drawing shown below, called 'FOS exhaust concept', and several people built a spreadsheet around this drawing and called it a 'FOS spreadsheet'.
Maybe I should feel flattered, but I'd rather wish they hadn't. To begin with, I kept my concept so simple that nobody should need a spreadsheet wrapped around it.
Over time I made some small adjustments, but not all these spreadsheets were brought up to date, so now there are different confusing versions around.
And finally, those spreadsheets were regrettably posted without my accompanying text, which read:
The 'FOS exhaust concept' is only meant to help beginning tuners on their way. Many important factors, like compression ratio, ignition timing, type of fuel, carburetter diameter, crankcase volume and angle.areas, are not taken into account.
Instead of all those factors that I left out, I included one variable, the speed of sound. Starting with 550 m/s will get you in the right ballpark, after which you can vary this value according to your findings.
You should not use this simple exhaust concept to improve on the highly developed RSA engine, where all of the above-mentioned factors were taken into account.
Final remark: the calculation of the tailpipe restrictor diameter is critical: you can only apply it to engines that are thermally sound. Air-cooled engines are not.339638

[marsheng]

P-p-put the kettle on Granville.
.

New video title, "30 seconds of boat and 9 minutes of old farts wading in a pond." The local fish must have got dizzy. Great achievement anyway. .

[marsheng]

Anyone made front fork tubes with 4130 Chrome molly tube. There is some 3 mm wall thickness stuff for sale which looks promising. The 1964 Duke I'm working on has 31.5 mm tubes and new are US$500 plus postage !!! Only found one supplier so far. Next option is to bore the fork legs out to 32 mm and use a GN125 set. .

[JanBros]

@ Frits :

a spreadsheet is so much easier than calculating again and again, and you can see the pipe change with different data which is more efficient than numbers that change. And with a click you can compare different pipes.

It should contain your latest version (0.34/0.32/0.08/0.26 L factors) and your drawing is included, as is Wobbly's duct.

I will add your accompaning text ;-)

[Frits Overmars]

Jan, my main objection was that not everybody keeps the concept updated. Did you also catch the "D5=3,1 * ...." ? That was my most recent adjustment.

[JanBros]

Did you also catch the "D5=3,1 * ...." ? That was my most recent adjustment.

indeed , I did :yes:

[Frits Overmars]

the greater the bmep, the higher the mass gas flow thru the engine (delivery ratio) thus a bigger stinger is needed to maintain the optimum pipe residual pressure.The greater the BMEP, the higher the mass gas flow per revolution through the engine. Past max. torque_rpm the BMEP and the mass flow per revolution will drop,
but since the revs are still increasing, the mass flow per second can still increase, together with the power. Hence the direct connection between crankshaft power and restrictor area in my exhaust concept.


The bigger the stinger, the better the power is in the lower mid range, as the reduced back-pressure reduces the pipe's efficiency when the return wave comes back too early.
This is what is needed in MX , so the road racing smaller stinger would not be optimum.
A TM kart engine makes 2 Hp more at 9,000 with a 24mm stinger, but makes 2 Hp more at 13,500 with a 22.8mm insert nozzle in that same pipe. Nothing is close to a free lunch.You're right, of course. And even on the Aprilia RSA, with all those goodies that you're not allowed to use on a kart engine, like electronic power valve, pulsed power jet and 3D-ignition timing, a less restrictive restrictor could have its use. That is one reason I designed the restrictor-bypass shown in the drawing below (the other reason was to avoid high-rpm part-throttle detonation). But Jan Thiel retired before it could be put to the test.
339641


How the hell can a simple spreadsheet accommodate all those variables - it cant, obviously.It can't, and it's not supposed to. Like I wrote, it's just a simple concept, meant to help beginning tuners on their way.

[jasonu]

Anyone made front fork tubes with 4130 Chrome molly tube. There is some 3 mm wall thickness stuff for sale which looks promising. The 1964 Duke I'm working on has 31.5 mm tubes and new are US$500 plus postage !!! Only found one supplier so far. Next option is to bore the fork legs out to 32 mm and use a GN125 set. .

Option B sounds easier and more likely to work.

[wax]

Is there an optimal pressure in the pipe. My thinking is can we then make a bellows that opens and closes the stinger diameter to allow you to maintain the perfect pressure.. I understand that what you were looking at Frits but im talking about having it constantly adjustable

[F5 Dave]

Was to suggest fed from Det counter but that would be way to late for a mechanical device to react I guess.

Didn't TZ try a midpipe solenoid bleed? Or did I dream that? No there's a picture in my head.

[wobbly]

You dont want " constant " pressure in the pipe.
Jetski racing uses a very large stinger , to get a very low residual pressure at low rpm that pumps up the midrange power.
Then using PWM or rpm switches they turn off solenoids that allows high pressure water to dump into the stinger , squeezing down the effective area , and thus increasing the pipe back pressure around peak power.
This works really well.

[Ocean1]

You dont want " constant " pressure in the pipe.
Jetski racing uses a very large stinger , to get a very low residual pressure at low rpm that pumps up the midrange power.
Then using PWM or rpm switches they turn off solenoids that allows high pressure water to dump into the stinger , squeezing down the effective area , and thus increasing the pipe back pressure around peak power.
This works really well.

You'd probably want to be up front somewhere before pulling that trick on a bucket though, eh?

[wax]

You dont want " constant " pressure in the pipe.
Jetski racing uses a very large stinger , to get a very low residual pressure at low rpm that pumps up the midrange power.
Then using PWM or rpm switches they turn off solenoids that allows high pressure water to dump into the stinger , squeezing down the effective area , and thus increasing the pipe back pressure around peak power.
This works really well.
Thanks Wobbly i know I will always get a good response from you. Yes i inject water in to my stinger to try and get more top end. I was thinking about trying to regulate that by pressure in the pipe , had you come back saying yes you need this pressure

[SwePatrick]

Stinger diam.

I´ve seen in simulations and in my dyno that a stinger that is 'correct' for peak power is almost always to small for a wide powercurve.
Well,,that is a known fact.
But the losses vs gains is so small with having, say a 250cc engine single cylinder that needs a 25mm stinger to reach maximum peak power, it will loose like 1hp at peak and gains 4-5hp in midrange if having 26mm stinger.

I choose the later.. more torque is good.
When having a very peaky engine one has always a 'dead' engine before hitting powerband.
And almost always when looking in my dynodata, i see more average power in used powerband with the later example.

[jbiplane]

I find this description on Ecotron site

2-Stroke Small Engine Fuel Injection kit is designed to run 2-stroke small engines. This kit can drive 2 injectors per cylinder (one big injector, one small injector). During idle, and low part loads, ECU only opens the small injector for small fuel quantities; it will switch to the big injector for mid, or mid-high loads; and it will activate both injectors at WOT conditions. The transitions between the injectors are transparent to the driver and they are so smooth that the driver can not feel it. This setup controls the accurate AFR (lambda) from idle all the way up to 16000RPM. We have a

The whole idea of 2 injectors (one small, one big) is based on the need: 2-stroke engines have only half the time to inject fuel compared to 4-stroke (360 vs 720 degrees), and the 2-strokes usually (esp. high-end engines) have such a wide range of RPM (2000 - 16000rpm, for example). One injector is not able to cover the whole RPM range, simply because every injector has its physical limit: the fixed flow rate. If you use a big injector to cover the high end, then you will have too-rich idle. If you use a small injector, to have a good idle, then you don't have enough fuel for WOT. Given a certain inject flow rate, you can only run an engine either at low RPM range or high RPM range, but not both (from 2000 to 16000rpm).
For example, an engine runs at 16000rpm, you only have max 3.75ms time-window to inject fuel. In this short time, you have to inject enough fuel for WOT conditions. If you pick a super big injector, you will not be able to run idle (too rich even at 1ms pulse width). So what can you do? add more injectors. At low load, use one injector, and at high load/high RPM, use 2 or more injectors. That's why you see a lot of racing engines have 2,3, or even 4 injectors per cylinder. Our system is better: while others use the same size of injectors, we use one small, one big injector. Why? because at idle, you need a very small size of inject, and at WOT, you need a big size. The benefits: you can run the engine at ideal AFR over the whole wide range of RPM, with only 2 injectors (again, save cost compared to 3 or 4 injectors). The tansitions from idle, to WOT, will be: the small injector works at idle, low load; then it switches to the big injector at mid-high load (the small one shuts off); then at WOT both injector works together. And all these are made transparent to users!
This is our unique technology for 2-strokes, not even big companies have this.

I want to implement same or similar in my EFI. Is this specs rational enough or someone advice corrections?

[TZ350]

I find this description on Ecotron site. I want to implement same or similar in my EFI. Is this specs rational enough or someone advice corrections?

Yes totally on the money but only half the story.

Ecotrons use the Alpha-N topology for their 2S fueling map and it works well on 2S's that are not very pipe dependent like 250cc Enduro bikes but Alpha-N does not support high performance 2S's like GP125's where they make a lot of power through clever use of their pipe.

Because Alpha-N is a fixed pre determined fuel squirt amount for every TPS vis RPM cell on the MAP. This only works half the time for a high performance GP engine because AN cant be both correct for when the engine is on the pipe and when it is not.

I use the 10/10 concept. Anything less than 10,000 RPM and 10 bar BMEP is probably possible with an Ecotrons but anything making more than 10 bar BMEP and 10,000 RPM needs something more sophisticated for their fuel mapping. Having said that, in my experience Ecotrons will fuel accurately to 13,000 rpm on WOT but the problem arises when you throttle off and the pipe resonance collapses. AN fueling can't cope with the change in air flow.

My current EFI 2S efforts are aimed at solving this and am looking for ways to see the actual changes in airflow through the crankcase. Currently I am looking at the difference between maximum and minimum crankcase pressure and how it changes when the engine gets on or comes off the pipe.

[peewee]

hey guys I did a lot of pencil work and made a 2d drawing to scale so hopefully I can get it right or mostly right the first time :laugh: . based on port area at the bore and spigot ID, ill have a 35mm x 43mm oval half way down the passage which will transition toward a round 36mm spigot exit. I chose 35 x 43 because I think that will be the best compromise with least amount of welding inside the passage so the cyl skirts have less chance of warping. aux ears will carry on to 10mm before the spigot entrance at which time it will be fully round passage about 38mm ID then go through the spigot to 36mm at exit. im ready to start cutting and welding now but something I recently thought of, since the duct and outer water shell will be so long I have to first check with the local machinist and be sure he is able to machine the top and bottom decks and bore it without any interference of it sitting flat on his machine table. I hope this isn't the case but other wise I may have to make the whole duct assembly removable with bolts near the half way point and that will be a real pain in the ass

[jbiplane]

Ecotrons use the Alpha-N topology for their 2S fueling map and it works well on 2S's that are not very pipe dependent like 250cc Enduro bikes but Alpha-N does not support high performance 2S's like GP125's where they make a lot of power through clever use of their pipe.

Thanks for valuable comments. Will try follow your ideas!

[Norman]

You're right, of course. And even on the Aprilia RSA, with all those goodies that you're not allowed to use on a kart engine, like electronic power valve, pulsed power jet and 3D-ignition timing, a less restrictive restrictor could have its use. That is one reason I designed the restrictor-bypass shown in the drawing below (the other reason was to avoid high-rpm part-throttle detonation). But Jan Thiel retired before it could be put to the test.
339641

Thinking :rolleyes:about this problem with high "rpm part-throttle detonation". Could it help if one would combine the above restrictor bypass with an ATAC and a Suzuki type tripple blade exhaust valve (for example) where the third, top blade, would be higher up than normal and used to only be opened together with the ATAC valve at high rpm part throttle situations? It would relief the cylinder pressure earlier and the ATAC would change resonance such that return wave will be delayed (weakened?) and the restrictor-bypass lowers the magnitude of any moving pulses?

[Norman]

Second blade..as the third blade is not moving, just for filling out the top.

[Frits Overmars]

Thinking :rolleyes:about this problem with high "rpm part-throttle detonation". Could it help if one would combine the above restrictor bypass with an ATAC and a Suzuki type tripple blade exhaust valve (for example) where the third, top blade, would be higher up than normal and used to only be opened together with the ATAC valve at high rpm part throttle situations? It would relief the cylinder pressure earlier and the ATAC would change resonance such that return wave will be delayed (weakened?) and the restrictor-bypass lowers the magnitude of any moving pulses?Yes, increasing the blowdown angle.area beyond its present value would help counteract the high-rpm, part-throttle detonation, Norman. Your third blade (the Aprilia cylinder already has two blades) would also clutter up the shape of the exhaust port timing edge, which would cost power everywhere, and it would interfere with the coolant access around the exhaust port.

[Norman]

Yes, increasing the blowdown angle.area beyond its present value would help counteract the high-rpm, part-throttle detonation, Norman. Your third blade (the Aprilia cylinder already has two blades) would also clutter up the shape of the exhaust port timing edge, which would cost power everywhere, and it would interfere with the coolant access around the exhaust port.

Yes Frits, you are right, the timing edge there will not be so good..:facepalm:

[Peter1962]

You're right, of course. And even on the Aprilia RSA, with all those goodies that you're not allowed to use on a kart engine, like electronic power valve, pulsed power jet and 3D-ignition timing, a less restrictive restrictor could have its use. That is one reason I designed the restrictor-bypass shown in the drawing below (the other reason was to avoid high-rpm part-throttle detonation). But Jan Thiel retired before it could be put to the test.
339641


Frits, your concept of a variable tailpipe / restrictor-bypass was probably born with the idea to implement it on the absolute top performing two stroke engines at that time : the 125 cc GP engines and even the best at that : the RSA by Jan Thiel. What do you think of a possible use in other categories, like MX ? Do you think that your system could benefit a modern 250 2 stroke engine, of course when coupled with a well designed exhaust ?
The 250's are not that far behind a 450 foulstroke, but they suffer very badly from a less usable (more narrow) powerband compared to the newest 4 strokes.
Could your system be a way to broaden the powerband of an existing MX bike ?

[dutchpower]

Wel designed exhaust 262 cc 2 stroke ( were are the 450 fourstroke :motu: )

https://www.youtube.com/watch?v=38aIL9f_G7k

[Frits Overmars]

Frits, your concept of a variable tailpipe / restrictor-bypass was probably born with the idea to implement it on the absolute top performing two stroke engines at that time : the 125 cc GP engines and even the best at that : the RSA by Jan Thiel. What do you think of a possible use in other categories, like MX ? Do you think that your system could benefit a modern 250 2 stroke engine, of course when coupled with a well designed exhaust ?For an engine without a power valve I would not hesitate to say yes, but I don't think we'll find a single MX-bike without a power valve these days.
The restrictor bypass will no doubt counteract high-rpm part-throttle deto on any engine, but those MX-bikes are not that highly strung: a 250 cc MX-engine makes less power than a 125 cc GP-roadracer, so maybe they haven't got that deto problem. You'd have to try it, Peter. And let us know what you find :msn-wink:.

[TZ350]

Hello,
I just registered in this forum as I saw this very interesting topic. I'm glad to see someone is trying and sharing his ideas.
I built my own 2S EFI for my racing Solex (a very particular 50cc here in France).
The beginning is very encouraging, take a look : https://www.youtube.com/watch?v=LW19l64nm7Y.

I love it...... a fuel injected Solex racer.

<iframe width="560" height="315" src="https://www.youtube.com/embed/LW19l64nm7Y" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>

[Muhr]

Sat at the computer a couple of nights ago and tried to make an excel sheet for an evaluation of transfertemp vs power that we are going to do in dyno. Do not think i got it right wondering if there's anyone who can correct below. Perhaps you who are injecting have knowledge about this
Added RSA values ​​as well as I know.
125 cc
Peake power rpm 13000
54hp crank
202 ° dur 56,767cc closed

Gas for this test
Octane (R + M) / 2 98
Research Octane 103
Motor Octane 93
Specific Gravity 0.762
Oxygen (weight%) 0
Leaded No.
BTU / Lb 18240
Btu / Gallon 115800 (cooling props)
Stoichiometric Air / Fuel Ratio 14.6

trapped volume121.4cc at 40 ° C mix and 40% Engine efficiency of trapped.!?:scratch::weep:

[Frits Overmars]

Try this Muhr.
Added RSA values ​​as well as I know.
125 cc
Peak power rpm 13000
54hp crank 54 hp at the gearbox exit shaft= about 57 hp at the crankshaft
202 ° dur 56,767cc closed 57,4 cc trapped stroke volume above the exhaust port + 8,6 cc combustion volume
Gas for this test
Octane (R + M) / 2 98
Research Octane 103
Motor Octane 93
Specific Gravity 0.762
Oxygen (weight%) 0
Leaded No.
BTU / Lb 18240
Btu / Gallon 115800 (cooling props)
Stoichiometric Air / Fuel Ratio 14.6 Lambda=0,85; actual air/fuel ratio=12,5
trapped volume121.4cc at 40 ° C mix and 40% Engine efficiency of trapped. Trapped volume=66 cc , 140% efficiency