ESE's works engine tuner

[Muhr]

'sad' news from Holland
RYGER seems to have big financial problems and will probably close down.


Sometimes things are a little too good to be true.

[breezy]

This announcement from the Dutch Chamber of Commerce would suggest that they are, Jan:I suppose it would also mean that you are no longer bound by your Non-Disclosure Agreement ;) .


Iim a bit saddened by this in some ways.... it gave us, at some point, a very extended topic on its make up..... as to non disclosure agreements being now void, it would certainly be interesting to have explained how they came about there claims and there design features which made them come to such conclusions. Also what caused it failure.......... Unless of course it was always a load of c--k and bo--u-ks.....if the receivers are now getting rid of there stock, maybe they will bang them out at discount prices, got to be worth a look at for less than 6500 euros...

[katinas]

Another interesting bathtub variation, head from tuned KTM SX 85.

[Haufen]

what do you think of this head from 2019 ktm250sx carburetor model ? they used this style in 2014 but i thought they went back to common bathtub design

I don't like it. Looks a bit as if sometime after 2011 the combustion chamber guy retired without passing his knowledge on to his successor. With a chamber like that, I suppose it would be possible to make an engine less aggressive at throttle pickup and where instant accelleration is needed. But this can be done by other means, and better, imo, e.g. running a filter in the ecu and / or ignition timing, carburetion and so on. Others do it this way. It's a bit like cutting a hole in your car ceiling because it's hot inside instead of just opening the window.

[wobbly]

Ha,ha, tuned KTM or Detuned KTM I would give it a 10% chance of doing anything good.
As for the Ryger picture a bit further back - I laughed like hell when I saw the complete engine like that.
The design genius just threw away 2 Hp by angling the carb down on the reed, but not a concern when you have 70 I suppose.
Reminded me of Jans/Frits old boss who did the same thing on his genius Chinese downward angled cylinder design.

[dutchpower]

:eek::spanking::spanking::spanking:
Another interesting bathtub variation, head from tuned KTM SX 85.

[husaberg]

It would be a bit difficult for KTM to go back to a common bathtub design, as they never did use a bathtub design in the first place.
Below left are a couple of KTM head designs, below right is a bathtub head, looking rather like a bathtub, wouldn't you say? :p
340971 340972

i know you are being cheeky I think when people often say bathtub in regards to 2 strokes they are referring to the cross section. Resembling an upside down bathtub.
If this is the case this case most would describe it as being it a more rounded version of the top hat shape of 60's.
340988340989
The pic should be familar:innocent:

[F5 Dave]

So, no coffee machines?


I don't drink the stuff but wife's birthday is coming up.

Take some bench space mind. . .

[F5 Dave]

Hopefully that Lucf or lucifer or whatever his handle was doesn't come back trying to explain that the Ryger was all good but shut down by the Israeli government or some such conspiracy.

Aliens. It was the aliens.


Disclosure; in the early days I was prepared to accept maybe there was some untried quantum step allowing silly revs and gas transfer but I couldn't understand it at all. Usually a sceptic but too dumb to form critical argument.
Fool me once.

[husaberg]

Hopefully that Lucf or lucifer or whatever his handle was doesn't come back trying to explain that the Ryger was all good but shut down by the Israeli government or some such conspiracy.

Aliens. It was the aliens.


Disclosure; in the early days I was prepared to accept maybe there was some untried quantum step allowing silly revs and gas transfer but I couldn't understand it at all. Usually a sceptic but too dumb to form critical argument.
Fool me once.

Frits wouldn't be as forthright or as rude as me, but i recal the first time i seen LucF name was when he started basically halfpie accusing Frits of copying his concept with the FOS.
My favour Lucism was the one when he told me after i had released the patent with the inventors name on it,That i must delete the post and that he had already contacted me beforehand and i had agreed not to release Gerrits Name
Which was total horseshit.
My pick is if he doesnt blame the Shape shifting lizard-men it might be the petrol companies ie BIG OIL trying to keep them out of business or maybe Some bike manufacturer.

[jamathi]

Frits wouldn't be as forthright or as rude as me, but i recal the first time i seen LucF name was when he started basically halfpie accusing Frits of copying his concept with the FOS.
My favour Lucism was the one when he told me after i had released the patent with the inventors name on it,That i must delete the post and that he had already contacted me beforehand and i had agreed not to release Gerrits Name
Which was total horseshit.
My pick is if he doesnt blame the Shape shifting lizard-men it might be the petrol companies ie BIG OIL trying to keep them out of business or maybe Some bike manufacturer.

Honda for sure is scared shitless by the RYGER patent.....
So they kindly arranged for it's bankruptcy!!!
Mr. Hendrik Gerrits is VERY scared of a photo of him being published.
I have one....
Why would that be?
Someone looking for him?
Someone who's money he stole, he has been condemned for such things in the past....
And served some time in jail!!

[husaberg]

Honda for sure is scared shitless by the RYGER patent.....
So they kindly arranged for it's bankruptcy!!!
Mr. Hendrik Gerrits is VERY scared of a photo of him being published.
I have one....
Why would that be?
Someone looking for him?

Honda should be scared they struggled to get anywhere near 50HP out of a 125.:msn-wink:
Even with a friendly Dyno and millions of dollars of R&D.
Silly thing with Ryger if they they were honest without the stupid hype they might have actually had an acceptable level of performance with lower potential emissions.

I remember in the late 1990's honda openly wanted to lower the cc's of the 500 class to 375 or something i could never figure out why
Do you have any ideas it was kind of playing into Aprilias hand dropping the open class size.

[Sandokan]

A couple of years back i had a (now moved) neighbour that was a financier for the ryger project.
During a street bbq he told me lots of details going on during development.
At that time he also told me that they where having trouble with the piston.
I had a private chat with a common friend of jan and me where we sometimes exchanged ideas about his zundapp with verry powerfull output. I also told him what i heared about ryger.
This information ended up at jan who shared it with the world as he likes to share his knowledge we are so thankfull for.

It kind of got me in a position where i didnt want to be. Harrie contacted me and so did my loaded neighbour.
And i felt bad for it fore a while. As a romantic enthousiast i always hoped they would succeed. First of all for the saviour of the two stroke and for the proudness of also beeing dutch. If thats worth annything.

I never signed disclosure.

[katinas]

Interesting thing, on Katoh NSR 250 2001 engine, the cylinders little angled, about 10 degrees, to let mix flow in symertrical way, from carb/reed to crankcase, as no space for symetrical location to both carbs on this configuration with two cranks. Piston pin hole from one side must been pluged, as too much area open for shortcut between wide Ex and A trans windows, or maybe special piston just with one side pin hole.

[F5 Dave]

A couple of years back i had a (now moved) neighbour that was a financier for the ryger project.
During a street bbq he told me lots of details going on during development.
At that time he also told me that they where having trouble with the piston.
I had a private chat with a common friend of jan and me where we sometimes exchanged ideas about his zundapp with verry powerfull output. I also told him what i heared about ryger.
This information ended up at jan who shared it with the world as he likes to share his knowledge we are so thankfull for.

It kind of got me in a position where i didnt want to be. Harrie contacted me and so did my loaded neighbour.
And i felt bad for it fore a while. As a romantic enthousiast i always hoped they would succeed. First of all for the saviour of the two stroke and for the proudness of also beeing dutch. If thats worth annything.

I never signed disclosure.
Well you had the Microscope not that long back and now you want something else? That's just greedy.

[katinas]

A couple of years back i had a (now moved) neighbour that was a financier for the ryger project.
During a street bbq he told me lots of details going on during development.
At that time he also told me that they where having trouble with the piston.
I had a private chat with a common friend of jan and me where we sometimes exchanged ideas about his zundapp with verry powerfull output. I also told him what i heared about ryger.
This information ended up at jan who shared it with the world as he likes to share his knowledge we are so thankfull for.

It kind of got me in a position where i didnt want to be. Harrie contacted me and so did my loaded neighbour.
And i felt bad for it fore a while. As a romantic enthousiast i always hoped they would succeed. First of all for the saviour of the two stroke and for the proudness of also beeing dutch. If thats worth annything.

I never signed disclosure.

Thanks, your words returned some memories from testing with rygerised NS/CR barrels and now very funny to found my own mistakes everywhere that really must do influence on engine performance. Maybe needed to write some words. ( Add pic, with another mistakes on piston that was not tested and plate that designed to do things without assistance from under piston pressure at BDC just direct flow from carb to trans).
Remember one video from short testing on straight, with really nice engine sound, but maybe this was not just separation plate with normal scavenging like showed in homologation papers.

Not in theme, but when my kids switch on to war mode, and then I tried show them peace flag, I always left guilted.

[katinas]

I remember in the late 1990's honda openly wanted to lower the cc's of the 500 class to 375 or something i could never figure out why
Do you have any ideas it was kind of playing into Aprilias hand dropping the open class size.

Looks like this was consideration between three cylinders 375 and two cylinders 500 for private teams, but 500 V2 wins. Interesting, on V2 prototype they even tested 17.5 inch front wheel to solve some problems with front and engine with firing on both cylinders at the same time with crank pins offset 100 degrees, like between the cylinders. But normal production racing version had firing between cylinders about 78 degrees with crank pins offset 22 on 100 degrees V2 engine.

[Sandokan]

Well you had the Microscope not that long back and now you want something else? That's just greedy.
Im not sure what you mean by this dave?

[jbiplane]

http://www.reaa.ru/yabbfiles/Attachments/IMG-20190221-WA0005.jpg
Implementing... Hope test soon

[Michael Moore]

below right is a bathtub head, looking rather like a bathtub, wouldn't you say? :p
340972

FWIW, back in the day that Bultaco combustion chamber design was often called a "trench head" here in the USA.

cheers,
Michael

[F5 Dave]

Im not sure what you mean by this dave?
Just an attempt at humour, but if one has to explain it then I guess it was a bad attempt. I'll try harder next time.

[Sandokan]

Just an attempt at humour, but if one has to explain it then I guess it was a bad attempt. I'll try harder next time.

😂 well dave im glad. Realy thought i offended you.

[katinas]

Implementing... Hope test soon


Good to see your work and trying to save some pumping volume with smaller lower piston construction.

Worst thing with my engine was zero torque at mid rpm. In my case with upper 57mm and lower 38mm and 50.6mm stroke, pumping capacity lowered from 129cc to 71,7cc, and this reduced pumping volume, maybe do big influence on very low performance at mid rpm.

With stepped piston, tested two different cylinders, one from Honda NS 400 other from CR125, but both with normal scavening,
Whatever I try with different modifications on both cylinders, one thing was always the same - zero torque from, aproxx 3500 to 7000 rpm, . All additional variations helps boost power just in pipe working zone aprox from 8000 to 12000rpm.

Driving from 0 to 3500 rpm was acceptable and not changed from normal engine, can ride uphill easy, but just until 3500 rpm. Then, when I wanted to jump over ZERO torque zone rpm to 7000 level, I must operated with gas in the way that I never try all my life before. It took about 30 seconds in first gear (street ratio) when revs slowly rise up to 7000rpm, then all goes in normal way. It feels very similar to normal engine without one reed leap take off. Maybe much thicker reeds leaps would help.
When main central intake window was blocked on CR cylinder, power suddenly rise up at pipe working range. Big difference, remember was bests from all previous tests, but side lower windows between crankcase and transfers channels still left opened. This is where tests was ended, because when I put new ring for new test ,simply forget to adjust piston ring gap, and very soon piston was destroyed.
Another thing is very short 92 mm conrod (original 109 mm). This changed piston and flow dynamic. Piston acceleration higher through 90-TDC-270 ( pressure changed faster under the piston and compression too) and slower from 270-BDC-90 ( slower pressure build up under the piston, lower velocity through transfers, longer opened trans windows with the same cylinder in comparison with 109 mm std). Maybe not very accurate comparison, but with the same stroke its like opposite to four stroker intake . With short conrod on four stroke, intake flow dynamic is like on two stroke with long conrod.
With stepped piston there is no needed thrust on main piston skirt, so this let to do shorter main piston skirt all around where transfers windows are located and this appears possibilities switch on transfers windows in suction mode, when piston moves up and skirt opens transfers windows. This let mix flow from carb, directly to transfers if there is connecting channels between them.
On normal engine with special piston, this mix traveling way, can do work alone, without any pressure assistance, from the moment, when piston skirt side edges closes transfers windows on down stroke and until opens again when piston moves up. At this period, pressure under piston, works just like spring, as no any way to go out, as space is isolated. On this configuration, carburetor communicate with crankcase, only when piston side skirt open transfer windows. Surprisingly it works, power no worse than with normal scavening, even just with only Boyesen channels for intake, as main center intake window was blocked to arranged all flow directly to transfer channels. But this was not tried with stepped piston.
Interesting thing, that is not work, is compressor mode, when tried under piston squash at BDC with CR cylinder test. It take too much pumping looses and with bigger gap engine work better.
Best thing would be to minimize all pumping looses as much as possible and at the same time keeping flow through engine.

[jbiplane]

Best thing would be to minimize all pumping looses as much as possible and at the same time keeping flow through engine.
Hi Katinas, thanks for so detailed description of your experience. According CAD model I have "crancase" volume changing from 499 to 222сс.
The base engine is snowmobile 2-cylinder inline RMZ550 76x61mm.
Will see how it will work. For me important to have good power on high rpm, cause this engine will drive propeller (brake load depend of rpm in cube).

The next iteration should be something like this
https://www.youtube.com/watch?v=tccPMi29tvc

[Tim Ey]

Hi jibplane,

you re-invented the "Kurbelschlaufenmotor" from Ficht. But on the Ficht engine, the Conrod is cylindric with a seal to divide crankcase and pre compression chamber. Also the piston can be produced on a lathe since it is screwed to the rod through the piston crown with a sunk in screw.
Benefit: Pumping likewise regular twostroke engine, very good sealing from crank to cylinder, lower conrod bearing can be pressure fed, no upper conrod bearing, no mass forces 1+2 order, no lateral forces on the piston, 2stroke oil only required to lube the piston, no piston pin.
Downsides: The "Kurbelschlaufe" that sits on the big end is quite a hassle and everything needs to be exactly parallel and perpenticular.

If you get this done as a 4cylinder boxer engine with your injection system, you may either build a 4-2-1 pipe or a 4-2 pipe.

[Michael Moore]

https://de.wikipedia.org/wiki/Kurbelschlaufenmotor

That looks like a Scotch Yoke at the crank, I thought it would need something like that. Those usually seem to be limited to slower-speeds, I've seen them used in large sheet metal nibblers/trimmers. But aero engines often seem to run at fairly low speeds, I presume to reduce the need for a propellor speed reduction drive.

cheers,
Michael

[peewee]

what was the theory of how ryger would have so much power ?

jbiplane: if i understand it sounds like good crankcase pumping is important at middle rpm but at high rpm when pipe is working then the crankcase is not so important ?

[Frits Overmars]

Hi jibplane, you re-invented the "Kurbelschlaufenmotor" from Ficht.
https://de.wikipedia.org/wiki/Kurbelschlaufenmotor
That looks like a Scotch Yoke at the crank, I thought it would need something like that. Those usually seem to be limited to slower-speeds.Michael, you're quite right about the Kurbelschlaufenmotor using a Scotch Yoke and about it's sliding movement rendering it unfit for high rpm values.
But the video posted by Jbiplane did not show a Scotch Yoke crank, but an epicycloid crank, with no sliding movement involved, and much better suited for high revs.
341021 341020

Neil Hintz, aka Flettner (who else?) already showed his version some time ago.
341022 341023 341024

[husaberg]

Michael, you're quite right about the Kurbelschlaufenmotor using a Scotch Yoke and about it's sliding movement rendering it unfit for high rpm values.
But the video posted by Jbiplane did not show a Scotch Yoke crank, but an epicycloid crank, with no sliding movement involved, and much better suited for high revs.
341021 341020

Neil Hintz, aka Flettner (who else?) already showed his version some time ago.
341022 341023 341024

https://hips.hearstapps.com/hmg-prod.s3.amazonaws.com/images/rotary-1545852112.gif

[Frits Overmars]

Yes Husa, we should forget about reciprocating rods and pistons altogether.
The Wankel was a brilliant idea, if only it wouldn't have such a lousy combustion chamber shape and ditto surface area to volume ratio.
What's next? Electromotors, that's for sure. But how are we going to feed them and achieve some decent mileage?
My hopes are pinned on fuel cells; not the original hydrogen-processing kind, but the kind that will accept liquid hydrocarbons like petrol or methanol.

[Haufen]

Yes Husa, we should forget about reciprocating rods and pistons altogether.
The Wankel was a brilliant idea, if only it wouldn't have such a lousy combustion chamber shape and ditto surface area to volume ratio.
What's next? Electromotors, that's for sure. But how are we going to feed them and achieve some decent mileage?
My hopes are pinned on fuel cells; not the original hydrogen-processing kind, but the kind that will accept liquid hydrocarbons like petrol or methanol.

Or you can just run your two-stroke on carbon neutral fuels (https://en.wikipedia.org/wiki/Carbon-neutral_fuel). Saves the fuel cell, no need for an electric motor either, and comes with that beautiful sound already out of the box! :drinknsin

[Haufen]

Carbon neutral; there is just one word for it: bullshit.
Burning a carbon neutral fuel, for example bio-ethanol, produces exactly the same amount of CO2 as burning conventional ethanol. You cannot even distinguish between the two fuels in the most sophisticated laboratory. And neither can the trees; they will absorb 'conventional' CO2 just as well as bio-CO2.
Biofuel comes from crop that used atmospheric CO2 for its growth. And were do fossile fuels come from? From crop that grew some time ago; what's the difference?
The politicians who keep saying that biofuel do not contribute to the CO2 in the atmosphere, must think that we're all retarded...

You might want to read into this a bit more before putting it into the bullshit corner.
I was talking about carbon neutral fuels, not biofuels. Carbon neutral fuels take CO2 out of the atmosphere during production (https://news.nationalgeographic.com/2018/06/carbon-engineering-liquid-fuel-carbon-capture-neutral-science/), which is later re-released into it by being burned in e.g. internal combustion engines.

[jbiplane]

you re-invented the "Kurbelschlaufenmotor" from Ficht.
No its simplified version of Parson-Balandin engine. I believe simplification makes stuff better.



jbiplane: if i understand it sounds like good crankcase pumping is important at middle rpm but at high rpm when pipe is working then the crankcase is not so important ?
I want create test inline 2-cylinder engine and educate its behavior.



But the video posted by Jbiplane did not show a Scotch Yoke crank, but an epicycloid crank, with no sliding movement involved, and much better suited for high revs.
Exactly. I want avoud use gears, just essentrics. Saw Japan patent for compressor like this.

A question, Anyone have experience with intake valve without petals like on this picture?
http://www.reaa.ru/yabbfiles/Attachments/RIV_Valve.jpg

[lohring]

Yes Husa, we should forget about reciprocating rods and pistons altogether.
The Wankel was a brilliant idea, if only it wouldn't have such a lousy combustion chamber shape and ditto surface area to volume ratio.
What's next? Electromotors, that's for sure. But how are we going to feed them and achieve some decent mileage?
My hopes are pinned on fuel cells; not the original hydrogen-processing kind, but the kind that will accept liquid hydrocarbons like petrol or methanol.

So far cost is the issue of fuel cells versus batteries. We are barely getting battery costs low enough to make electric vehicles competitive in price with luxury IC cars. So far fuel cells look good for larger vehicles. We'll see what happens with trucks. Of course batteries require a clean electric generating system. That's easier to do on a large scale than in a car size plant. Quite a few people are using solar cells with batteries to generate power for their houses and cars. That works best in the US southwest and is more expensive than conventional power generation so far.

Lohring Miller

[jasonu]

Frits wouldn't be as forthright or as rude as me, but i recal the first time i seen LucF name was when he started basically halfpie accusing Frits of copying his concept with the FOS.
My favour Lucism was the one when he told me after i had released the patent with the inventors name on it,That i must delete the post and that he had already contacted me beforehand and i had agreed not to release Gerrits Name
Which was total horseshit.
My pick is if he doesnt blame the Shape shifting lizard-men it might be the petrol companies ie BIG OIL trying to keep them out of business or maybe Some bike manufacturer.

I'm totally surprised you are not blaming Donald Trump for their demise...

[Niels Abildgaard]

Hi Katinas, thanks for so detailed description of your experience. According CAD model I have "crancase" volume changing from 499 to 222сс.
The base engine is snowmobile 2-cylinder inline RMZ550 76x61mm.
Will see how it will work. For me important to have good power on high rpm, cause this engine will drive propeller (brake load depend of rpm in cube).

The next iteration should be something like this
https://www.youtube.com/watch?v=tccPMi29tvc

This looks like

http://www.douglas-self.com/MUSEUM/POWER/unusualICeng/RotaryValveIC/RotaryValveIC.htm#esscross

If You make thepiston connectors round there can be a stuffing box round each (like crosshead engines)

[husaberg]

Yes Husa, we should forget about reciprocating rods and pistons altogether.
The Wankel was a brilliant idea, if only it wouldn't have such a lousy combustion chamber shape and ditto surface area to volume ratio.
What's next? Electromotors, that's for sure. But how are we going to feed them and achieve some decent mileage?
My hopes are pinned on fuel cells; not the original hydrogen-processing kind, but the kind that will accept liquid hydrocarbons like petrol or methanol.

True but i was pointing out the geared crank, The Wankel does have issues with the combustion shape but its perfect for forced induction also it capable of burning Hydrogen raw as its cumbustion is carried out in a seperate place than its induction and compression.
Personally i dont see electricity as being an answer
Why think of a plane it takes of with a larger load of fuel but the further it flys the lighter the fuel load gets which allows a greater range.
It it was electric it would weigh the same at take off as landing. a real great self sustaining fuel cell might work but i cant see that happening
The USA experimented with Nuclear planes in the 50's but gave up.
here is the old test reactors for them.
https://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Aircraft_Reactors_Arco_ID_2009.jpg/1280px-Aircraft_Reactors_Arco_ID_2009.jpg
They even built a nuclear ramjet using the heat from the reactors to power the plane.
Not sure why they never thought off powering the props direct.
That said NASA now have some tiny tiny reactors.
https://i.kinja-img.com/gawker-media/image/upload/s--tzkmYTxL--/c_scale,f_auto,fl_progressive,q_80,w_800/ijetlydyg4ywsbmymzlh.jpg
15cm chunk of uranium-235 lasts 10 years at 10KW.

[Niels Abildgaard]

I did

By the way my present home town Dresden


Work or pleassure?

[Frits Overmars]

Work is pleasure if you do it right Niels :D

[Grumph]

A question, Anyone have experience with intake valve without petals like on this picture?
http://www.reaa.ru/yabbfiles/Attachments/RIV_Valve.jpg

That's cunning. Does it actually work or is it just a concept ?

Given the tuning fork likeness, you'd think it was a natural for Yamaha...

[andreas]

Would not this type of reed offer less turbulance and resistance?

[Frits Overmars]

Would not this type of reed offer less turbulance and resistance?It might, if it could be opened by some mechanism. But if it must be opened by air pressure, as is customary for reed valves, the problem is that there is hardly any surface at the reed tips for this pressure to act upon.

[andreas]

Yes, I was thinking the petals maybe look like this or be of varying thickness.

[husaberg]

Yes, I was thinking the petals maybe look like this or be of varying thickness.

Why not have them hinged.
https://ae01.alicdn.com/kf/HTB1pHYOJpXXXXcbXXXXq6xXFXXX1/1-inch-spring-hinge-Small-spring-hinges-with-spring-hinges-nickel-plated.jpg_640x640.jpg
They could also be opened and closed electromagnetically.
https://cdn4.explainthatstuff.com/how-relay-works2.gif

[TZ350]

They could also be opened and closed electromagnetically.


If we are going to open/close things electromagnetically why not do away with the rotary valve and adapt push pull voice coil servos to Flettners flying gib idea and have totally asymmetric and variable inlet timing and when the engine is truly on the boil. Hold them both open for Frits's 24-7 timing.

:sunny: 341040 341041 341042

[husaberg]

If we are going to open/close things electromagnetically why not do away with the rotary valve and adapt push pull voice coil servos to Flettners flying gib idea and have totally asymmetric and variable inlet timing and when the engine is truly on the boil. Hold them both open for Frits's 24-7 timing.

:sunny: 341040 341041 341042

The idea was to use it only at low speed for starting. then as you say 24/7
I think Flets gib is great but i am not sure it could be moved fast enough to serve as a starting valve.
It would be great if i was wrong and it could be though.

[TZ350]

I think Flets gib is great but i am not sure it could be moved fast enough to serve as a starting valve.

Sure, maybe not as it is but a twin guillotine thing might. A voice coil arrangement each end shuttling the guillotines back and forth. 12,000rpm is only 200 Hz. 20 to 200 Hz is the audio sub woofer range. 200Hz is not very fast for electrotrickery.


341050


https://www.sae.org/publications/technical-papers/content/2017-01-1070/

2017-03-28Research on a New Electromagnetic Valve Actuator Based on Voice Coil Motor for Automobile Engines 2017-01-1070


The electromagnetic valve actuator (EMVA) is considered a technological solution for decoupling between crankshaft and camshaft to improve engine performance, emissions, and fuel efficiency. Conventional EMVA consists of two electromagnets, an armature, and two springs has been proved to have the drawbacks of fixed lift, impact noise, complex control method and large power consumption. This paper proposes a new type of EMVA that uses voice coil motor (VCM) as electromagnetic valve actuator. This new camless valvetrain (VEMA) is characterized by simple structure, flexible controllable and low actuating power. VCM provides an almost flat force versus stroke curve that is very useful for high precision trajectory control to achieve soft landing within simple control algorithm. The halbach magnet array and coil structure are specially optimized to provide flux-focused interleaved magnetic circuits for maximizing the actuating force. 2D and 3D magnetic simulation is applied to analyze the performance of VEMA. A cascade feedback with velocity and acceleration feedforward control structure is developed. Two cascade PID feedback controllers are used to realize the position and current loop and the feedforward controller is applied to enhance the trajectory tracking performance by utilizing the information from the repeated precognition reference trajectory. Simulated and experimental results indicate that the proposed VEMA and the control methodology are capable of achieving fully flexible valve motion with low seating velocity and power consumption.

[Frits Overmars]

If we are going to open/close things electromagnetically why not do away with the rotary valve and adapt push pull voice coil servos to Flettners flying gib idea and have totally asymmetric and variable inlet timing and when the engine is truly on the boil. Hold them both open for Frits's 24-7 timing. The simplest solution for totally asymmetric and variable inlet timing is the common reed valve; it doesn't need any governing. It won't flow as well as a rotary valve,
but below the power band that doesn't matter. And once we're in the power band we can hold it open 24/7 as you say. A simple servo motor can do that; we can even use the exhaust power valve servo if there is one.
No need for any electromagnets. I doubt if those could be fast enough for cycle-to-cycle operation anyway. It's not like lifting an injector needle 0,1 mm off its seat;
a reed valve should move about a hundred times further, but at the same frequency as that injector needle....

[husaberg]

The simplest solution for totally asymmetric and variable inlet timing is the common reed valve; it doesn't need any governing. It won't flow as well as a rotary valve,
but below the power band that doesn't matter. And once we're in the power band we can hold it open 24/7 as you say. A simple servo motor can do that; we can even use the exhaust power valve servo if there is one.
No need for any electromagnets. I doubt if those could be fast enough for cycle-to-cycle operation anyway. It's not like lifting an injector needle 0,1 mm off its seat;
a reed valve should move about a hundred times further, but at the same frequency as that injector needle....

My original musing Frits was to you the electromagnet to keep it open. Once it was going well allowing the 24/7. Not really well written though by me though. As i did say open and shut.

[TZ350]

The simplest solution for totally asymmetric and variable inlet timing is the common reed valve; it doesn't need any governing. It won't flow as well as a rotary valve, but below the power band that doesn't matter. And once we're in the power band we can hold it open 24/7 as you say. A simple servo motor can do that; we can even use the exhaust power valve servo if there is one.

True, complex is easy but hard to do better than the simplicity of a reed and actuator to hold it open for 24/7 ......

[TZ350]

My original musing Frits was an electromagnet to keep it open.

I agree, that could be done very easily with a spring steel reed and an electro magnet in the roof of the reed cage to grab and hold the reed open when the inlet resonance is in the right place for 24/7.

[husaberg]

I agree, that could be done very easily with a spring steel reed and an electro magnet in the roof of the reed cage to grab and hold the reed open when the inlet resonance is in the right place for 24/7.

I also think you could also impregnate the glassfibe or Carbonfibre reed with a strip of iron. it only needs the very end to be be magnetically attractive

<iframe src="https://giphy.com/embed/5YucDCanSXVPFol3DJ" width="480" height="270" frameBorder="0" class="giphy-embed" allowFullScreen></iframe><p><a href="https://giphy.com/gifs/blow-up-epic-5YucDCanSXVPFol3DJ"></a></p>
<iframe src="//gifs.com/embed/screaming-jimmy-16cyl-2-stroke-detroit-diesel-16v71-wide-open-fullsend-mOw5q0?muted=false" frameborder="0" scrolling="no" width="640px" height="360px" style="-webkit-backface-visibility: hidden;-webkit-transform: scale(1);"></iframe>

[katinas]

The base engine is snowmobile 2-cylinder inline RMZ550 76x61mm.
Will see how it will work. For me important to have good power on high rpm, cause this engine will drive propeller (brake load depend of rpm in cube).


With 76mm x 61mm and rod (from your previous pic, add, looks like 25mm smaller dia /46mm bigger dia), pumping volume reduction is just 30cc, so from 276cc to 246cc it would be minimal influence.
Its similar to Rotax 503 engine.

Another important thing, is that on two stroke, crankcase and crank is very close and this space not adapted to work just with oil, too much drag. I remember when filling just about 15 ml oil, engine didnt revs until some oil was pumped through left side open crank bearing ( mistake again because of some drag) to side empty crankcase space. Interesting how much energy wasted for this, when engine revs high. Maybe crankcase must be modified in some ways to work with oil.
Another mistake in my configuration, is that crankcase work with negative pressure. Reeds in crankcase (if they used), must be oriented to hold positive pressure, not negative.
Positive pressure help to prevent some fuel leakage through smaller piston seal to crankcase , little help to stop piston at BDC and oil work in pressurised, not stretched environment

[TZ350]

I also think you could also impregnate the glassfibe or Carbonfibre reed with a strip of iron. it only needs the very end to be be magnetically attractive

True and probably would work but no need, because we are looking to 24/7 for power so any old steel reed will do to get us into the zone before holding the reed open 24/7.

[andreas]

[QUOTE=husaberg;1131126268]Why not have them hinged.
https://ae01.alicdn.com/kf/HTB1pHYOJpXXXXcbXXXXq6xXFXXX1/1-inch-spring-hinge-Small-spring-hinges-with-spring-hinges-nickel-plated.jpg_640x640.jpg
They could also be opened and closed electromagnetically.
https://cdn4.explainthatstuff.com/how-relay-works2.gif[/QUOT

Ok, but no chickens.

[husaberg]

That's cunning. Does it actually work or is it just a concept ?

Given the tuning fork likeness, you'd think it was a natural for Yamaha...

I never noticed that, Looks a heck of a lot like a tesla valve

[jbiplane]

Maybe crankcase must be modified in some ways to work with oil.
Thanks for valuable comments. Going to instal pressure sensors in few places and understand how everything works.

You are correct the diameters are 25 and 46mm, next time will make a bit smaller part.

[Haufen]

I did read a bit more into it:That sounds great if you have an energy source like hydro or solar power. But what if you don't? Then the 'lot of electricity' has to come from fossile fuels. Or biofuels :p

By the way, carbon-neutral liquid fuel (fuel from electricity) as well as fuel cell (electricity from fuel) research are being performend in my present home town Dresden
by a company called Sunfire, of which my former partner in the Dresden Technical University is a staff member, so the concept wasn't entirely new to me.

So help me out here: if you were familiar with the concept, why do you call it bullshit? Did you tell your former co-worker that it's bullshit, too? What did he respond?
What would be the range benefit of the fuel cell stack researched in Dresden (SO type?) compared to current hydrogen stacks when sized for vehicle applications?

And by the way, I may be a bit closer to both fuel cell technology as well as synthetic fuels than just happening to live in the same city or having a former co-worker being a staff member. And in this surrounding, there is no mileage problem with hydrogen fuel cell vehicles (although the gas station network could be narrower), the research on hydrocarbon fed fuel cells for vehicles has been shelved a decade ago or so (but seems to do ok with power plants), synthetic carbon neutral fuels are regarded as a realistic means to meet upcoming CO2 targets (in combination with other technologies, but compared to new technologies they'd have an effect on the already existing vehicle fleet, too!). And surely nobody would use fossil fuel to generate electricity to then generate synthetic fuel (except for research purposes). If there were no green energy source available that electricity would come from nuclear power plants, I suppose (did not say I like them or the idea). Also, overcapacities in the power grid might be used much more efficiently than they are now when utilised to make synthetic fuels.



So far cost is the issue of fuel cells versus batteries. We are barely getting battery costs low enough to make electric vehicles competitive in price with luxury IC cars. So far fuel cells look good for larger vehicles. We'll see what happens with trucks. Of course batteries require a clean electric generating system. That's easier to do on a large scale than in a car size plant. Quite a few people are using solar cells with batteries to generate power for their houses and cars. That works best in the US southwest and is more expensive than conventional power generation so far.

Lohring Miller

US based Nikola Motor Company plans on starting series production for hydrogen fuel cell trucks as early as 2020 ( https://nikolamotor.com/one )

[Frits Overmars]

So help me out here: if you were familiar with the concept, why do you call it bullshit?You're right Haufen. I'd never call any form of research bullshit. My frustrated reaction was mainly triggered by the way politicians and marketing people keep suggesting that CO2 coming from once cource differs from the same gas coming from another source, when it suits their purposes ("this fuel does not add CO2 to the atmosphere")
and the way they keep mixing the concepts of energy sources and energy carriers for the same reason.

[husaberg]

You're right Haufen. I'd never call any form of research bullshit. My frustrated reaction was mainly triggered by the way politicians and marketing people keep suggesting that CO2 coming from once cource differs from the same gas coming from another source, when it suits their purposes ("this fuel does not add CO2 to the atmosphere")
and the way they keep mixing the concepts of ernergy sources and energy carriers for the same reason.

The largest retailer in NZ just declared themselves carbon neutral.
I was think wow how did they do that being a retailers of mainly plastic junk aChinefrom.
Turns out they only include it from when they leave China and not the manufacturing or and they also are buying carbon credits cheap off others, they are also pledging to plant 2 million trees.
WE got screwed with all the carbon credit stuff as they dont include pasture or native forests. only trees planted after 1985 or something.
https://webcache.googleusercontent.com/search?q=cache:V4ok-OsIfLYJ:https://www.msn.com/en-nz/money/news/warehouses-carbon-neutral-status-just-creative-accounting-critic/ar-BBTE6CN+&cd=1&hl=en&ct=clnk&gl=nz

[Sandokan]

I think the whole CO2 hype is just a way to make us pay.
They found in ice cores tens of thousand years old that there is a cycle in CO2 variation.
It follows the solar cycle and it is seperated by 800 years.
The cycle is arround 12000 years and when the sun is at its "high" point then 800 years later the CO2 rises. The heating from the ocean takes a while and naturaly releases more CO2
All this has occured milions of years in the past where they measured way more CO2 that was present than during the présence of man or industry for that matter.

What Gore did was move the graphics so that the CO2 lined up with temperature:nono:

Breatheable air i have no doubt can be of bad quality but CO2 wont kill me at these predicted levels.

I want to ask if someone knows where to see the evidence of crude oil beeing off fossil origin.
I have been searching for many years but to this day not able to find it.

Sander

[TZ350]

341110341111341109

Blue line is the pressure trace from the simulator and the yellow dots are indicators of when the readings are being taken by the pseudo MAP co processor. The oscilloscope screen shows 12,000 RPM, so speed and accuracy are good.

High/Low difference 3411121.50 @ 65% TP 341113 1.00 @ 15% TP 341114 0.75 @ 5% TP all at 12,000rpm.

It has proven to be a bit of a long road to being able to test out the crankcase pressure (Max-Min)*3 = MAP concept. Hopefully I am getting close. The first cut of the pseudo MAP co processor was a bit of a failure. So I got hold of an oscilloscope and developed a two stroke crankcase pressure simulator with another Arduino Nano. Took two weeks as progress was a bit slow but auntie Google helped a lot with how to go about C++ coding, timing and interrupts.

The simulator puts out a signal sweep from 500 rpm to 14,000. Signal out is an ignition pulse and high/low pressure trace. The big trick was to keep the pressure trace proportional time wise between ignition pulses so that the peak always happened at 135 ATDC and a low at 315. The pseudo MAP co processor is triggered each cycle from the ignition pulse then has to accurately find the 135 and 315 crank angle positions before reading the crankcase pressure sensor and translating that into a MAP reading for the EFI's CPU.

All this to find out if the crankcase pressure (Max-Min)*3 = MAP concept could be a reliable/usable indication of airflow through a two stroke motor that runs higher than 10,000 RPM and makes better than 10bar BMEP. Ie., a 2S motor that is very dependent on its pipe for performance. Ride ability is the problem. Higher than 10/10 and fueling suffers from un-predictable changes in air flow as pipe resonance collapses on small throttle openings.

10/10 seems to be the ride able cross over point. Anything under 10/10 can be fueled using the Alpha-n topology as air flow is reasonably consistent. But over 10/10 air flow becomes increasingly variable depending on the resonance action of the pipe. Over 10/10 some way of seeing changes in air flow are needed. Something like the 4S MAP concept. The EFI KTM lives below the 10/10 performance barrier. Making big power and rpm with EFI is easy but getting big power and high rpm and ride-ability coming back onto the throttle is the issue over 10/10. I am trying to do better and push past into the 10/10 performance death zone and still have a ride-able bike.

[Michael Moore]

The EFI KTM lives below the 10/10 performance barrier.

Very impressive, I look forward to you being able to utilize this new developmen to solve the problems you are having.

I only have one carburetor to my name, a new/unused 38 PWK I purchased for the 2015 KTM 250SX track day project. EFI sounds appealing for my KTM as I'd rather keep my hands clean while screwing up the jetting with a lap top vs screwing it up by changing jets with fuel spilling on a hot engine. But that would depend on being likely to get the engine to run acceptably with EFI. I could buy the OEM TPI ECU/parts but about 5% of those bikes seem to have weird running issues. The Athena/GET replacement ECU for the TPI model sounds like it runs well and is readily available, and there's a plethora of capable aftermarket ECUs if I wanted to try and roll my own conversion.

10 bar is 145 PSI. My copy of Bell's book indicates that a 50hp 250MX (like my KTM 250SX with a Pro Circuit 2 extended power at higher RPM pipe) seems like it should probably be around 120-125 psi (8.5-9 bar), and since it would be a track day engine I don't see any need to exceed 9500 RPM. Does it seem likely that the 250SX would be sufficiently below the critical point to be able to run with Alpha-N if I had to go that way?

From a magazine test of the KTM 250SX PC2 pipe as an example of the expected performance level:


the stock pipe delivers incredible midrange but falls off quickly after its peak at 8200 rpm where it was making 47.30 horsepower. With the Pro Circuit Works pipe installed, peak is moved to 49.60 horsepower at 8300 rpm. That is a 2.2-horsepower gain at peak, but most important, the pipe didn’t fall off as quickly after peak as the stocker. The Pro Circuit pipe made the same power as the stock pipe from 5000 rpm all the way to 7200, then the Pro Circuit pipe made 1 horse more at 7500 rpm, 1.6 more at 8000 rpm and 4 horses more at 9000 rpm.

cheers,
Michael

[TZ350]

10 bar is 145 PSI. My copy of Bell's book indicates that a 50hp 250MX (like my KTM 250SX with a Pro Circuit 2 extended power at higher RPM pipe) seems like it should probably be around 120-125 psi (8.5-9 bar), and since it would be a track day engine I don't see any need to exceed 9500 RPM.

Does it seem likely that the 250SX would be sufficiently below the critical point to be able to run with Alpha-N if I had to go that way?

Yes I think so. But it is dependent on the pipe. The more the pipe shifts air when its working, ie higher performance the less likely the Alpha-N fueling topology will be suitable.

Flettner has a 50hp Kawasaki Big horn running E85 and his friend Wayne has a Yamaha YZ250 on petrol. Both running EFI Alpha-N fuel control mapping and I think both run near to 9,000rpm. I expect E85 or a methanol/mix if allowed would be a great help for fueling.

BigHorn <cite class="iUh30" style="color: rgb(0, 102, 33); font-style: normal; font-size: 14px; padding-top: 1px;">https://www.youtube.com/watch?v=eleqBGvOM4M</cite>
(https://www.youtube.com/watch?v=eleqBGvOM4M)
First start of the Yamaha YZ250 https://youtu.be/hOGZ5llowoU

The issue with greater than 10 bar BMEP is that when you close the throttle the wave action in the pipe collapses and there is a drastic change in air/fuel ratio, Alpha-N can't cope with that. less tuned bikes can get away with it.

Above 10,000 RPM you need staged injection, a small injector for tune ability and a big one to get the job done above 10k in the diminishing amount of time available. Both injectors deliver about the same amount of fuel per revolution but above 10k rpm you need something big to get it in there quickly.

KTM have only two injectors, one in each "B" port. at low speed they fire them alternately and above a certain point they fire them together. That is a very clever way of getting staged injection. Although you may not have fired an injector on that side there is always some vaporized fuel present from the last injection cycle.

From my experience a 2S motor does not seem to care much if there is an imbalance in delivery so long as the sum of the air/fuel trapped in the cylinder is correct and mixed properly. An alternating imbalance is Ok but the motor will kick up a fuss after a few revolutions if there is no fuel at all coming from one side. Probably inconsistent mixing in the cylinder.

Making power and tune ability at WOT where airflow is consistent is very easy with 2S EFI. Above 10 bar BMEP it is shutting the throttle approaching the apex where things go wrong. The motor loads up and won't come back on until it has cleared the Alpha-N over fueling out of its system. Alcohol based fuels would be a help here.

[TZ350]

<iframe width="560" height="315" src="https://www.youtube.com/embed/ZKNxrs7E-4s" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>

Successful Video of the Two Stroke Pseudo MAP concept: MAP gauge is bottom left.

Some smoothing required and the bike is just idling, I need another pair of hands to video a dyno run, but for now things look promising for a four stroke like MAP value that can be used in EFI VE volumetric efficiency tables. A realistic MAP value from a 2S that indicates real changes in air flow has to be a bit of a first, anyway I am excited about it. Hopefully, with a bit of development this might be the answer to that dreaded ride-ability problem.

At this point the indications are that the crankcase pressure (Max-Min)*3 = MAP concept could work....... :D

A better view of the MAP gauge:- https://youtu.be/xDixcBOg98U

[Tim Knopper]

the stock pipe delivers incredible midrange but falls off quickly after its peak at 8200 rpm where it was making 47.30 horsepower. With the Pro Circuit Works pipe installed, peak is moved to 49.60 horsepower at 8300 rpm. That is a 2.2-horsepower gain at peak, but most important, the pipe didn’t fall off as quickly after peak as the stocker. The Pro Circuit pipe made the same power as the stock pipe from 5000 rpm all the way to 7200, then the Pro Circuit pipe made 1 horse more at 7500 rpm, 1.6 more at 8000 rpm and 4 horses more at 9000 rpm.


Got pipe from DPR what a difference on the track

[TZ350]

Got pipe from DPR what a difference on the track

That is very impressive gains, I like it.

If your still looking to fuel inject it. More power and a wider spread and in the grey RPM zone. I would be vary wary as the better the symbiotic resonance in the system and pipe the less Alpha-N mapping will be possible as a complete fueling control strategy. You could drag race it no problems, but as far as fine throttle control is concerned you may have difficulties. I think you are truly heading into the area where you need a "Blended" approach. A mix of Alpha-N and VE volumetric efficiency. But producing a MAP or MAF value for the VE table is the trick with two strokes.

[wobbly]

I am working on a small race engine that has a pressure fed roller big end.
The original rod has the old fashioned copper M cage and the small end is too small ( both fail in race service ).
Thus I have tracked down a modern KTM rod that is sized for the same big end pin but uses a silver plated flat
big end and the small end is 1mm bigger.
All easy so far .
Both engines run the crank in the same direction and have the oil feed in from the same ( drive side ) flywheel.
BUT , the old pin has the oil feed hole on the trailing side , 90* from TDC.
The KTM has the feed hole on the opposite ,approach side , 90* from TDC.
Does it matter.

[Grumph]

I am working on a small race engine that has a pressure fed roller big end.
The original rod has the old fashioned copper M cage and the small end is too small ( both fail in race service ).
Thus I have tracked down a modern KTM rod that is sized for the same big end pin but uses a silver plated flat
big end and the small end is 1mm bigger.
All easy so far .
Both engines run the crank in the same direction and have the oil feed in from the same ( drive side ) flywheel.
BUT , the old pin has the oil feed hole on the trailing side , 90* from TDC.
The KTM has the feed hole on the opposite ,approach side , 90* from TDC.
Does it matter.

In my experience, no. So long as there's a positive pressure in the feed, it shouldn't matter.

[husaberg]

In my experience, no. So long as there's a positive pressure in the feed, it shouldn't matter.

So the reason the holes they are at 90's from TDC and BDC is the clearances are changed at either due to compression and inertia. or is it for fatigue?
Or is it all about crankcase pressures? or all of the above

[Flettner]

it's to give the crap in the oil a chance to centrifugal out. Clean oil only makes it out the hole. Me thinks.

Crap will eventually build up in the hollow crank pin, so therefore perhaps the leading side.

[husaberg]

it's to give the crap in the oil a chance to centrifugal out. Clean oil only makes it out the hole. Me thinks.

Crap will eventually build up in the hollow crank pin, so therefore perhaps the leading side.

Norton
https://i.ytimg.com/vi/4r2CVzzLaJc/hqdefault.jpg
Bsa
http://www.britishclassics.co.za/Portals/0/Blog/Files/2/30/WLW-BSAA65Thunderbolt1969_12959-CrankSludgeTrapOut_2.jpg
the Japanese decided a filter might be easier.
early Hondas and Xr200's etc combined both.

[Grumph]

it's to give the crap in the oil a chance to centrifugal out. Clean oil only makes it out the hole. Me thinks.

Crap will eventually build up in the hollow crank pin, so therefore perhaps the leading side.

While it is true that crap will eventually build up in a hollow pin - as I can show you in some 4T pins - in a race 2T the crank life is such that when stripped you'd have to look hard to find any in there....

Husa, your example is a 4T with recirculating oil - and very rudimentary filtration. Not really comparable.

[TZ350]

While it is true that crap will eventually build up in a hollow pin - as I can show you in some 4T pins - in a race 2T the crank life is such that when stripped you'd have to look hard to find any in there....

Also 2T oil is not contaminated with combustion carbon.

[husaberg]

While it is true that crap will eventually build up in a hollow pin - as I can show you in some 4T pins - in a race 2T the crank life is such that when stripped you'd have to look hard to find any in there....

Husa, your example is a 4T with recirculating oil - and very rudimentary filtration. Not really comparable.

Pretty sure wob was talking about a 4t as well:whistle:
What modern 2t have pressure fed big ends?

[Grumph]

Pretty sure wob was talking about a 4t as well:whistle:
What modern 2t have pressure fed big ends?

Where did he say it was modern ? LOL. Could have been something continental...

[husaberg]

Where did he say it was modern ? LOL. Could have been something continental...

Could have but i think he was sneaking 4t stuff in the thread.;)
notifce the pin on the later Honda F1.
Windage?
341159341160
i am guess the DLC and Crn2 are the coatings
so diamond like coating and hard Chromium nitrate
https://pubs.acs.org/doi/abs/10.1021/am404906x?src=recsys&journalCode=aamick
https://en.wikipedia.org/wiki/Chromium_nitride

[TZ350]

What modern 2t have pressure fed big ends?

Well maybe not "pressure" feed but my 2T is direct feed through the drive side crank shaft half ...... :cool:

[husaberg]

Well maybe not "pressure" feed but my 2T is direct feed through the drive side crank shaft half ...... :cool:

Anyone know what the aprilia D1 bottom end looks like?
looks pretty normal
341165341166

[Michael Moore]

Crap will eventually build up in the hollow crank pin, so therefore perhaps the leading side.

The 750 Laverda twin had oil slinger shrouds as on some 2T engines, and mine had sediment built up to the outside of the pin oiling gallery almost to the point of starting to block oil flow. Replacement shrouds that were held to the face of the flywheel with screws were made so cleaning would be easier (no need to scrub around with a bit of wire to try and loosen the sediment so it could be flushed out).

Small Hondas have a better arrangement with their oil filter cans that take the centrifuged oil out at the rotation axis, so there is a lot of space available to store sludge before having problems.

[wobbly]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

[TZ350]

Anyone know what the aprilia D1 bottom end looks like?
looks pretty normal
341165341166

The Aprillia DI direct injection SR50 crankshaft has a cam on one web to drive the DI air pump.

341167

Aprillia SR50 DI crankshaft

[Grumph]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.

Went through that with the mighty GN a couple of years back. Roller diameter is the major factor with the small 4T singles.
Going from a 4mm roller to a 3.5mm one made a massive difference in reliability.
Your next problem with the XR will be top end lubrication. You need a pressure feed into the cam with holes onto the lobe surfaces.

[wobbly]

Yea, the XR has oil fed around a stud up to the head.With the big overbore and resleeve that will go.
Will use an external hose and cooler.

[TZ350]

.
Success ....... https://youtu.be/xAp77XQx9R8


I have finally got the pseudo 2S EFI MAP co processor working well with the output smoothed. Now I have something useful to work with to explore the possibilities of using MAP and VE table with two stroke fuel injection.
.

<iframe width="560" height="315" src="https://www.youtube.com/embed/xAp77XQx9R8" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

[TZ350]

.
Ok, it is starting to look like I may have a winner.

Fueling is real rubbish but its what you would expect with a first cut.

The great news is that the Pseudo MAP value behaves like I hoped. It increases as the motor starts making power and drops in areas where the TPS increased but the motor did not fire. You can see that in the middle of the picture where the TPS (green line) increases but the RPM (white line) decreases because the motor did not pick up and the MAP (yellow line) and rpm dropped. To the right of the graph you can see where the motor picks up and the MAP follows suit. Fueling is crap so the traces are not very neat.

Altogether it looks like the concept is going to work.

In this graph the motor reeves out to 12,000+ RPM so I claim a world first, a 2S EFI successfully running in the 10/10 death zone with MAP and VE table.

Now all I have to do is figure out how to use Tuning Studio to improve the fueling. Get it running properly and ride it around the track ...... Lots to do yet.

341168
.

[husaberg]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.
Destroking one is easy insert XL125s crank 57mm becomes 49.5mm
For the hondas you can go down to a 3.5mm bearing using the Yamaha XT200 rod and Prox do a suitable bearing. From Memory
The DR200 is a longer rod option with 3.5mm rod bearing a well
Using a Yam rod allows you to either bush the little end or use a DR200 piston which is domed and about $200 cheaper than a wiesco.
Some of the odball Honda singles were also 30x37mm rod bearings but a little thinner generally.
GL145 has bigger valves pus roller bearing cam.

If tjhe rules are open i would just buy the franken motor off Drew.
Give it a decent bottom end and ignition.

Grass Kart?

[husaberg]

Im oh so sorry guys - yes the question was 4T related.
Real old XR200 being bored and destroked to pull 14,000 reliably.
The KTM up to 07 had the good roller setup, after that they went plain bearing as do the 4T Honda's but changing
the oil pump for plain bearings on an old XR is just too hard.
Grass Kart?
Destroking one is easy insert XL125s crank 57mm becomes 49.5mm
For the hondas you can go down to a 3.5mm bearing using the Yamaha XT200 rod and Prox do a suitable bearing. From Memory older cattledogs TKRJ do a siler 3.5mm 30x37mm silver plated no idea what design
The DR200 is a longer rod option with 3.5mm rod bearing a well
Using a Yam rod allows you to either bush the little end or use a DR200 piston which is domed and about $200 cheaper than a wiesco.
Some of the odball Honda singles were also 30x37mm rod bearings but a little thinner generally.
GL145 has bigger valves pus roller bearing cam.
What would worry me with destroking one would be the loss of comp that wil be unrecoverable
a flatt top gives 10:1 12 to one with a 125 shaped dome these engines love compression.
it will take a mighty big bore to get a decent lick of compression, going past 70mm is bloody hard

If tjhe rules are open i would just buy the franken motor off Drew.
https://sites.google.com/site/vpcrabtree/_/rsrc/1420339885159/home/xr200/vt250.JPG
Give it a decent bottom end and ignition.



I always preferred the CB100 gearbox over the XR200 6 speed, Much nicer ratios esp for racing.
but you would have to use 5 speed cases and the oil gallery is even closer on the 125's. no worries if you were intending on running it externally.

[TerraRoot]

Since we've mentioned a few foul-stokes here, (i'm in the middle of thinking about the conrod problem, and this talk reminded me) i'm converting 4T bottom end to take a 2T topend because the rules never said i couldn't.

what method would you use to block up all the holes in the 4T oil soaked crankcase? JB weld, braze, MIG, TIG? only really concerned about making an oiltight seal and not structural work.

[Michael Moore]

If you want to avoid welding then small tapped holes with plugs or tap bearing balls into an interference fit hole and then peen the edges over. I've seen the latter in some OEM applications.

[jbiplane]

Anyone can give good reference how easy calculate tension and compression force acting on conrod of 2-stroke?
Gas dynamic + acceleration... Any tool like engmod2t doimg that?

[F5 Dave]

Since we've mentioned a few foul-stokes here, (i'm in the middle of thinking about the conrod problem, and this talk reminded me) i'm converting 4T bottom end to take a 2T topend because the rules never said i couldn't.

what method would you use to block up all the holes in the 4T oil soaked crankcase? JB weld, braze, MIG, TIG? only really concerned about making an oiltight seal and not structural work.
That all seems a little nonsensical, however if it is making a mockery of some badly written rules then I'm all for it.:laugh: Pictures when you are in the guts of it please.

[Muhr]

Anyone can give good reference how easy calculate tension and compression force acting on conrod of 2-stroke?
Gas dynamic + acceleration... Any tool like engmod2t doimg that?

Do not know what is easy in life but, you may think it is worth reading.

https://hal.archives-ouvertes.fr/hal-01305936/document

[wobbly]

Sorry to derail the 2T talk guys , but its a 1/4 midget , so must use the XR/XL200 as a base.
Crank for the XR125 is as you say already a short stroke with the same basic forging, but the CB100 is alot nicer machined piece.
Moving the pin bore out to 51.8 is easy and using the shorter 98mm KTM rod gets the ratio back to a more suitable 1.89.
70mm bore is about it , offsetting the sleeve 1.5mm towards the exhaust - and im using a Yamaha 225 piston as it has a bigger 16mm stronger pin that matches the rod.
Biggest issue to me is that there is no 30/37 silver flat cage bearing available that I can find, there is in 38 ( with an extra needle as well )
and IMHO that is far more important for reliability than the roller size.
The old copper M cage is completely shite no matter what needle.
Race alloy roller rockers are made for the smaller Honda clone pit bike engines and using the spastic XR200 Megacycle cam makes
a correctly matched lobe profile easy to do with oversize Kibble valves and beehive springs/titanium retainers.
Not really my thing - but gives me a chance to use EngMod 4T for a change.

[Michael Moore]

Inertia load of reciprocating parts from Irving "Tuning for Speed" (pulled from a little spreadsheet I made)

Load at TDC in pounds = .0000142 W Nsq S (1+ S/2L)
Load at BDC in pounds = .0000142 W Nsq S (1 - S/2L)
W=weight of components in pounds
N = RPM
S = stroke in inches
L = length of con rod in inches

"sq" is squared, so RPM squared

I attached a copy of the spreadsheet that has some numbers I was looking at for a 200cc vintage single

Be sure to verify the numbers before applying to your project! This was made for my own use and I don't claim to be a professional spreadsheet creator.

cheers,
Michael

[husaberg]

Sorry to derail the 2T talk guys , but its a 1/4 midget , so must use the XR/XL200 as a base.
Crank for the XR125 is as you say already a short stroke with the same basic forging, but the CB100 is alot nicer machined piece.
Moving the pin bore out to 51.8 is easy and using the shorter 98mm KTM rod gets the ratio back to a more suitable 1.89.
70mm bore is about it , offsetting the sleeve 1.5mm towards the exhaust - and im using a Yamaha 225 piston as it has a bigger 16mm stronger pin that matches the rod.
Biggest issue to me is that there is no 30/37 silver flat cage bearing available that I can find, there is in 38 ( with an extra needle as well )
and IMHO that is far more important for reliability than the roller size.
The old copper M cage is completely shite no matter what needle.
Race alloy roller rockers are made for the smaller Honda clone pit bike engines and using the spastic XR200 Megacycle cam makes
a correctly matched lobe profile easy to do with oversize Kibble valves and beehive springs/titanium retainers.
Not really my thing - but gives me a chance to use EngMod 4T for a change.

I haven't seen the 225 piston
TKRJ do a 20mm ish wide 30-37 in silver but i have not seen the cadge. Not even sure what its for other than its for a Yamaha.
the early hondas had roller bearing crank (on one side Mag)as well as fully machined the 100's were generally 2mm narrower or something in the rod plus i think 14mm pin.
Also be aware the early stuff has a different spline on the primary there is a work arround but i cant remeber what it is maybe a mid model had the right 3.3 ratio primary rather than the 4.05 and the early spline and visa versa.
the cb100 box is 2.5-.965 from memory far nicer ratios thna the 6 speed.
That KTM rod was available in MMC no bearing a few years back, half the weight good for a year. according to the blurb
341181
Id be opening up the breathers as well.
One of the ATCs plus the TLR200 have bigger fined cylinders.

problem with them is one cam no ability to experiment with overlap.
Likely the only reason people raced Triumphs back in the day.
plus the Honda head was great in its day but there is little room to raise the ports.
But best 4t trail bike motor ever made,

[jbiplane]

I attached a copy of the spreadsheet...
Be sure to verify the numbers before applying to your project


Do not know what is easy in life but, you may think it is worth reading.
https://hal.archives-ouvertes.fr/hal-01305936/document

Thanks Muhr & Michael.
I did something similar in excel, but any additional references are very usefull :)

Parts of kreuzkopf engine for my respective customer (alternate to Ruger).
http://www.reaa.ru/yabbfiles/Attachments/Parts.jpg
According my estimations will work better. Weight of moving parts equal to stock piston.

[TerraRoot]

That all seems a little nonsensical, however if it is making a mockery of some badly written rules then I'm all for it.:laugh: Pictures when you are in the guts of it please.

Entirely nonsense and it'll probably take the better half of two years, provided i don't sire any more kids..

Thanks Michael for your response, but the holes are pretty big:
https://www.pitbikeparts.co.uk/images/medium/3-280714155921.JPG

That ain't the exact crankcase but it's similar, for giggles the specs will be a honda c50 41.4mm stroke crank and a 45mm mb5 topend, gotta sort a longer conrod to package the lot in and allow a roller cage small end.
if it made 10bhp i'd be happy, if it made 7 i'd still be happy because it would sound better.

I'm leaning toward the JB weld solution myself, anyone gonna tell me no?

[husaberg]

That all seems a little nonsensical, however if it is making a mockery of some badly written rules then I'm all for it.:laugh: Pictures when you are in the guts of it please.

The original husky that became the husaberg was made out of a two stroke bottom end.
they used reed valves controling crankcase compression and splash from the cam chain to move te oil arround.

[TZ350]

https://www.pitbikeparts.co.uk/images/medium/3-280714155921.JPG

I'm leaning toward the JB weld solution myself, anyone gonna tell me no?

Having glued up a fair few two stroke engine crankcases myself I would definitely go the glue way. I use Devcon F Aluminium putty myself but expect JB weld would be just as good. Glue from both sides of the hole with maybe a bit of light fiberglass matting worked in for good measure. Gluing from both sides locks the plug in. If you want to be doubly sure smear some clear Silicon glue over the out side to seal any air leaks if the plug works loose. You will be able to tell if there is a leak because the fuel will discolor the Silicon. Silicon is not fuel proof but sure seals air leaks and is a good tell tail. Anyway that is my thoughts. I like the idea of your project.

[guyhockley]

Looking at the work you're going to have to do to get a good seal around the crankcase, would it be worth seeing if you could transplant an existing 2T case into it?

[Frits Overmars]

Looking at the work you're going to have to do to get a good seal around the crankcase, would it be worth seeing if you could transplant an existing 2T case into it?How about a simple tin can? Or even better, a heat-insulating synthetic can?

[Grumph]

Looking at the work you're going to have to do to get a good seal around the crankcase, would it be worth seeing if you could transplant an existing 2T case into it?

Might be easier to simply fabricate a sheetmetal crank shroud - same shape as the inside of a 2T case.
All it's got to carry is a pair of seals so it doesn't have to be particularly strong.

Frits would appear to have faster internet than me, LOL.

[ken seeber]

Piston forces. During the Ryger period, I wrote a spreadsheet to get an understanding of the piston forces.

At the time, I did try posting it, but it was rejected as an Invalid file. Then a couple of days ago, Michael Moore successfully posted his spreadsheet. So, I sent mine to MM and he observed that mine had a file extension of .xlsx, rather than the .xls of his. He then converted it back to .xls, and voila, it worked. Cheers MM.

So, have a giggle if you want. Suggest you read the Explanation sheet first, you may get some understanding of it.

Warning…… Point 2 might be entirely correct.

341197

[mike schmidt]

Might be easier to simply fabricate a sheetmetal crank shroud - same shape as the inside of a 2T case.
All it's got to carry is a pair of seals so it doesn't have to be particularly strong.

Frits would appear to have faster internet than me, LOL.

My vote would be to set it up on a rotary table and mill the existing "shroud" away and at the same time mill a shallow pocket into the crankcase. Then turn some heavy walled aluminum pipe/ tubing to the correct I.D. / O.D. Cut it off so it sits a few thousands proud of the mating surface of the case. Bandsaw and belt sand it to fit the best you can. Clean everything, goop it up with epoxy and clamp everything together. Once it is cured, mill or lap the mating surface flush.

?????


Michael

[peewee]

guys this might not be easy question to answer considering different fuels, comp ratios , pipes, carb settings, spark lead, but do you think its possible to cool down to much the exh passage ?

[jbiplane]

Piston forces. Then a couple of days ago, Michael Moore successfully posted his spreadsheet.
341197
Great. Thanks Ken. Will modify and play with :)

[wobbly]

Considering that the Aprilia had 1L/Hp/min of cold coolant flow entering the cylinder, all of it fed in under the duct I doubt its
an issue.
But having said that rerouting the flow on a 125 kart engine to all of the cold flow fed across the transfers first ( with only a small 3mm feed each side
under the duct ) resulted in a good power increase.
Maybe by default not over cooling the duct ( and thereby overheating the transfers ) is a superior methodology.

[peewee]

Considering that the Aprilia had 1L/Hp/min of cold coolant flow entering the cylinder, all of it fed in under the duct I doubt its
an issue.
But having said that rerouting the flow on a 125 kart engine to all of the cold flow fed across the transfers first ( with only a small 3mm feed each side
under the duct ) resulted in a good power increase.
Maybe by default not over cooling the duct ( and thereby overheating the transfers ) is a superior methodology.

im still fiddling with the exh outer shell on the yami twins. debating to use alittle bigger shell than i first planed but im not sure if it would have to much water around the duct. ill get a photo and see what you think

[guyhockley]

Possible bike applications?

https://newatlas.com/acoustic-metamaterial-blocks-sound-not-air/58818/

[flyincat]

I'm in search of some advice on case porting a case reed motor, see attached pictures. As you can see, at BDC the piston covers quite a bit of the reed box exit into the crankcase. Plus, the cylinder tang blocks a good part of the center of the duct. Once the piston moves out of the way, things open up a bit, but the flow around the cylinder tang still doesn't look optimal. I did a lot of searching but couldn't find much info on directing flow front the reed tunnel to the crankcase. I assume Wobbly would be full of asymmetrical reed tricks to direct the flow up the sides, but I'm more curious about port shape for now. The other thought I had was on the edges of the reed box, where they aim at the transfer ports. Is it a good idea to radius the sides and top of the tunnel to turn the flow out and up, into the transfer ducts?

P.S. the intake and exhaust port are on the same side of the engine.

341247341248341249341250

[wobbly]

Contrary to the old wives dept pronouncements there is no useful flow from the reed tips until near TPO.
Thus cutting the piston skirt narrower does all but nothing - been there done that.
But cutting the tang into a tongue shape with a radiused face both vertically and horizontally does help flow,as does the side rads
as you have drawn.
If you can draw the reed block triangle shape on the side walls of the box, then tapering outward as they go inward , extra pockets above and
below the triangle will take advantage of spill over side flow from the reed.

[peewee]

wob dont you meen TPC ?

flycat there should be some rsa crankcase photo around here that will give you good ideas. as you probly already know, air fuel mix will be more willing to follow a radius corner (bigger the better) as opposed to something sharp, like your inlet sides where they enter the crankcase. ive also noticed on a few case reed designs that the inlet floor has some what of a upward ramp. i seen a cr250 with such a ramp . had a look at a new ktm which had a floor ramp also. cant figure out why the photos always go sideways from my phone but you get the idea

[flyincat]

Thanks, wobbly and peewee.

Regarding the tang, remember this is a non-conventional setup with the exhaust above intake. The top of the crank is rotating towards the intake, which makes that tang the primary thrust surface. I think your idea of making the tang tongue shaped would definitely open up some flow area, just not sure how much is safe to remove. Then again, the bottom of the tang is probably doing jack nothing for structure. Plus, the boost port (c port) is on the opposite side so the tang doesn't help divert flow into the boost port as it might with conventional engines. Most of the tangs on other engines I've seen are much smaller on the intake side. Is there any value in adding a 'splitter' to the roof of the duct to attach some flow to the tang?

341264

I couldn't find pictures of the aprilia reed duct but I found some good TM pics. Wob, I see what you're saying about the reed duct walls. My question is, what shape are the walls where they diverge from the square walls. Square walls in RED. What shape does the BLUE area actually take, looking from the top view? Is there a strategic aiming point (A duct, B duct, etc.) that the wall aligned with? Also, the radius on the top and side of the duct exit into the transfer ports is relatively small, maybe 6mm or less. Is there a reason not to make this radius much bigger? Maybe this gets back to the aiming?

341265 341266 341267 341268

[jfn2]

flyincat
Here are some pics (I hope) of some reed entries into the crankcase.
First is of the stock case, then cut down to the crankwheels and rounded into intake, metal permitting.
Last pic is of tangs hanging down into port that need rounded.

[flyincat]

jfn2 - Awesome pictures of the zuke! :cool: Thanks for sharing. That's quite a bit like I was imagining, except for the tang situation of the laydown engines. What power levels does that intake porting start to make a big difference? In the last picture, what's with the upwards boyesen ports??? Do those point up into the B duct? I'm having a hard time looking at the screen upside down and sideways to visualize where those go. haha

[wobbly]

My apologies yes TPC is correct - fingers slower than brain.
What you have here is a classic catch 22.You are trying to promote flow forward and outward , around the corner into the
cavity below the transfer duct entry.
But at the same time trying NOT to increase the area/volume in front of the reed block tip , as this does nothing in helping energy recovery
from the slowing intake velocity.
I have not actually tried this in a TM yet, but as you mentioned that biasing the flow regime to the upper reed ports works very well, then
by inference biasing the reed tip exit flow ( from the sides as well ) by creating a tapering outward ( as it goes forward) extra duct in the top
1/2 only above the triangle , would seem to be the logical extension.
But being a 2T this of course probably has no truck in reality.

[flyincat]

What is the reason, or sequence of events, that makes aiming the intake up into the transfer duct advantageous? If there is minimal flow through the reed until after the TPC, why worry about flowing into the transfer duct first? It can't be that it helps on the current intake/compression cycle. Is there a reason it's better to fill the hard to fill places (transfer ports) first?

[jfn2]

flyincat
Here are some more pics of the extra ports. This is not my engine so my info is limited. I have not done this to my cat yet but it is on one of the back burners.

[wobbly]

Dunno what the actual flow regime is inside a working engine - except to say that every time TM have angled the carb/reedblock downward
and angled the cylinder backward such that more flow exiting the reed tips is aimed at the transfer duct entries , it makes more power.
Same with agressively biasing the reedblock exit flow out from the upper reed ports.

[Vannik]

When the piston is moving upwards the space below it that it vacates is where the gas has to flow to. Most of it comes from the inlet so to minimize losses the inlet should be aimed at this space.

Secondary flow into this space also comes out of the crankcase and transfer passages. We want to minimize this last one and one way to do this is to lower the primary compression ratio - one often forgotten secondary effect of large case volumes. Often the side effect of the Boyesen ports is just that, rather than flow out of the transfer passages the flow is out of the inlet cavity which promotes reed opening.

[flyincat]

Ahhhhh, you guys are so smart! That makes sense...less turns to get the intake flow up the cylinder, where it mainly needs to go. I assume another key is to expose as many low pressure areas, in the crankcase, as possible to atmosphere to get the intake charge accelerated quickly. This creates momentum to pack the crankcase with extra charge as the flow comes to a halt, no? This may be getting too deep, but what about a high pressure wave coming back down the transfer duct after exhaust stuffing charge and TPC? There must be a return wave down the transfer duct(s) that meets up with the intake pressure wave somewhere in between?

[TZ350]

341293 125cc 1948 Villers Hayes Special. Open megaphones. Two Stroke.

Found myself in Invercargill yesterday and dropped into Hayes Hardware Store.

As well as the 125 Hayes Special I also wanted to take a look at Burts 200 mile an hour Indian Scout.

341298

Burt started with an Indian Scout like this one and spent years developing it.

341297 341296

Heaps of hand made and broken parts from the Indian and the Velo he was also working on.

The ever increasing speeds were painted along the top shelf of the broken parts he kept in his man cave come workshop.

341295 341294 Cleaned up and dressed in red for the museum.

How it is now after what must have been a life times work. Certainly the later part of his life was devoted 24/7 to the project.

In the end he managed a timed 200 mile an hour run at Bonneville.


Video clip:- https://www.stuff.co.nz/motoring/74327263/null

This video clip is of one of the film replicas but they do show what the bike looked and sounded like when Burt was actively campaigning it.


And of course a YouTube clip from the film "The Worlds Fastest Indian" portraying Burts 200 mile an hour run.


<iframe width="560" height="315" src="https://www.youtube.com/embed/tKnBURvKW4I" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>


One man with a dream working in his shed, I guess we can all relate to that.

.

[koenich]

thanks for that! love the "offerings..." shelf

[peewee]

some of you may find this useful. its a very nice thing and can print templates for making expansion chamber cones or cutting angles on pipes or making any size graph paper or making degree wheels of any size or many other things. https://www.blocklayer.com/

[husaberg]

thanks for that! love the "offerings..." shelf

In the offerings lower down is i think the aircraft engine head of a radial Curtis i think and a few broken alloy and complete rods.
The aluminium alloy rods were never successful as he tended to use what he could find easliy.
Although there was talk of him using a DC4 prop later on.

The steel ones were better the early ones were made out of Ford Truck axels these broke but the later ones were from broken Caterpillar Grader axles these were heated and power hammered into the basic shaped and then bored at teh ends byt hand shaped for the rest with handtools files hacksaw etc.
it used to take him a whole week which is about 100 hours for each.
He only used std Rollers from a very early indian as he liked their radiused ends up until near the end it had a single 20mm crankpin for both rods.

here is a pic of the original shelves in his workshop in 1972
341301
Here is the original Donaldson pre holidwood version.

https://www.youtube.com/watch?v=m-7juUCcSoU
https://www.youtube.com/watch?v=1lf3CaFj6K8
https://www.youtube.com/watch?v=5U1o-6OZ6Hs

https://www.youtube.com/watch?v=ih2reBw9ZmQ

[peewee]

Considering that the Aprilia had 1L/Hp/min of cold coolant flow entering the cylinder, all of it fed in under the duct I doubt its
an issue.
But having said that rerouting the flow on a 125 kart engine to all of the cold flow fed across the transfers first ( with only a small 3mm feed each side
under the duct ) resulted in a good power increase.
Maybe by default not over cooling the duct ( and thereby overheating the transfers ) is a superior methodology.

give me your best guess if its worth trying this larger cap. will be about 11mm water on top and bottom of duct. about 6mm on the sides { sides will have half moon cap welded over the aux ears}. probly use a right hand rad from newer ktm 250sx . higher flow water pump driven from the crankshaft is what I have now but maybe use electric down the road if I get ign with power to run it

[TZ350]

.

Ok its just another clip from the film but it does relate a famous beach race and that later the bikers were impressed enough to contribute financially to Burts next trip to Bonneville.

<iframe width="560" height="315" src="https://www.youtube.com/embed/bY55oqUDekg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

[Frits Overmars]

... will be about 11mm water on top and bottom of duct. about 6mm on the sides.You don't just want to push a lot of water through; you want to push it right along the hot walls. If you keep the gap tight, more of the water will come in contact with the walls, and it will flow faster as well. I'd consider 6 mm the maximum gap. If the pump can deliver enough pressure, I'd go down to 5 mm.

[peewee]

thanks frits that makes perfect sense. ill go back to my original plan

[Grumph]

.

Ok its just another clip from the film but it does relate a famous beach race and that later the bikers were impressed enough to contribute financially to Burts next trip to Bonneville.

I learned a few years back to be wary of buying a '60's road bike with Invercargill ownership. The Triumph I rebuilt looked like it had not only been beach raced - but left on the beach and dug up next day.
Burt went to the US by boat of course. The trip was long enough that he'd take a vice and files and a set of part finished rods along - and finish them on board.

[TZ350]

.
Ok. Another bump in the road. The 2S EFI fuel injected two stroke Pesudo MAP thing works pretty well.

BUT .... there seems to be another issue that comes up when the throttle is closed ie TPS = 0%.

With the pseudo crankcase pressure MAP (Phigh - Plow)*3. I get a range of 0.2 bar, TPS = just open and motor firing to 0.9 bar, TPS fully open and engine firing. The motor responds to changes in MAP value just like you would expect.

But with the throttle fully closed ie TPS = 0% the pseudo MAP value is 0.6 bar when it should be 0.2 at most. Maybe this is due to the atmospheric pressure at the stinger/muffler outlet overcoming weak suction by the pipe and pushing exhaust gas back into the crankcase.

And without the suction action of the pipe the residual average pressure in the crankcase is higher than it would be if the throttle was a little open and the motor firing well enough to get some suction action going in the pipe.

I think the 0.6 bar at closed throttle is the result of (Phigh - Plow)*3 working on a large volume/density of contaminated gases filling the crankcase whereas, as soon as the throttle is opened a fraction and the motor fires properly the pipe sucks on the crankcase and the pseudo MAP value drops back to 0.2 bar.

The EFI CPU can't work with 0.6 bar for two entirely different situations.

So the fix might be to bring the TPS into the mix and when it is = 0% then force the pseudo map to be 0.2 bar. Easy enough to do with some software changes and I hope to try it soon. There is another interesting project on the dyno at the moment so it might be a week or so before I can get back to the 2S EFI project.

[husaberg]

I learned a few years back to be wary of buying a '60's road bike with Invercargill ownership. The Triumph I rebuilt looked like it had not only been beach raced - but left on the beach and dug up next day.
Burt went to the US by boat of course. The trip was long enough that he'd take a vice and files and a set of part finished rods along - and finish them on board.

Thats also where he found and cut up an aircraft radial. i cant remember whati t was but it used a Catalina spark plug.
Whats not well known was he did all sorts of experiments turning the Indian into a single for grass track converting it to DOHC all sorts of wonderful stuff.
After he converted the indian to OHV it took him a few years to get it back to how fast it was on a SV.
The heads on the Indian were copies of a 1920's AJS.
Ed Iskenderian (IE IEsky Cams)offered to buy the cams out of the Indian for a huge amount of cash Bert couldn't get them out fast enough.
Yes he did use gas pipe fpr the cylinders but it made sense to as they were spun high grade cast iron
The Velo wasnt that much slower than the indian either.

[wobbly]

The trend has been for several years to reduce cooling water jacket volume and to increase flow velocity.

[shnaggs]

.
Ok. Another bump in the road. The 2S EFI fuel injected two stroke Pesudo MAP thing works pretty well.

BUT .... there seems to be another issue that comes up when the throttle is closed ie TPS = 0%.

With the pseudo crankcase pressure MAP (Phigh - Plow)*3. I get a range of 0.2 bar, TPS = just open and motor firing to 0.9 bar, TPS fully open and engine firing. The motor responds to changes in MAP value just like you would expect.

But with the throttle fully closed ie TPS = 0% the pseudo MAP value is 0.6 bar when it should be 0.2 at most. Maybe this is due to the atmospheric pressure at the stinger/muffler outlet overcoming weak suction by the pipe and pushing exhaust gas back into the crankcase.

And without the suction action of the pipe the residual average pressure in the crankcase is higher than it would be if the throttle was a little open and the motor firing well enough to get some suction action going in the pipe.

I think the 0.6 bar at closed throttle is the result of (Phigh - Plow)*3 working on a large volume/density of contaminated gases filling the crankcase whereas, as soon as the throttle is opened a fraction and the motor fires properly the pipe sucks on the crankcase and the pseudo MAP value drops back to 0.2 bar.

The EFI CPU can't work with 0.6 bar for two entirely different situations.

So the fix might be to bring the TPS into the mix and when it is = 0% then force the pseudo map to be 0.2 bar. Easy enough to do with some software changes and I hope to try it soon. There is another interesting project on the dyno at the moment so it might be a week or so before I can get back to the 2S EFI project.


Very interesting what you are finding, I'm not quite sure if I'm following you but I might be experiencing something similar to you...Ok hear me out! New KTM 125 on the dyno, I couldnt stand how hard the throttle was to turn, so I did the old trick I used to do when I raced and I took the spring out of the carb and took it to the belt sander, sanding off a bit of material around the DIA. After doing this I swear I can notice a difference in how hard it is to open the throttle in different running scenarios. I think it might be because I can now feel when the crank case has more pressure in it, so the slide has more resistance on it and it is a bit harder to open. If I do light throttle blipping I dont notice it, but If I go WOT to peak RPM and let it speed come back down, thats when I notice the throttle is harder to open next turn.

[TZ350]

341346 Cully and Ellie at Tokoroa 2nd in the New Zealand Miniature RR Sidecar GP.

Guess what exciting CVT project Team ESE have on the dyno ......;)

Its our first experience with setting up CVT's, very interesting system to work with. So easy, we are looking to make a F4 bike now with CVT.

We have a few spare Suzuki V100 two stroke power units to salvage for CVT parts.

Now Ok where did I leave that spare RS125 NX4 rolling chassis and the 32hp NSR/GP110 engine ....... a bit of work with a hacksaw and tig welder, marry a few parts up and we should have something interesting for next season.

[lodgernz]

341346 Cully and Ellie at Tokoroa 2nd in the New Zealand Miniature RR Sidecar GP.

Guess what exciting CVT project Team ESE have on the dyno ......;)

Its our first experience with setting up CVT's, very interesting system to work with. So easy, we are looking to make a F4 bike now with CVT.

We have a few spare Suzuki V100 two stroke power units to salvage for CVT parts.

Now Ok where did I leave that spare RS125 NX4 rolling chassis and the 32hp NSR/GP110 engine ....... a bit of work with a hacksaw and tig welder, marry a few parts up and we should have something interesting for next season.

Wasn't Cotswold developing a CVT bucket using an SX50 or 50SX?

[Michael Moore]

You may find the Aaen Performance guide to "clutch"/CVT tuning to be of use

http://www.aaenperformance.com/Handbooks.asp

[TZ350]

Wasn't Cotswold developing a CVT bucket using an SX50 or 50SX?

Yes ..... it should be interesting.


You may find the Aaen Performance guide to "clutch"/CVT tuning to be of use

http://www.aaenperformance.com/Handbooks.asp

Thanks.

[JanBros]

totaly off-topic, but I just wanted to share : my new twin shock linked progressive suspension :banana: needed something like this because normal moped suspension isn't suited for jumps and we already bent 3 frames leftwards-up (shock bottoms-out , force transmitted to the frame only on the left side) because of crap riders who think they can jump :tugger: :innocent:

http://users.telenet.be/jannemie/SKY/dub%20prog%202.JPG

http://users.telenet.be/jannemie/SKY/dub%20prog%201.JPG

made a right-side swing-arm and put a softer springed shock on the left in series with a harder springed shock on the right through 2 arms and an axle that can turn. length of the arms determines the hardness of the spring as they are compressed from both sides : first the hard one acts as a push-rod, compressing the soft one also from above, and when that one is bottomed out, the soft one acts as the push rod and the hard one is compressed from both sides.

[wobbly]

Dead cool, so as the lever angles change ytou get geometric rising rate along with the spring rising rate.

[Grumph]

Personally, I like the cable tie bead locks...

This sort of activity is best done with hire scooters.

After one well-known episode here, several were handed back folded up like pocket knives.

[JanBros]

Dead cool, so as the lever angles change ytou get geometric rising rate along with the spring rising rate.

didn't do the math if that is realy true, I'm already very happy that now I have a hard spring that can handle jumps and a softer that keeps my wheel on the ground and gives me better traction everywhere else.

I can play with different springs, pre-load, length of the arms and can even make axles with different angles. That should be enough to find a good set-up :)

[TZ350]

I just wanted to share : my new twin shock linked progressive suspension :banana:

http://users.telenet.be/jannemie/SKY/dub%20prog%201.JPG


Very clever suspension, I love it and "Powered by Imagination" I love that too.

[Mike Fisher]

This Red Rocket Honda CR250 was built Andy Bondio for John Kocinski, he holds the lap record at Perris, Ca. short track on it. Its special, all Ti & carbon fibre, 156bs (71kg), apparently single speed gearbox (to save weight?). The shroud seems to cover the whole air cooled top end so is not just to protect the rider's knee so must be for cooling. I'm interested in the shape of the expansion chamber, the step in the divergent cone appears to be very steep, any opinions?
341430

[wobbly]

No technical reasoning behind the super steep last divergent section at all.
The pipe would have made better power if the preceeding cone was extended at a steeper angle all the way up to the
mid section.
Its got a very shallow rear cone as well, probably trying to smooth out the wierd torque dips created by the diffuser.

[190mech]

Could be a "CTC" pipe(confuse the competition) and the actual pipe lies within the BS external skin..

[F5 Dave]

Could be big change in colouring at that intersection. However change in temp too. Can you imagine anyone obsessed with a seriously light bike being able to bring themselves to putting 1/3kg of pipe covering over?

[husaberg]

This Red Rocket Honda CR250 was built Andy Bondio for John Kocinski, he holds the lap record at Perris, Ca. short track on it. Its special, all Ti & carbon fibre, 156bs (71kg), apparently single speed gearbox (to save weight?). The shroud seems to cover the whole air cooled top end so is not just to protect the rider's knee so must be for cooling. I'm interested in the shape of the expansion chamber, the step in the divergent cone appears to be very steep, any opinions?
341430

The engine a early 80's air cooled Cr250 hence the air cooling about 80-82 I would say.
https://www.jkracinguk.com/images/images/31945546.JPG
Lil jon was quick on the dirt as fast as Kenny Eddie and Wayne maybe faster as they had a play to slow it down his XR100 back when he was racing for Kenny.
According to legend He used to clean his gear with a toothbrush.

[peewee]

well not nearly as much progress as I hoped but its still going. outer shells are tacked on and the end caps are fitted and ready to weld when I get a moment. the mini torch should work a treat for the end caps. included a photo to show how ill do it. was giving some consideration of cutting oval water ports to cool down the exh spigot face like wobbly has mentioned but I wonder if there would be any trouble with water leaks at the spigot/cylinder junction

[katinas]

Havoc 100 cc cylinder made with attention to EX cooling.

[TZ350]

341452 Cully and Ellie

Red line is where the Team ESE's bog standard 150cc 4S was at when this picture was taken at the Tokoroa GP ..... :second:

341453

Blue line is where its at now after playing with the CVT's rollers and springs. Roll on the next meeting at Whangarei....... :banana:

[TZ350]

341456

We are looking at resurrecting this old four stroke two stroke hybrid project.

The sidecar with a 28hp two stroke motor and CVT could be real exciting.

[ken seeber]

Look what I saw on a particular KTM 300EXC TPI today.

341459341458



Is this a special commemorative model ?? Who knows.

Maybe if someone has a buddy at KTM, they could ask them.

Such a mystery.. :confused:

[DaisyB]

341456

We are looking at resurrecting this old four stroke two stroke hybrid project.

The sidecar with a 28hp two stroke motor and CVT could be real exciting.

341468
This one with 42bhp (Gilera Runner 180) was sure fun! Annoyed quite a few big classic chairs along the way.

[TZ350]

This one with 42bhp (Gilera Runner 180) was sure fun!

341468

Annoyed quite a few big classic chairs along the way.

Great Fun........ I love it.

341473

Now to find some Gilera 125's. Should be able to de stroke them to 110 easily enough. Seems to be plenty of after market tuning parts available.

[mprestwi]

341475341476

Hello gentlemen, well since there appears to be a slight lull in the action I thought I might take the opportunity to jump in. I have been following this thread with awe for some time now and am totally amazed by the geniuses and brain trust contributing. I am incredibly grateful for the shared knowledge, have learned a lot and want to learn more.

Anyway as I sit in Northern Canada waiting for the snow to recede (more than my hairline). I thought I’d pose a question I have a few others tucked away but figured no sense unloading all at once.

In the interest of keeping things cool are there any other good tips on reducing thermal migration besides what was already mentioned about insulating ceramic coatings? I know F1 have been doing some of this.

I’ve included a pic of a few things I’ve done to my RZ to try and help. Added a red silicone baking sheet to the frame to isolate pipe heat from the crankcase and added RC motor heatsinks to the pipes with thermal paste to keep the first few inches of the pipe cool (learned that great piece of advice on this blog). One thing you can’t notice is the titanium flange nuts holding on the pipes. I used them because the thermal conductivity is less than steel (or stainless). That should (in theory at least) reduce the heat path from the pipe flange, through the nuts, along the studs and into the cylinder. Not much I’m sure but I’m thinking all the little bits help and might add up to something.

Other pic shows my oil filler plug heat pipe dragging oil heat up from the depths to dump it out to ambient. Uses acetone as the working fluid due to it’s low boiling point. Geez I hope I did this right and attached the pics properly. First time posters always have issues.

Anyway any other tips would be great. I apologize if his may have been covered in detail before but I have only been able to sift through about 500 pages of this gem of a discussion so far.

[F5 Dave]

Look what I saw on a particular KTM 300EXC TPI today.

341459341458



Is this a special commemorative model ?? Who knows.

Maybe if someone has a buddy at KTM, they could ask them.

Such a mystery.. :confused:

Hahahaha :banana:

Nice one, made me laugh and laugh.

[TerraRoot]

341468
This one with 42bhp (Gilera Runner 180) was sure fun! Annoyed quite a few big classic chairs along the way.

42bhp! got 20bhp at the wheel for mine, but with stock ports, just barrel height adjustment. felt the 180 was quite alot like the yamaha 350, large bore squished in transfers.
so did you manage 42bhp with the stock reed valve? haha

[peewee]

341475341476

Hello gentlemen, well since there appears to be a slight lull in the action I thought I might take the opportunity to jump in. I have been following this thread with awe for some time now and am totally amazed by the geniuses and brain trust contributing. I am incredibly grateful for the shared knowledge, have learned a lot and want to learn more.

Anyway as I sit in Northern Canada waiting for the snow to recede (more than my hairline). I thought I’d pose a question I have a few others tucked away but figured no sense unloading all at once.

In the interest of keeping things cool are there any other good tips on reducing thermal migration besides what was already mentioned about insulating ceramic coatings? I know F1 have been doing some of this.

I’ve included a pic of a few things I’ve done to my RZ to try and help. Added a red silicone baking sheet to the frame to isolate pipe heat from the crankcase and added RC motor heatsinks to the pipes with thermal paste to keep the first few inches of the pipe cool (learned that great piece of advice on this blog). One thing you can’t notice is the titanium flange nuts holding on the pipes. I used them because the thermal conductivity is less than steel (or stainless). That should (in theory at least) reduce the heat path from the pipe flange, through the nuts, along the studs and into the cylinder. Not much I’m sure but I’m thinking all the little bits help and might add up to something.

Other pic shows my oil filler plug heat pipe dragging oil heat up from the depths to dump it out to ambient. Uses acetone as the working fluid due to it’s low boiling point. Geez I hope I did this right and attached the pics properly. First time posters always have issues.

Anyway any other tips would be great. I apologize if his may have been covered in detail before but I have only been able to sift through about 500 pages of this gem of a discussion so far.

you might be able to use heat reflecting tape in some areas. i bought some and eventually will bench test it to see how well it work. my reason for trying it is ive got aluminum fuel tank behind the radiators and above the cyl head. so its soaking up heat from several directions

[Grumph]

you might be able to use heat reflecting tape in some areas. i bought some and eventually will bench test it to see how well it work. my reason for trying it is ive got aluminum fuel tank behind the radiators and above the cyl head. so its soaking up heat from several directions

Yoshimura used to use an insulating mat under their tanks. I believe it's the same stuff used on the floors of NASCAR cars to try and keep the drivers boots from melting. US made - should be available from race suppliers.

[mprestwi]

Thanks for the tips gentlemen. I am also toying with the idea of a method to heat shroud the intake from warm air.

[speedpro]

I had a similar concern with a turbo Z1 engined bike. Very very hot engine with the turbo just behind, all parked beneath 15L of fuel. Went with a white blanket of high temp insulation between layers of foil tape. All up about 10mm thick. The insulation was incredible and could withstand a blow torch according to the brochure. Had a little framework on the bottom of the tank which it slipped into. Had a similar setup on the turbo exhaust outlet but with fibreglass tape over the insulation and held in place with a mesh guard. It took the worst of the heat off my left leg. Road race, not drag race.
I would also think some well polished thin shield with a small airgap would be effective. Something like very thin stainless steel.

[136kg136ps]

My turbo and oil filters were too close to my air intake on my fishing boat due to a very cramped engine room.Turbo heat shields are another option.
This stuff can be really close to exhausts without scorching.


https://www.heatshieldproducts.com/marine-heatshield/marine-heat-shield-insulation

[DaisyB]

42bhp! got 20bhp at the wheel for mine, but with stock ports, just barrel height adjustment. felt the 180 was quite alot like the yamaha 350, large bore squished in transfers.
so did you manage 42bhp with the stock reed valve? haha

Not quite stock! Pm Tuning 172 barrel -transfers welded and re-shaped, stroked to 55, RD350 Vforce4 reed (just a whiff of welding!) Tillotson 34 carb & a Jahspeed blown pipe. (Which really shouldn't have worked but did)

[TZ350]

.
Well after a bit of traveling away for work, a grand tour of New Zealand's South Island and helping out on the sidecar CVT project last week I have finally been able to get back to my fuel injection project.

I had the pseudo MAP co processor working and responding as hoped. But I was puzzled for a bit about why, when the throttle was completely closed the crankcase pressure went up. On reflection I figured that when there was no suction from the pipe atmospheric air and exhaust fumes flooded back up the exhaust pipe and through all the gaping holes in the cylinder.

Filling the crankcase to near atmospheric pressure with dirty exhaust gave the underside of the piston something to compress resulting in a misleading high pseudo MAP value. The crankcase pseudo pressure quickly dropped, actually the difference between max - min crankcase pressure dropped as soon as the pipe started sucking again and the piston was left chasing air that was rapidly disappearing up the transfer ports.

Some tweaks to the co processors software soon sorted that and now my two strokes pseudo MAP value looks much like you would expect from a four strokes MAP sensor and hopefully will be a good indication of changes in mass air flow for the EFI's CPU to work with.

I expect, with a bit more software tweaking and some time tuning the fueling map with Tuning Studio I might soon have a fuel injected two stroke bike I can race.

:D
.

[wobbly]

Just in case anyone is interested , the question I asked about the position of an oil feed hole in a big end pin.
The answer is its of no importance as long as its away from the highest load positions at TDC and BDC.
The side position ensures the squeezed oil film in the high load area does not all but block off oil flow.

And back to 2T reality - TeeZee , your fight with the injection system using good tech and electronic nouse is a real inspiration.
Hope you find the keys buddy.
And then we can all sit back and know it was on here first.

[cotswold]

341456

We are looking at resurrecting this old four stroke two stroke hybrid project.

The sidecar with a 28hp two stroke motor and CVT could be real exciting.

I think I could be persuaded to throw a leg over that

[TZ350]

And back to 2T reality - TeeZee , your fight with the injection system using good tech and electronic nouse is a real inspiration.
Hope you find the keys buddy. And then we can all sit back and know it was on here first.

Thank you for the encouragement.

The 2S pesudo Map (Yellow line) is starting to behave like a good MAP should but is cutting out at about 6,000 rpm (White line). Also interesting is that on overrun when the throttle (Green line) is opened a crack and the motor fires the MAP line shows a peak indicating increased air flow through the motor.

341502

The pseudo map co processor code works well with the simulator and checks out Ok on the scope. The simulator simulates rpm and high and low crankcase pressure up to 14,000 rpm. So I think that the map sensor itself may not be able to keep up with the changing crankcase pressure. Or the peak pressure moves away from the sampling point. The processor is not fast enough to sample continuously so for high pressure I read three points around 135 deg atdc and keep the highest. I will have to try different crank angles and maybe some different map sensors.

341503

The yellow dots are pressure samplings and the purple line is simulated crankcase pressure, RPM is a bit over 12,000 in this picture. The Volt meter is reading the pseudo MAP value.

[TZ350]

Just in case anyone is interested , the question I asked about the position of an oil feed hole in a big end pin.
The answer is its of no importance as long as its away from the highest load positions at TDC and BDC.

Its interesting about crankshaft B/Ends. The most wear is on the underside of the B/E pin and greatest on the side closest to a main bearing. Makes sense when you think about it. Because the underside takes all the loading at TDC and BDC and the side nearest a main is unable to flex away from the load.

341504

[lodgernz]

What is the general opinion on the amount of gap either side of the small end bearing to the inner faces of the gudgeon pin bosses?
I want to use a piston that has a space of 18.7mm between the bosses, but the widest bearing I can find is only 17mm wide. Does this sound like a disaster waiting to happen if I use it?
A second possible issue is that the conrod small-end eye is only 13.5mm wide.
I'd appreciate any advice on this. The rod is located by the side plates on the crankpin.

[wobbly]

The only issue to consider is that disaster is likely if the caged needle ends can slide sideways sufficiently to overhang
the rod small end bore.

[lodgernz]

The only issue to consider is that disaster is likely if the caged needle ends can slide sideways sufficiently to overhang
the rod small end bore.

Thanks Wobbly, of course the needle is the issue, not the cage as I was thinking.
The needles in this bearing are 13.0mm long, so worst case scenario, if the bearing moves hard up against one of the pin bosses, which I imagine it will, the needles will overhang the eye by 0.4mm.
That's assuming the rod stays central. Although 0.4mm doesn't sound like much, I guess it could cause the ends of each needle to become less worn compared with the central part. I've no idea how significant that is.

Would it be safe to add a thin alloy shim either side of the bearing? Or some other material? Obviously they only need to be 0.5mm thick to prevent the above situation.

[wobbly]

I have seen hard anodised alloy spacers used for exactly what you are trying to prevent, needle overhang.

[lodgernz]

I have seen hard anodised alloy spacers used for exactly what you are trying to prevent, needle overhang.

Thanks again Wobbly. So that's my solution.

[TZ350]

.
In one of the Team ESE GP's we used anodized alloy spacers like Wob described (common in KT100's). We used them for years, probably still going. And the Suzuki RGV250 uses steel spacers at the little end.

[F5 Dave]

Needle overhang will cause the needles to dig in to the sharp edges of the rod, securely clamping onto the gungeon pin and thrusting it sideways overwhelming the circlip and into the bore.
Don't ask how I know:rolleyes:

[TZ350]

341508

In my Suzuki GP-NSR110 engine I use a pair of RGV250 little end thrust washers to centralize the little end bearing because it is several mm shorter than the gap between the piston pin bosses.

In the picture there is also the Kawasaki KE175 rotary valve cover, over-sized be spoke RV blade, RD400 con rod, RGV250 big end bearing and extra long big end pin for the widened crankcase, de stroked crank and not seen is the NSR250 cylinder.

[TZ350]

341510 341509

A bit of progress on the 30rwhp Suzuki GP-NSR110 F4 CVT project. Used the drop saw to hack the CVT gearbox out of the old scooter power plant.

341511 341512

I am planning on joining the CVT gearbox to the Suzuki crankcase by mounting the gearbox on a 12 mm alloy plate and inserting the plate between the crankcase halves like I did with the first GP-NSR110.

341513

[peewee]

got alittle more done. ill try to get the side caps welded on this weekend

[TZ350]

341524

The 50 at the salt this year. Holed a piston after 3 miles at full noise over the run up and part way through the timed section.

The speed was good, just have to figure out how to tune the bike on the dyno in Auckland NZ so it holds together on the salt at Gardner Lake Aus.

[TZ350]

341527 341528

Tim riding one of Team ESE's RG50's took :first: in the AMCC F5 cup :second: in the North Island series and :third: in the NZGP national title. Good one Tim. :niceone:

341529 Tim (34) in another life.

[TZ350]

341530 ridiculous loads of crankcase volume.

For the F4 110cc CVT project I was going to make a traditional style of crankshaft but have decided to test the "more is better" crankcase volume theory.

The theory has it, that with a good pipe the more crankcase volume there is the more air/fuel the pipe can suck into the cylinder as it is easier to take a deep breath from a room full of air than from a thimble. Being CVT I wont have to worry about crankcase pumping at lower RPM of the pipe because the clutch on this thing will be set to kick in, well into the torque curve at 9,000 rpm and setup to run through to 13,000 or so.

The Suzuki V100 scooter crank already is the correct stroke so I will just bore the pin holes to 22mm for the RD400 rod. If this does not work, plan "B" is to de stroke the crank and fit a performance aftermarket cylinder for 70cc and turbocharge the sucker to fill up that case volume. We already have a brand new miniature turbo the right size.

[peewee]

if you can just get one side fitted then trace it on paper for a template on the other three sides. on another note. im ordering a right side rad from the newest 250sx that should work great for this engine. ill just reposition the hose nipples and add some mounting brackets . ill report back in a few days when that shows up

[Grumph]

341530 ridiculous loads of crankcase volume.

For the F4 110cc CVT project I was going to make a traditional style of crankshaft but have decided to test the "more is better" crankcase volume theory.


I'll be watching this...The pic is just like looking into my Villiers 197 special, lol.
If you make it work, I'll hold off on finishing the full circle crank - cut down DT360.....

[TZ350]

.

There are some hugely talented people in the motorcycling world in general who have so much energy and do such incredibly interesting work, I take my hat off to them....... :drinknsin


<iframe width="560" height="315" src="https://www.youtube.com/embed/yc0MUB7nk1Q" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>


Check out the width of that small cylinders exhaust port.

[F5 Dave]

Gee, why stop at 170* bore width? Go for 350.

[husaberg]

I cant seeing it bettering 70HP at 30,000RPM.
Hes having a go at plating it himself.

[TZ350]

.



Gee, why stop at 170* bore width? Go for 350.

We experimented with 85% in a 50, as a way of trying to get the required blow down time area at 14,000 and an ideal exhaust port and pipe resonant timing of 192 - 194 duration.

85% on the small 50cc cylinder worked Ok without breaking the (steel) ring but we managed to ruin the cylinder in other ways.


318368318372

Ok started on learning how to model a 85% profiled exhaust in Engmod2T.

[peewee]

.

There are some hugely talented people in the motorcycling world in general who have so much energy and do such incredibly interesting work, I take my hat off to them....... :drinknsin


<iframe width="560" height="315" src="https://www.youtube.com/embed/yc0MUB7nk1Q" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>


Check out the width of that small cylinders exhaust port.

I try to watch a few of the videos when time allows. my hats off to him for giving it a go. I hope it works out :headbang:

[peewee]

got a bit more done today. even though the cylinders are squashed together so bad, im going to make the water jacketing around the aux ears go as far toward the rear of the cyl as I possibly can. the 250sx radiator will be here tomorrow and wonder how you think the best way to route the water hoses into it ? youll see what I meen in the photo. what im thinking to do is weld on a elbow to each cyl near the exh spigot. then either have the hoses go into a Y and then just a single inlet into the top of the rad or keep both hoses separate and run both into the top of the rad. it would be simpler to just weld on one hose nipple rather than two. do you guys see any reason not to use a single hose into the rad rather than two ?

[lodgernz]

.

There are some hugely talented people in the motorcycling world in general who have so much energy and do such incredibly interesting work, I take my hat off to them....... :drinknsin


<iframe width="560" height="315" src="https://www.youtube.com/embed/yc0MUB7nk1Q" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>


Check out the width of that small cylinders exhaust port.

I think he's planning to use a "retained" ring, i.e. reverse Dykes, so port width shouln't be a problem, nor should exhaust-to-transfer leakage as there would be no pin holes.

[lohring]

If you don't have rings, the limitation is the piston falling out of the exhaust. Below is a stock sleeve on the right and a modified sleeve on the left for a 7.5 cc race engine.

Lohring Miller

341555

[DaisyB]

As we seem to be on Ex ports at the moment, is there an accepted "safe" % of bore width for a briged port?

[TZ350]

As we seem to be on Ex ports at the moment, is there an accepted "safe" % of bore width for a briged port?

My understanding is that a problem arises when the exhaust port gets wide enough for the piston pin to allow a short circuit path between the "A" transfer and the ear of the exhaust port. After that, extra width starts to become counter productive.

[polcat88]

Hello all, and thank you for sharing your knowledge on this great forum.

My name is Steve and I live in Sarnia, Ontario, Canada. I drag race snowmobiles on both ice and grass. My current project is a 1047cc three cylinder, case reed induction, Suzuki engine, based on an Arctic Cat F7 two cylinder engine. 79.7 X 70 bore and stroke with auxiliary exhaust ports. After reading this thread it is obvious that snowmobile cylinder design is not at the level of today's best technology and I am hoping to rework a cylinder and start dyno testing. To that end, I need some clarification regarding the "Wobbly" exhaust duct. My thinking is as follows:

Raise the exhaust port floor to the point of effective transfer opening at the bore and then fill in the port floor enough to carry a 25 degree angle to the end of the spigot.

Weld and cut the duct roof at an angle greater than 25 degrees such that the area is reduced to 75 % of the original effective port area at the bore, at a length of 1.5 times the bore diameter 119.5mm.

Then cut the spigot roof at an angle of "X" degrees to achieve an opening of 100% of the original effective port area at a length of 2 times the bore diameter 159.5mm.

Is my thinking correct that all area changes are made by changing the angle of the duct and spigot roof, and the width of the complete setup is the same from the port to the end of the spigot?

If the above is correct is the transition from duct to spigot left sharp or radiused? If radiused, how much of a radius?

I can't seem to find much information with regards to the passages from the auxiliary exhausts. From the posted pictures, it looks like the passages exit the spigot at close to the horizontal centreline. Is the centreline of the spigot end the exit target or should these passages be ran at 25 degrees the same as the floor of the duct and spigot and exit wherever that puts them?

How is the sizing and the inward angle of the auxiliary passages determined? A semicircle equal to the height of the auxiliary port angled inward enough to still have the same semicircle at the end of the spigot?

Any and all help is appreciated.

[F5 Dave]

My understanding is that a problem arises when the exhaust port gets wide enough for the piston pin to allow a short circuit path between the "A" transfer and the ear of the exhaust port. After that, extra width starts to become counter productive.
But as a rule, in racing you have to give 110%, so that seems a good place to start.

[Frits Overmars]

Hello all, and thank you for sharing your knowledge on this great forum.
My name is Steve and I live in Sarnia, Ontario, Canada. I drag race snowmobiles on both ice and grass. My current project is a 1047cc three cylinder, case reed induction, Suzuki engine, based on an Arctic Cat F7 two cylinder engine. 79.7 X 70 bore and stroke with auxiliary exhaust ports. After reading this thread it is obvious that snowmobile cylinder design is not at the level of today's best technology and I am hoping to rework a cylinder and start dyno testing. To that end, I need some clarification regarding the "Wobbly" exhaust duct. My thinking is as follows:
Raise the exhaust port floor to the point of effective transfer opening at the bore and then fill in the port floor enough to carry a 25 degree angle to the end of the spigot.
Weld and cut the duct roof at an angle greater than 25 degrees such that the area is reduced to 75 % of the original effective port area at the bore, at a length of 1.5 times the bore diameter 119.5mm.
Then cut the spigot roof at an angle of "X" degrees to achieve an opening of 100% of the original effective port area at a length of 2 times the bore diameter 159.5mm.
Is my thinking correct that all area changes are made by changing the angle of the duct and spigot roof, and the width of the complete setup is the same from the port to the end of the spigot?
If the above is correct is the transition from duct to spigot left sharp or radiused? If radiused, how much of a radius?
I can't seem to find much information with regards to the passages from the auxiliary exhausts. From the posted pictures, it looks like the passages exit the spigot at close to the horizontal centreline. Is the centreline of the spigot end the exit target or should these passages be ran at 25 degrees the same as the floor of the duct and spigot and exit wherever that puts them?
How is the sizing and the inward angle of the auxiliary passages determined? A semicircle equal to the height of the auxiliary port angled inward enough to still have the same semicircle at the end of the spigot?
Any and all help is appreciated.Hi Steve, I bundled a collection of tips and concepts, including some that deal with port and duct shapes. You should be able to download them here: https://jmp.sh/uXqkAr9

To All: please let me know if this works. It's my first attempt to make large files directly available.

[husaberg]

Hi Steve, I bundled a collection of tips and concepts, including some that deal with port and duct shapes. You should be able to download them here: https://jmp.sh/uXqkAr9

To All: please let me know if this works. It's my first attempt to make large files directly available.

It works Frits cheers, Next rainy day.

[jfn2]

Hi Steve, I bundled a collection of tips and concepts, including some that deal with port and duct shapes. You should be able to download them here: https://jmp.sh/uXqkAr9

To All: please let me know if this works. It's my first attempt to make large files directly available.

Works good for me. Thanks Frits.

[Frits Overmars]

Glad to hear it folks. Now I have an opportunity to pester you guys with more big files that I couldn't show until now.

Wanna see what HCCI really is? Here is a video, not an animation but the real deal, filmed inside firing engines, showing HCCI, spark ignition and diesel combustion modes. The huge difference in burn speed between the various modes should be an eye opener: https://jmp.sh/Fh8YLgc

And while I'm at it, you'll find my FOS Freeware collection here: https://jmp.sh/TFY6Q0k
I wrote these programs in the course of over four decades for my own personal use and I never bothered to make them user-friendly, so you may have to do some experimenting. The lot runs on DOS 6.2 or Windows 98 (I recommend Win98SE) so either dig up an old computer or use an emulator. On my Win7-laptop I use VMWare Player. I advise against DOSBox 0.74 because that is essentially a stripped-down version of DOS 5; it will run some of the programs, but not all of them.

By the way, everything that I make available on an open forum such as KiwiBiker or Pit-Lane, may be freely distributed. Happy Easter :D.
341564341565

[lohring]

Thanks , Frits, for that valuable information. Attached is my American English translation of your article on ignition timing. I hope i didn't loose any of your meaning or flavor.

Lohring Miller

PS I couldn't delete the first .pdf. The second is the complete article

[Frits Overmars]

Thanks , Frits, for that valuable information. Attached is my American English translation of your article on ignition timing. I hope i didn't loose any of your meaning or flavor.
Lohring MillerThank you so much Lohring.
I noticed that your translated version stops about halfway of the full German text. And modesty appears to have prevented you from adding your name as the English translator, which I think deserves mentioning. I'll be glad to add it.
Could you please mail your text in DOC- or ODT-format to fos@hetnet.nl, so I can fiddle a bit in the layout and attach the ignition graph?
Thanks again,
Frits

[lohring]

I also translated your Small Helmholtz course. Again, I hope I captured the meaning and flavor correctly.

Lohring Miller

[lohring]

OOPS I hope I did better on the Helmholtz translation. I'll fix the ignition article and send it to you.

Lohring Miller


Thank you so much Lohring.
I noticed that your translated version stops about halfway of the full German text. And modesty appears to have prevented you from adding your name as the English translator, which I think deserves mentioning. I'll be glad to add it.
Could you please mail your text in DOC- or ODT-format to fos@hetnet.nl, so I can fiddle a bit in the layout and attach the ignition graph?
Thanks again,
Frits

[Frits Overmars]

OOPS I hope I did better on the Helmholtz translation. I'll fix the ignition article and send it to you.That Helmholtz article is looking really good. But could you mail me its DOC- or ODT-version too? I'd need to adapt the German texts in the graphs and then insert the new graphs in your text.

[lohring]

I just sent both off in Microsoft Word. I hope that works.

Lohring Miller

[Frits Overmars]

Thanks Lohring, the Word-format should do fine.
It may be a while before I can react; the missus has treatened with lethal actions if I go near a computer during the Easter days.

[ken seeber]

Thanks Lohring, the Word-format should do fine.
It may be a while before I can react; the missus has treatened with lethal actions if I go near a computer during the Easter days.

Don't feel singled out Frits, it's a trait displayed by many a missus (or is it missae?). :msn-wink:

[lodgernz]

Don't feel singled out Frits, it's a trait displayed by many a missus (or is it missae?). :msn-wink:

Mogli?
.

[wobbly]

I must say that the so call " Wobbly " exhaust duct parameters are based on square bore/stroke high output engines and thus oversquare
dimensions will give excessive lengths.
Lifting the duct floor is only possible once the blowdown has been fully optimised with Aux ports right around to bore center and pin plugs fitted.
Even then I believe Jan only dyno tested up 3mm in a 54,5 stroke and that is as far as I have dared go.
The floor should exit perpindicular then form a ski jump slope downward, and flattening asap.
The roof should exit at 25* then form a radius , reducing in slope.
This shape tends to equalise the cross sectional area at the point where the side ducts enter the main.
I have started to think that maybe even attempting a convex roof and or duct floor shape is needed to reduce the area/colume even further.
Recently I have been testing much larger ( wider ) swooping Aux ducts , and this increases peak and overev power up to a point of diminishing returns
and then the midrange suffers.
But of course widening the side ducts increases the area just past the Aux septum ends and on down further to the exit point , making
this bigger than the 75% rule.
So further changes to reduce the duct volume need looking at now.

[peewee]

this ktm rad turned out to be the perfect size for what i needed (yes im going to use rubber isolater bushings). brackets are on and old nipples are cut off and plugged. just have to put a couple new nipples on

[jamathi]

I must say that the so call " Wobbly " exhaust duct parameters are based on square bore/stroke high output engines and thus oversquare
dimensions will give excessive lengths.
Lifting the duct floor is only possible once the blowdown has been fully optimised with Aux ports right around to bore center and pin plugs fitted.
Even then I believe Jan only dyno tested up 3mm in a 54,5 stroke and that is as far as I have dared go.
The floor should exit perpindicular then form a ski jump slope downward, and flattening asap.
The roof should exit at 25* then form a radius , reducing in slope.
This shape tends to equalise the cross sectional area at the point where the side ducts enter the main.
I have started to think that maybe even attempting a convex roof and or duct floor shape is needed to reduce the area/colume even further.
Recently I have been testing much larger ( wider ) swooping Aux ducts , and this increases peak and overev power up to a point of diminishing returns
and then the midrange suffers.
But of course widening the side ducts increases the area just past the Aux septum ends and on down further to the exit point , making
this bigger than the 75% rule.
So further changes to reduce the duct volume need looking at now.

Making the auxiliary ducts wider than 12mm made less power was my experience

[Frits Overmars]

I must say that the so call " Wobbly " exhaust duct parameters are based on square bore/stroke high output engines and thus oversquare dimensions will give excessive lengths. Lifting the duct floor is only possible once the blowdown has been fully optimised with Aux ports right around to bore center and pin plugs fitted.
Even then I believe Jan only dyno tested up 3mm in a 54,5 stroke and that is as far as I have dared go.Don't let those 3 mm frighten you Wob. Jan had cylinders cast with the exhaust floor more than 3 mm above BDC, but when he realised that he would be in retirement before he would be able to test those, he ground the floors down to the already-tested level before leaving the racing department for good, knowing very well that if these higher floors would have given a positive result after his farewell, some Italian would claim to have 'corrected the errors that Jan Thiel left behind'.

[jamathi]

Don't let those 3 mm frighten you Wob. Jan had cylinders cast with the exhaust floor more than 3 mm above BDC, but when he realised that he would be in retirement before he would be able to test those, he ground the floors down to the already-tested level before leaving the racing department for good, knowing very well that if these higher floors would have given a positive result after his farewell, some Italian would claim to have 'corrected the errors that Jan Thiel left behind'.

That is true Frits.
But I had 2 cylinders cast with the bottom of the exhaust as high as the transfers top.
The last 5 years all our exhaust ducts were CNC machined.
With many variations!
During the last year the exhaust bottom was 3mm above BDC.

[wobbly]

The 12mm wide Aux ducts is exactly where I ended up in my testing as well and that was easy to hand grind ,test , then digitise to
have 5 axis CNC machined.
Filling the floor with weld is a nightmare once the cylinder has been run ,and then the cost of a replate means I simply havnt had
a chance to experement yet.
But going higher sure looks like it is the go , as the wider Aux ducts need compensating for in the extra area change past the septum ends.

[peewee]

hey guys I was looking and I could easily make a simple four sided duct for the front of the rad with 1.5mm thick aluminum plate. each side would only be able to extend about 3" in front of the rad and theres a lot of tubing obstructions for the incoming air to deal with but I don't really see any downside to doing this. what do you guys think ? I found a article that says theres no need for the duct to expand any more than 7* as it goes from entrance to the rad cores. does this sound about right ? this isn't a road going bike but I figured some simple front ducting would be easy enough to make and it should do a bit better at directing some air to the cores, rather than leaving the rad with nothing at all. https://www.linkedin.com/pulse/air-ducts-down-earth-guide-motorsport-applications-willem-toet

one last question about the 7*. are they meaning each wall would expand 7* ? so basically the opening of the duct would be smaller than the rad cores because each wall is leaning in 7*

[TZ350]

I figured some simple front ducting would be easy enough to make and it should do a bit better at directing some air to the cores, rather than leaving the rad with nothing at all. https://www.linkedin.com/pulse/air-ducts-down-earth-guide-motorsport-applications-willem-toet .... basically the opening of the duct would be smaller than the rad cores because each wall is leaning in 7*

That is a rely interesting article.

I have posted some of it below.

Radiator cooling entries. With a fixed point of blockage (such as a radiator) you can increase the rate of expansion beyond the normal 7 degree limit as you approach the core (aerodynamic blockage) itself. It is a trick many aero people use in all sorts of applications. So use increasing expansion as you get close to the core of the radiator. It is a good strategy to do that in any case if you can. A radiator entry should be at least 20% of the area of the core for most motorsport applications. Of course this is influenced by the speed of the vehicle, the radiator area, heat rejection etc. but that’s a good starting point. If you go significantly bigger you typically pay the price of some drag.

Some more from the same author:- https://www.linkedin.com/today/posts/willemtoet1

[husaberg]

That is a rely interesting article.

I have posted some of it below.

Radiator cooling entries. With a fixed point of blockage (such as a radiator) you can increase the rate of expansion beyond the normal 7 degree limit as you approach the core (aerodynamic blockage) itself. It is a trick many aero people use in all sorts of applications. So use increasing expansion as you get close to the core of the radiator. It is a good strategy to do that in any case if you can. A radiator entry should be at least 20% of the area of the core for most motorsport applications. Of course this is influenced by the speed of the vehicle, the radiator area, heat rejection etc. but that’s a good starting point. If you go significantly bigger you typically pay the price of some drag.
The drag applies to physical size of the radiator as well.
Remember the louvers shutters on planes they controlled the openings so as they flew faster they made the openings smaller to cut down on drag. they had 6 positions on a Spitfire.
Also looks like it shut down the outlet and changed the angle of attack as well.
341597341598341599341600
Mustang was a bit different it was suposed to add thrust, i belive the Britten set up was very similar
https://en.wikipedia.org/wiki/Meredith_effect
https://www.quora.com/Would-the-P-38-Lightning-have-benefitted-from-a-radiator-set-up-like-the-P-51-which-added-a-small-amount-of-thrust-instead-of-drag-What-about-laminar-flow-wings
http://silencetwisterbuild.blogspot.com/2012/11/radiator-theory.html
341601
Peter Williams used to change the entry arrea on the JPS Norton with Daytona being the smallest.






Thoughtful Engineering Is A Powerful Source Of Conversation

By Kevin Cameron April 11, 2019
In 1973, Peter Williams brought to Daytona his evolving concept of what could be achieved in racing with the limited power of Norton’s pushrod parallel-twin 750. In conversation, what came through was his cheerful and strong belief that thoughtful engineering, as opposed to reliance upon tradition, could still improve the motorcycle significantly.

As an example, cooling air for his engine’s head and cylinders was controlled by choice of an orifice plate, installed in the wind-tunnel-developed fairing just ahead of the engine. On a high-speed track such as Daytona, the smallest orifice would be used, with larger ones for tracks on which average air velocity would be less. It is, he noted, more efficient to flow air around the motorcycle than to let it flow through it. This is why aircraft powered by piston engines had either radiator shutters for liquid-cooling or cowl flaps to adjust cooling airflow to the power being used. The old practice of leaving the whole front of the fairing open ahead of the engine turned the bike into a large drag-producing air scoop—more just a cover rather than streamlining. Peter admitted just the cooling air needed. With its sophisticated air management, Peter’s design was just as fast as our 750cc Kawasaki two-strokes.

The area of the fairing behind Peter’s front wheel was a completely non-intuitive flat surface, the veritable “barn door” perpendicular to airflow. Why? British aircraft in World War II equipped with arrays of radar dipoles would have lost a lot of top speed had a partial solution not been found; later airborne radars had steerable dish antennas inside of streamlined fiberglass fairings. The dipole arrays were therefore placed ahead of flat surfaces. Air, slowing as it piled up in front of such surfaces, generated less drag as it passed through the dipoles. The aerodynamically “nasty” exposed fork and front wheel of a racing motorcycle, looking just like a radar dipole array to oncoming airflow, was therefore treated in the same way. The flat surface behind the front wheel pushed a lump of low-velocity air ahead of itself, within which the wheel generated significantly less drag.
https://www.cycleworld.com/thoughtful-engineering-is-powerful-source-conversation

[peewee]

heres a few photo someone might find useful

[JanBros]

this ktm rad turned out to be the perfect size for what i needed (yes im going to use rubber isolater bushings). brackets are on and old nipples are cut off and plugged. just have to put a couple new nipples on

seems very small in size for a high power twin cylinder ?

[peewee]

seems very small in size for a high power twin cylinder ?

for drag racing i think it will be a good size

[polcat88]

I must say that the so call " Wobbly " exhaust duct parameters are based on square bore/stroke high output engines and thus oversquare
dimensions will give excessive lengths.
Lifting the duct floor is only possible once the blowdown has been fully optimised with Aux ports right around to bore center and pin plugs fitted.
Even then I believe Jan only dyno tested up 3mm in a 54,5 stroke and that is as far as I have dared go.
The floor should exit perpindicular then form a ski jump slope downward, and flattening asap.
The roof should exit at 25* then form a radius , reducing in slope.
This shape tends to equalise the cross sectional area at the point where the side ducts enter the main.
I have started to think that maybe even attempting a convex roof and or duct floor shape is needed to reduce the area/colume even further.
Recently I have been testing much larger ( wider ) swooping Aux ducts , and this increases peak and overev power up to a point of diminishing returns
and then the midrange suffers.
But of course widening the side ducts increases the area just past the Aux septum ends and on down further to the exit point , making
this bigger than the 75% rule.
So further changes to reduce the duct volume need looking at now.

Thanks, Wobbly. I don't believe anyone in the snowmobile world has taken the auxiliaries out as far as Jan and you have. So the best way forward in your opinion would be to develop the auxiliary exhaust before anything else or would at the least filling the exhaust duct floor and roof from round to the actual port shape with auxiliary tunnels with no reduction in duct area be worthwhile?

[TZ350]

.
341611 341612

I have been making some progress fitting the CVT reduction box and positioning the crankcase on the CVT NX4 project. A few alignment issues but it is all looking possible.

The front tire hitting the pipe under braking/cornering has often been a problem on other builds but this is the first time I have had to be aware of the tire possibly hitting the head...... :laugh:

341614

The crankcases halves are going to be mounted either side of the 12mm plate like I did in the original GP-NSR110.

The original GP-NSR110 was deliberately made with stupid amounts of crankcase volume and it worked well.

341613

And with a long RD400 rod and the original scooter crankshaft there is going to be insane amounts of crankcase volume in the new CVT engine. It will be interesting to see how that goes. Being rotary valve I might get away with it, in fact it may even show a performance benefit. If its a dud then I will convert it to 70cc (class rules) and turbocharge it and have lots of high crankcase pressurized mixture.

[peewee]

seems very small in size for a high power twin cylinder ?

heres how i look at it and maybe im wrong. ive seen people use bigger ones. also ive seen them use just a small aluminum water box. i guess it depends on packaging limitations, cost of a radiator vs small water box, how many passes you want to make before shutting down the engine to cool, etc etc. also theres small 4" spal fans, mini electric water pumps. so theres alot of different methods to choose. i want to first see how the engine reacts with radiator of 4.5" x 11" in size , simple ducting and crankshaft driven waterpump. maybe later i can add better cooling methods if needed. also i use methanol which is a bit different than petrol, as your aware im sure

[wobbly]

Polcat - I can confirm that simply extending the Aux ducts out thru the spigot to the header interface does nothing.
The combination of better blowdown flow is offset by the increase in duct volume ( and the exit area ratio ) to the point that
no power is gained.
TM did this 10 years or more ago , and the concept failed miserably.
Its only when I introduced the 75% area reduction concept that the huge increase in power became a reality for the 3 port design.

[Frits Overmars]

Thanks, Wobbly. I don't believe anyone in the snowmobile world has taken the auxiliaries out as far as Jan and you have. So the best way forward in your opinion would be to develop the auxiliary exhaust before anything else... When working on the auxiliary exhaust ports, keep this in mind Steve:
341615
You may vary the angle of maximum overlap by varying the piston pin height in the piston, so that the overlap occurs when the pressure difference between exhaust and transfer ports is minimal. But completely closing the piston skirt is preferable in any case.

[TZ350]

maybe later i can add better cooling methods if needed. also i use methanol which is a bit different than petrol,

I have very fond memories of Methanol.

I ran a race TR250R Suzuki fitted with air cooled RD250 and later RD350 cylinders running on a 50/50 methanol/acetone blend. The problem was not cooling but rather getting the engine warm enough to evaporate the fuel properly.

You can easily over cool a methanol two stroke engine with just the fuel alone. When that happens the mixture looks lean but adding more fuel only makes things worse. The trick is to worm the engine up by blending the fuel to something that takes less heat out of the motor.

Later I was involved with a TZ750 based TQ racer on methanol. The engine was fitted with one TZ350 cylinder block and one TZ250 cylinder block to meet class capacity rules. The class also called for air cooling so the trick was to discard all the water cooling stuff and cut big holes in the outer skin of the water jackets so air could circulate around the inner cylinders for air cooling plus air cooled cylinder heads. That and methanol was enough cooling for long races of 25 laps or so.

Your little radiator might be to big unless you are running a thermostat. Even then the motor may be over cooled by the methanol and you will need to blend something less cooling with it. For my air cooled RD engines I used acetone for blending because its latent heat of evaporation is less severe and it has a very high octane rating.

The proper "Exhaust Tuned Length" is considerably shorter for a methanol engine too. Calculations have to be based on the slower wave speed through the much cooler methanol fog.

[peewee]

Your little radiator might be to big unless you are running a thermostat. Even then the motor may be over cooled by the methanol and you will need to blend something less cooling with it. I used acetone because its latent heat of evaporation is less severe and it has a very high octane rating.

The proper "Exhaust Tuned Length" is considerably shorter for a methanol engine too. Calculations have to be based on the slower wave speed through the much cooler methanol fog.

ive got two different styles of thermostats i can try. one is a bypass type that i got from someone around here. flettner maybe?. the other is nonbypass from a ktm dirtbike. about the pipes. ive been in contact with arlen from led regarding drag pipes. once i send some photos and measurments of the chassis and cylinder configuration. hopefully do that this weekend

[TZ350]

.

I love that you are working with Methanol and are very interested in the results.

I forgot to mention the crank oil seals. With my acetone methanol mix I left the oil seals in a sample jar with some of the 50/50 mix. The Suzuki ones seemed fine but Yamaha ones with the Teflon lip swelled up. They went back to their normal shape if they were left out for a few days.

The 50/50 mix was also hard on the lining of the Suzuki rotary valve covers, it loosened the bonding glue holding the lining on. I now use Kawasaki covers that don't have the anti friction lining.

I never tested it but I would be suspicious of composite rotary valve blades and fiber glass or carbon fiber reed valve's, best to use metal blades if you have acetone in the mix. Also if you have a rubber tipped float needle then I would check what that looks like after soaking it for a while too.

[shnaggs]

Frits, in regards to your port exit angle calculator, what does ATN stand for?

[Frits Overmars]

ATN stands for Arctangent. It is the counterpart of the Tangent function.
Example:
the tangent of 25 degrees is 0,4663077: Tan(25)=0,4663077
the arctangent of 0,4663077 is 25 degrees: Atn(0,4663077)=25
You may find the arctangent mentioned here: https://en.wikipedia.org/wiki/arctangent (https://en.wikipedia.org/wiki/arctangent]) and in my Pisa-story:
341637

[wobbly]

THere is one intermediate step available brefore having to use using pin plugs.
The exit angle shape of the Aux duct rear wall can be made shallow, to reduce the cavity connecting to the pin.
This makes more power ( and is easy enough to tune ) than a non overlapping rear wall , with the optimum angle.

[peewee]

whats some of the ways people have used to plug the pin hole ? i really havent put much thought into it yet but i have no plans of using shallow rear aux walls:laugh:. i wonder if some cork thats 10-20mm shorter than the pin then cap the ends with high temp fipg like threebond. but maybe the superfast start and stop of the piston might cause it to compess and work loose

[Haufen]

THere is one intermediate step available brefore having to use using pin plugs.
The exit angle shape of the Aux duct rear wall can be made shallow, to reduce the cavity connecting to the pin.
This makes more power ( and is easy enough to tune ) than a non overlapping rear wall , with the optimum angle.

Thanks. Did you experience differences in jetting between those variants, e.g. the variant with the most short circuiting at the pin being the trickiest to jet?

[flyincat]

On the subject of Aux port connecting, and piston plugs. I'm curious about the mechanism of the plug. Does it work by volume reduction or by sealing? If it's a sealing mechanism, I have some questions about the shape. Frits shared a plug that, if I remember correct, had a spherical shape end. In the case of a spherical shape, with the same curvature radius as the piston skirt, the only good seal would be horizontally half way up the piston pin. This brings me to the next question. Would this type of plug work equally well in both pistons shown here? Note the dual pockets on the one piston would interfere with the horizontal seal halfway up the piston pin.



THere is one intermediate step available brefore having to use using pin plugs.
The exit angle shape of the Aux duct rear wall can be made shallow, to reduce the cavity connecting to the pin.
This makes more power ( and is easy enough to tune ) than a non overlapping rear wall , with the optimum angle.

341638341639

[wobbly]

Kentastic made me some plugs in Torlon that matched the piston curvature , and had a small plastic ball in a machined slot
to prevent rotation.These had the clip captured and ran a slightly shortened pin.
These worked very well , except for a slight lack of axial clearance , that eventually smeared them up the bore.
But later I tested a simple flat faced plug and had trouble detecting any real difference in power.
All 3 versions I sketched will jet slightly differently, but once you have a weather/jet history its not an issue.
Only when running a big Aux overlap with deep pockets and no plugs do you run into short circuiting affecting the jetting response.
In my application there must have been insufficient lube access from the back of the pin boss ( no vertical holes into the boss either )
as I had trouble with the pin ends overheating.
This may in fact have been why the expensive Pankle , welded flat ended pins were favoured at Aprilia.

[husaberg]

I have never really understood why pressing in bungs works for big ends but is forbooten for gudgeon pins.
I are not having much like finding information that calculated the stess on each but i think Bell or Jennings covered it?
341640341641341642341644341645
Anyone got any data?

closest i can find is this
http://www.nrb.com.tw/en/factory.html
Which shows a greater bearing load on the big end bearing?
341646
plus the crankpin is also pressed in surely thats a load in itself as well

[Frits Overmars]

On the subject of Aux port connecting, and piston plugs. I'm curious about the mechanism of the plug. Does it work by volume reduction or by sealing? If it's a sealing mechanism, I have some questions about the shape. Frits shared a plug that, if I remember correct, had a spherical shape end. In the case of a spherical shape, with the same curvature radius as the piston skirt, the only good seal would be horizontally half way up the piston pin.The plugs work by blocking the connection that would otherwise exist from the aux.exhaust ports via the gudgeon pin bore in the piston to the A-transfer ports.
A spherical plug is not the optimum solution from a blocking point of view, but it was the optimum that I could produce with the machinery at hand. Producing plugs with rotation-preventing protrusions would have required CNC tools. And the leakage past a spherical plug is limited. Below is the worst case, with a leak path 9 mm wide and 0,47 mm deep: a reduction of 88% compared to a plug-less situation.
341648

Below: the latest, spherical-capped, hideously expensive but moderately sealing Pankl pistonpin as used in the works Aprilias and my re-usable (save the environment:p) Torlon plug, the chamfered pin bore in the piston not being a good idea in either case.
341649341650

[41juergen]

I got my simple plugs laser welded which were CNC maschined with a radius matching the piston shape (incl. it's piston offset... :msn-wink: ),
the welding costs only 20 €...

341651341652

[lohring]

Mark Atkinson's piston design (https://www.youtube.com/watch?v=YEaE6BHyjzg)gets around this issue.

Lohring Miller

[Haufen]

I got my simple plugs laser welded which were CNC maschined with a radius matching the piston shape (incl. it's piston offset... :msn-wink: ),
the welding costs only 20 €...

341651341652

I like that, there is not much of a difference when comparing with a genuine RSA / APF Pin (other than the price - the pin is in the same region as the piston afaik)

341653

-----------

By the way, I want to part with my APF 2011 cylinder set (cylinder, head, piston, exhaust valve etc), any suggestions where stuff like this is best traded?

[polcat88]

The plugs work by blocking the connection that would otherwise exist from the aux.exhaust ports via the gudgeon pin bore in the piston to the A-transfer ports.
A spherical plug is not the optimum solution from a blocking point of view, but it was the optimum that I could produce with the machinery at hand. Producing plugs with rotation-preventing protrusions would have required CNC tools. And the leakage past a spherical plug is limited. Below is the worst case, with a leak path 9 mm wide and 0,47 mm deep: a reduction of 88% compared to a plug-less situation.
341648

Below: the latest, spherical-capped, hideously expensive but moderately sealing Pankl pistonpin as used in the works Aprilias and my re-usable (save the environment:p) Torlon plug, the chamfered pin bore in the piston not being a good idea in either case.
341649341650


Frits, or Wobbly do you recall which grade of Torlon was used?

[wobbly]

I used 4203 rod.
Mark is taking the screw top piston one step further after I wised him up to a patented reverse L ring design that traps the
vertical leg and prevents bulging into large unbridged ports.
Our man on Two Stroke Stuffing is on the same path.

[husaberg]

https://youtu.be/jfpwqqoPv1A
https://i0.wp.com/www.ipdparts.com/wp-content/uploads/2018/07/piston-3.png

[lohring]

That's a piston with very different design from an engine with a lot higher cylinder pressure. How many thousand hours was that engine run? The standards are a lot tougher than on a two stroke race engine runs less than 100 hours between overhauls. We'll see how a two piece piston works in a small two stroke. One problem is testing two ideas at once. It may be hard to decide if the piston or the new ring style is the problem.

Lohring Miller

[wobbly]

The piston plug idea is already well documented , the ring trapping idea has also been well tested - and then a patent applied for based on the result.
So both are a known entity, combining them will show all the advantages of no port linking plus the huge tuning leeway gained from removing
the limiting factor of running up against insufficient Blowdown STA.

[flyincat]

Wob, Frits, others...thanks for the pin plug refresher info! For the life of me I can't find a discussion I remember reading about port linking (short circuiting) affecting certain RPM's more than others. Are there certain RPM's that you can get away with port linking (no pin plug)? My thinking is for CVT application, where low and mid range only need enough power to get to the powerband RPM range without falling on it's face.

Would direct injection, or even boost port injection, negate the need for pin plugs?

[wobbly]

From my testing there is almost a linear effect of powerloss from port linking.
In the 125 I was testing the plugs gave around 2 Hp at 10,000 ( lowest used rpm ) and around 1 Hp at 13500 and above.
I imagine that this is a function simply of time/area of the " leak " decreasing as the rpm increases.
The only way changing the intake method would be effective against this issue is direct cylinder injection, you would think ,but even then you still
have exhaust gas pressure trying to get down the transfer ports.

[peewee]

i was thinking same. any negative affects of linking would decrease as revs go up simply because the time it has to link decreases