ESE's works engine tuner

[Norman]

Imagine it's a hot day, say 35deg outside. Out in the yard lies a steel crowbar and a wooden handled shovel; they've both been in the sun for hours so they are both around the same temperature. But you just know that the crowbar is going to heat your hands up a hell of a lot more than the wooden shovel handle which won't hurt at all. I think the coating might be like the wooden handle - very hot but with a low thermal mass and a relatively low capacity to transfer that heat.

I should also mention that any work involving a large crowbar is inadvisable regardless of the weather....


If you would use the Fire Brigade's water hose on the steel bar during the day I would think you can handle it as the wooden shovel. Conclusion: No ceramic duct coating, needs all the cooling possible, with coating the cooling of the duct becomes less critical, and also more cooling capacity available at other places, with addtional positive effects? Will be very interesting to get the final confirmation from the "B"-test.

[oldjohnno]

If you would use the Fire Brigade's water hose on the steel bar during the day I would think you can handle it as the wooden shovel. Conclusion: No ceramic duct coating, needs all the cooling possible, with coating the cooling of the duct becomes less critical, and also more cooling capacity available at other places, with addtional positive effects? Will be very interesting to get the final confirmation from the "B"-test.

I understand what you're saying but how cool does the duct wall have to be to transmit less heat into the gas than a much less thermally conductive and lighter (thermally) coating? I guess if we knew the thermal characteristics of the coating, the port wall and the gases it could be calculated or modeled.

[diesel62]

I understand what you're saying but how cool does the duct wall have to be to transmit less heat into the gas than a much less thermally conductive and lighter (thermally) coating? I guess if we knew the thermal characteristics of the coating, the port wall and the gases it could be calculated or modeled.
Will be interesting to see the results. I'm not sure a relatively short port wall and the mass and speed of the exhaust gas will actually see any temperature difference at all.

[wobbly]

I will be logging egt and deto level in acceleration testing at the same rate as the engine is run on track.
Its my opinion as well that a shorter duct ( thus longer header ) would indeed make the header temp react faster.
But is that what is needed.
As you exit the corner at well less than peak power rpm, a cooler pipe will for sure give a wider dynamic power range, and its thus my belief the duct should be longer
due to this effect.
I have already track tested this by in effect cooling the back of the spigot by allowing water right around the duct and up to the flange back face.
I also concurrently cut Aux ears right thru the spigot, so the drop in track time by 3/10s cannot be attributed to one or other of the changes directly.
The Aux ears did not affect low end power on the dyno at all, but on track the driver, and the datalogger said it hooked up and drove out noticeably quicker - as well
as the big increase in overev power the dyno showed conclusively.
The pic shows the ears, and the slots.The red line is the new duct exit being cast at the factory now for testing as well.

[Jannem]

That's an interesting question,

How are you going to test this? Under which conditions? Steady state? Dynamic? Laptimes? And which parameters of the engine do you plan to change during the comparison?

I suppose a very well cooled exhaust port transfers about 8 hp more heat into the coolant which should then raise an engine temperature of 40 deg to about 44 deg. So as a starting point, the engine with the well cooled exhaust has a disadvantage of about half a pony or so. The question is then, can you gain more than that by throwing advance and compression at it until the same level of deto is reached? Probably yes, but the engine might need a shorter pipe first. If you can also run leaner this should recover some of the exhaust heat.

Is it really desirable to have the pipe heat up as fast as possible? If the heat up characteristic matches the track and the gearing this could also give an advantage due to a wider dynamic powerband, couldn't it?

The more I think about it, the more parameters come to my mind. This seems like at least a full week of testing if planned and executed thoroughly. I am looking forward to the outcome!

Agree. With pipe tuned to stock port and focusing on the power below the curve, the pipe ought to be more out of tune with coated port. Heat loss to coolant is a power loss, but how do you turn the new conditions impacting several variables into advantage at desired rpm...

[wobbly]

My logic is that it will be a cumulative, but single cycle event.
Each time the port opens, hot gas will run over the ceramic surface and thus heat that - with no sink into the alloy and water behind.
Then, the reverse pulse will push air/fuel that has been affected by that surface temp back into the cylinder - on every revolution.
The variable of bulk water temp isnt an issue as every test starts at 45* and I have a PLC setup that keeps the temp within a 2* hysteresis range of that
during the dyno run.

[Jannem]

My logic is that it will be a cumulative, but single cycle event.
Each time the port opens, hot gas will run over the ceramic surface and thus heat that - with no sink into the alloy and water behind.
Then, the reverse pulse will push air/fuel that has been affected by that surface temp back into the cylinder - on every revolution.
The variable of bulk water temp isnt an issue as every test starts at 45* and I have a PLC setup that keeps the temp within a 2* hysteresis range of that
during the dyno run.

If the target rpm is below existing peak, the pipe (and bike gearing) is fixed, and even IF the intake charge would heat up less in the ex.duct because of the insulating properties (poor heat absorbtion) and low thermal mass of the coating, the out of tune pipe with raised ex. temp could hurt more that what would be the potential gain from the cooler charge. That's not even considering what an impact pipe heat up speed in transient situation would do.

Looking forward hearing what you'll find out.

[wobbly]

I had a midnight thought about the Ex duct coatings effect.
I remembered back to testing pistons coated with ceramic, the end gases in the squish band detonated instantly.
Thus it must be the boundary layer formed above the coating that is way hotter.
In the pistons case, this transferred enough heat into the trapped combustion mixture to cause formation of free radicals and then deto.
I can see in the ducts case, the boundary layer having plenty of thermal mass to enable overheating of the returning over-scavenged air/fuel charge.
We shall see.

[jamathi]

I will be logging egt and deto level in acceleration testing at the same rate as the engine is run on track.
Its my opinion as well that a shorter duct ( thus longer header ) would indeed make the header temp react faster.
But is that what is needed.
As you exit the corner at well less than peak power rpm, a cooler pipe will for sure give a wider dynamic power range, and its thus my belief the duct should be longer
due to this effect.
I have already track tested this by in effect cooling the back of the spigot by allowing water right around the duct and up to the flange back face.
I also concurrently cut Aux ears right thru the spigot, so the drop in track time by 3/10s cannot be attributed to one or other of the changes directly.
The Aux ears did not affect low end power on the dyno at all, but on track the driver, and the datalogger said it hooked up and drove out noticeably quicker - as well
as the big increase in overev power the dyno showed conclusively.
The pic shows the ears, and the slots.The red line is the new duct exit being cast at the factory now for testing as well.

We made a shorter duct + longer header at Aprilia around the time Roland worked there.
It was done trying to lower the water temperature.
It proved completely useless, on the dyno and on track.....
I also belief that the duct should be longer!
Probably a case of usual 'kart-madness' I think.
A lot of people in karting seem to suffer this 'sickness'
Constantly changing things that are already known for years
I still wonder why a ceramic coating was not tried the next day you were at TM.....
After trying your water-cooled flange first!

When I made my first 'ears', in 1996 I think it was, I first tested the cylinder without.
Took it off, had it CNC machined and saw the big improvement, 1 hour later.
And without losing anything anywhere!
After that I never looked back....

[wobbly]

I think the big issue was ( and will be for a while yet ) that even though I have the CAD files and are about to do the pipe testing for the
new homologation TM engine,Franco made it very clear i was not getting into the R&D or dyno testing areas.
He has many secrets, and said that my " micrometer eyes " would know all of them in no time.
No one and I mean NO one, gets to look inside the 10 factory sponsored TM kart engines at any time - on or off the track.
It surprised the hell out of me when he sent me a pic of a new CNC head insert with MY secret design - so maybe the ceramic test has already been done.
For sure no one outside the factory would find out about that anyway.
I just have to hope that I can build enough trust, once the pipe program is completed.

[Jannem]

I had a midnight thought about the Ex duct coatings effect.
I remembered back to testing pistons coated with ceramic, the end gases in the squish band detonated instantly.
Thus it must be the boundary layer formed above the coating that is way hotter.
In the pistons case, this transferred enough heat into the trapped combustion mixture to cause formation of free radicals and then deto.
I can see in the ducts case, the boundary layer having plenty of thermal mass to enable overheating of the returning over-scavenged air/fuel charge.
We shall see.

I definitely don't claim to know better, but it's an interesting thought exercise. Alternative cause for deto could be simply elevated combustion temperature after ignition, because heat loss path via piston top was blocked. That's a big part of the surface area of the combustion space and ought to have a noticeable effect.

[Peter1962]

I think the big issue was ( and will be for a while yet ) that even though I have the CAD files and are about to do the pipe testing for the
new homologation TM engine,Franco made it very clear i was not getting into the R&D or dyno testing areas.
He has many secrets, and said that my " micrometer eyes " would know all of them in no time.
No one and I mean NO one, gets to look inside the 10 factory sponsored TM kart engines at any time - on or off the track.
It surprised the hell out of me when he sent me a pic of a new CNC head insert with MY secret design - so maybe the ceramic test has already been done.
For sure no one outside the factory would find out about that anyway.
I just have to hope that I can build enough trust, once the pipe program is completed.

wobbly, have you been able to convince them to alter the design of their exhaust duct, or was that not open for debate ?

[jonny quest]

What's the largest carb size tried on the RSA125?

You settled on a 41mm, right?

What were the negative effects of carb size above and below the carb size used?

I have a hunch a smaller carb caused worse detonation in the mid range

[ken seeber]

Talking of exhaust mfg, here’s something of interest. It’s about a place in Italy (Elto Racing) that mfg the multi piece KZ style exhausts. https://www.youtube.com/watch?v=Da-g7LTsGWM

Have a look at this one and you can see they do a lot of exhausts for lots of customers, inc TM. http://www.eltoexhaust.com/en/

As to the rolling, where Elto use the 2 roll principle (steel top roll and urethane bottom roll), this joint supplies them. https://www.acrotechinc.com/art-of-bending/ A shitload better than mucking about with the 3 rolls and gets the rolling very close to the edge.

Maybe there is an opportunity for you ingenious & recourceful kiwi guys, other than sending up satellites. Over here in Oz, there is a saying in the karting industry: ”You can make a small fortune out of karting, as long as you start out with a big one”. :laugh:

[Frits Overmars]

What's the largest carb size tried on the RSA125? You settled on a 41mm, right?
What were the negative effects of carb size above and below the carb size used?
I have a hunch a smaller carb caused worse detonation in the mid rangeThe RSA was run with 42 mm and 43 mm carbs. Most riders prefered 42 mm because they felt it was more responsive to rider input.
Worse detonation in some rpm range because of a carburetter swap will probably stem from a too-lean mixture in that range. I do not think there is a direct correlation between this leanness and the carb diameter. In any case, there shouldn't be.

[Patrikh]

....... The throttle body MAP sensor is connected to the exhaust port and samples the pressure during blowdown. I’ve set up a 2nd fuel table in the ECU with a multiplier for when the pressure is above a threshold, corresponding to the cylinder firing. When the exhaust pressure is high, the main fuel table is unchanged, when low, it is reduced by 50% (will need to be dialled in for various RPM, but seems to work so far). The main fuel table is tuned with the wideband when the motor is firing, then extrapolated into the non-firing low throttle/overrun area. On closing the throttle, once the motor stops firing, fuel flow drops to match the airflow, so the motor doesn’t flood. On opening the throttle, the mixture is correct to initiate firing, then after the first fire fuel flow goes back to the main table value.

I think with some tuning I should be able to get the transition pretty much seamless. At the moment I'm working on getting the fuel table just right around the transition area, then I'll work on the switch threshold and multiplier values. That said, it's pretty decent already, but I'm a perfectionist.

Nathan


Hi Nathan!

I'm running an almost identical setup as you but on an 82cc engine, and i'm experiencing the same thing as you. Since it is a pure dragrace machine i thought i would not need the low throttle leaning, but i feel it would be nice to be able to ride it back from a run without going wide open throttle.
I have a map sensor now that i use just for baro correction at start up, do you use youre exhaust map sensor for baro correction? I was thinking if i would need another one or could use my existent one for both purposes.
Do you have any advice for the setup in Microsquirt or any other dos and don'ts?

Regards
Patrik

[RSC]

I was reading an article the other day that said one of the reasons why Honda opted for reeds for the NS500 was that it was easier to start,and judging from race starts I've seen that seems to be the case.So is a Reed valve 2 stroke fundamentally easier to start than a disc valve ,and why?

[peewee]

Alternative cause for deto could be simply elevated combustion temperature after ignition, because heat loss path via piston top was blocked.

thats what i was wondering. what happens to the heat if it cant go to the piston top, to the rings, to the bore walls ?

[wobbly]

2Ts are hateful things but do in the end respond to some sort of logic.
The ceramic coated piston was a disaster,but change the coating so that only the dome is insulated,and the squish area is left stock - then the deto instantly goes away.
One has to assume that the heat that isnt absorbed by the piston has to go either into the combustion gas, or a % of it is transferred into the water via the insert.
When I tested this the egt did rise,about 1/2 a jet size,so not really significant,but if you coat the combustion chamber ( not the squish area ) the temp rises another
whole jet size and the pipe then reved on a worthwhile amount.
As it turns out, i prefer now to mirror polish the piston ( much cheaper than ceramic ) and that works even better.
But you have to keep on cleaning it as oil burns onto the surface.
The coating in the chamber is a real "hidden trick " and doesnt cost much at all.
It increases the combustion gas heat retention and the water temp drops, a win win.

Have a think about the process and what is needed by different parts of the enclosed combustion space.
We want to keep heat out of the piston and in the gas - so polish the piston so it reflects the heat back.
We want to keep heat out of the water - coat the chamber.
We want to effectively cool the plug body - get water right up to the threads.
We want to keep the squish area boundary layer and thus the trapped end gases cool - you work it out, I have but aint telling.

Re the TM Ex duct - I have the cylinder CAD file so I remodeled the duct,reducing the height and added the ears all the way down the side right thru the spigot to the header.
The exit area is smaller again than the C model, and as per usual it made best power in the sim at 75% of the effective total Ex port area.
Franco has the file,and has promised to make the special sand cores for a cylinder in the next manufacturing batch - " just to make me happy ".
As Jan said,I think he will be surprised, but for me it enables a bigger scope of new pipe design critera with alot more front side power and overev capability.

[diesel62]

2Ts are hateful things but do in the end respond to some sort of logic.
The ceramic coated piston was a disaster,but change the coating so that only the dome is insulated,and the squish area is left stock - then the deto instantly goes away.
One has to assume that the heat that isnt absorbed by the piston has to go either into the combustion gas, or a % of it is transferred into the water via the insert.
When I tested this the egt did rise,about 1/2 a jet size,so not really significant,but if you coat the combustion chamber ( not the squish area ) the temp rises another
whole jet size and the pipe then reved on a worthwhile amount.
As it turns out, i prefer now to mirror polish the piston ( much cheaper than ceramic ) and that works even better.
But you have to keep on cleaning it as oil burns onto the surface.
The coating in the chamber is a real "hidden trick " and doesnt cost much at all.
It increases the combustion gas heat retention and the water temp drops, a win win.

Have a think about the process and what is needed by different parts of the enclosed combustion space.
We want to keep heat out of the piston and in the gas - so polish the piston so it reflects the heat back.
We want to keep heat out of the water - coat the chamber.
We want to effectively cool the plug body - get water right up to the threads.
We want to keep the squish area boundary layer and thus the trapped end gases cool - you work it out, I have but aint telling.

Re the TM Ex duct - I have the cylinder CAD file so I remodeled the duct,reducing the height and added the ears all the way down the side right thru the spigot to the header.
The exit area is smaller again than the C model, and as per usual it made best power in the sim at 75% of the effective total Ex port area.
Franco has the file,and has promised to make the special sand cores for a cylinder in the next manufacturing batch - " just to make me happy ".
As Jan said,I think he will be surprised, but for me it enables a bigger scope of new pipe design critera with alot more front side power and overev capability.
On that note does a skirt coated moly piston slow the heat transfer between piston and barrel.

Sent from my SM-G900F using Tapatalk

[wobbly]

[QUOTE=diesel62;1131051284]On that note does a skirt coated moly piston slow the heat transfer between piston and barrel.

I dont know how you would measure that, but I have never seen any evidence of piston overheating on coated pistons.
All the papers I have seen on the subject state that the vast majority of heat transfer is thru the ring to the bore.
And in jetski racing with very big overbores I know of one famous tuner who " fixed " piston overheating issues by simply adding a second ring.

[diesel62]

[QUOTE=diesel62;1131051284]On that note does a skirt coated moly piston slow the heat transfer between piston and barrel.

I dont know how you would measure that, but I have never seen any evidence of piston overheating on coated pistons.
All the papers I have seen on the subject state that the vast majority of heat transfer is thru the ring to the bore.
And in jetski racing with very big overbores I know of one famous tuner who " fixed " piston overheating issues by simply adding a second ring.
Thanks

Sent from my SM-G900F using Tapatalk

[Nath88]

Hi Nathan!

I'm running an almost identical setup as you but on an 82cc engine, and i'm experiencing the same thing as you. Since it is a pure dragrace machine i thought i would not need the low throttle leaning, but i feel it would be nice to be able to ride it back from a run without going wide open throttle.
I have a map sensor now that i use just for baro correction at start up, do you use youre exhaust map sensor for baro correction? I was thinking if i would need another one or could use my existent one for both purposes.
Do you have any advice for the setup in Microsquirt or any other dos and don'ts?

Regards
Patrik

I use a separate sensor, you could use the same sensor, but if you have a power interruption with the engine running the baro correction value will then be incorrect, might go lean, might go rich. You can just get any sensor, then calibrate it from the main sensor.

Microsquirt set up is pretty self explanatory with MSextra firmware, I haven't had any issues with it so far.
What are you using as a crank trigger? Port injection? How many injectors?

I should probably be using 2 injectors, or a bigger injector at least. 75% injector duty cycle, not enough time for the injector to close fully at 10,000rpm.

[F5 Dave]

I was reading an article the other day that said one of the reasons why Honda opted for reeds for the NS500 was that it was easier to start,and judging from race starts I've seen that seems to be the case.So is a Reed valve 2 stroke fundamentally easier to start than a disc valve ,and why?

So what year did they move from push starts to clutch starts? Certainly relevant to NS500. I remember reading about the diminutive Paul Lewis (angry ant or summit like that) struggling to start the RV RGB .

I have limited experience but have tired myself out pushing a Rotax 256 bike that would start real nice with 2 people and not so flash with just one inexperienced Muppet (me).

[lodgernz]

So what year did they move from push starts to clutch starts?

About 1980 in NZ I think, maybe a year or two earlier. I always had to push-start my CR125 road racer, but I don't ever remember pushing my RD250LC.

[Grumph]

About 1980 in NZ I think, maybe a year or two earlier. I always had to push-start my CR125 road racer, but I don't ever remember pushing my RD250LC.

Canterbury club changed in 71/72 season. Pretty sure the GP was clutch start that year too. But canty were in advance of most...We had guys coming back from the US who were converts.

[Patrikh]

I use a separate sensor, you could use the same sensor, but if you have a power interruption with the engine running the baro correction value will then be incorrect, might go lean, might go rich. You can just get any sensor, then calibrate it from the main sensor.

Microsquirt set up is pretty self explanatory with MSextra firmware, I haven't had any issues with it so far.
What are you using as a crank trigger? Port injection? How many injectors?

I should probably be using 2 injectors, or a bigger injector at least. 75% injector duty cycle, not enough time for the injector to close fully at 10,000rpm.

I run a homemade 24-1 trigger with a VR-sensor. It is a modified 38mm throttle from a gsxr600 or something, with one port injector and another one upstreams pointing straight down the funnel.
With them fully staged I think there where like 40-50% duty on both, so i would recomend two injectors!

[RSC]

So what year did they move from push starts to clutch starts? Certainly relevant to NS500. I remember reading about the diminutive Paul Lewis (angry ant or summit like that) struggling to start the RV RGB .

I have limited experience but have tired myself out pushing a Rotax 256 bike that would start real nice with 2 people and not so flash with just one inexperienced Muppet (me).

I think 1983 was the last year that they push started the bikes.

A patent from Nomura here
(https://www.google.ch/patents/US3687118) suggests that reed valve engines were hard to start as well,but they retarded the intake port open periods and they took advantage of the added flow of the boost ports to overcome the problem.So why would a disc valve be any different?

[husaberg]

So what year did they move from push starts to clutch starts? Certainly relevant to NS500. I remember reading about the diminutive Paul Lewis (angry ant or summit like that) struggling to start the RV RGB .

I have limited experience but have tired myself out pushing a Rotax 256 bike that would start real nice with 2 people and not so flash with just one inexperienced Muppet (me).
That might be because the rotax 256 also fires both pistons at the same time. I would wager a reed valved bike with a similar set up would be hard to start as well.

I think 1983 was the last year that they push started the bikes.

A patent from Nomura here
(https://www.google.ch/patents/US3687118) suggests that reed valve engines were hard to start as well,but they retarded the intake port open periods and they took advantage of the added flow of the boost ports to overcome the problem.So why would a disc valve be any different?
i have it in something i posted previously (that i will find in a minute) but it was in the NSR era arround 87 ish i think.
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130224117#post1130224117
(Yes 87 was the first year third attachment)
The use of reeds instead of discs in the Japanese bikes was more likely because for them they could cross pollenate with the MX bikes tech.
the reed at first allowed a more user friendly power delivery as evidenced by the superiority on the 500's plus also up to the mid to late 90's on bumpy and tight tracks, even on the 125's and 250's.

[RSC]

i have it in something i posted previously (that i will find in a minute) but it was in the NSR era arround 87 ish i think.
https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130224117#post1130224117
(Yes 87 was the first year third attachment)
The use of reeds instead of discs in the Japanese bikes was more likely because for them they could cross pollenate with the MX bikes tech.
the reed at first allowed a more user friendly power delivery as evidenced by the superiority on the 500's plus also up to the mid to late 90's on bumpy and tight tracks, even on the 125's and 250's.

That is of course true.The only experience Honda had with 2 strokes stemmed from reed valved MX bikes, Miyakoshi himself was project leader in the development of many of these.So of course they would use tech they were familiar with,given that unlike with the NR,this time they had to succeed quickly.

Still,it would be interesting to know if reed valved 2 strokes are fundamentally easier to start than disc valved.

[F5 Dave]

I've only had 3 RV bikes and 2 were road spec discs, but every reed valver was like 2 steps and drop the clutch, at least when hot.

[husaberg]

That is of course true.The only experience Honda had with 2 strokes stemmed from reed valved MX bikes, Miyakoshi himself was project leader in the development of many of these.So of course they would use tech they were familiar with,given that unlike with the NR,this time they had to succeed quickly.

Still,it would be interesting to know if reed valved 2 strokes are fundamentally easier to start than disc valved.

Honda did arround that period have the two disc valved bikes the 1981 RC125 and the RS125T.
http://i155.photobucket.com/albums/s297/Lozza85_2007/30_1024.jpg
I do have something written about the NSRs that i have neever posted that suggests the engine characterstic of theese two bikes were the reason they stayed reed.
prior to the introduction of the big bang motor the engine design was through open to anyone at HRC.
Four options were chosen, two were developed, One option was the big bang, the other i believe was a similar set up to the Swiss auto.
the other two i have no idea about.

It should be noted that Kawaski KR250 were also pretty successful also suzuki and yamaha did a lot of Disc valve bikes from the 60's right up to the mid 80's.

re the starting i have no idea, but they are both easier to start than a simliar output piston port.

[oldjohnno]

This is what Kevin Cameron had to say in "The Grand Prix Motorcycle"

Another advantage of the NS was that its reed valves made it a much quicker push-starter than any disc-valve engine. The disc-valve engine's piston was only 10mm into its 54mm up-stroke when the intake opened, creating very little "pop", or suction signal, with which to start fuel flowing in the carburetors. By contrast, the stiffness of the reeds - which has to be high enough to enable them to keep up with the engine at 11,000rpm - prevents opening until a stronger vacuum has been pulled on the crankcase. When the more sudden pop from this hits the carburetors, they deliver fuel promptly.

[husaberg]

This is what Kevin Cameron had to say in "The Grand Prix Motorcycle"

Another advantage of the NS was that its reed valves made it a much quicker push-starter than any disc-valve engine. The disc-valve engine's piston was only 10mm into its 54mm up-stroke when the intake opened, creating very little "pop", or suction signal, with which to start fuel flowing in the carburetors. By contrast, the stiffness of the reeds - which has to be high enough to enable them to keep up with the engine at 11,000rpm - prevents opening until a stronger vacuum has been pulled on the crankcase. When the more sudden pop from this hits the carburetors, they deliver fuel promptly.

Sometimes the reeds signal works far too well, which is why cagiva had to put in spacers under the reeds so the reeds never completely closed.

[Frits Overmars]

The only experience Honda had with 2 strokes stemmed from reed valved MX bikes.This is an MX bike. It's rotary. And it says Honda. Categorical statements are always risky...
331416


Sometimes the reeds signal works far too well, which is why cagiva had to put in spacers under the reeds so the reeds never completely closed.Reeds need a pressure differential before they will open, and the bulk of that differential is provided by the suction effect of the exhaust system.
When you close the throttle, combustion stops, all pipe effects stop, and the reeds stay almost closed. When you open the throttle again, exiting a corner, nothing happens because there is not enough igniteable mixture in the cylinder. So you open the throttle a bit further, and a bit further still, and at some time the cylinder contents are igniteable again. So combustion starts, the pipe chimes in and it's two-stroke business as usual. But now your throttle is wide open and the next thing you'll experience is a highside.
Cagiva put spacers under the reeds in order to make sure that they never completely closed. It cost power but it helped lap times and saved bikes and riders.
The spacers killed the 'pop' that Kevin Cameron mentioned, so carburation became less than responsive, which inspired Cagiva to experiment with fuel injection.

[husaberg]

This is an MX bike. It's rotary. And it says Honda. Categorical statements are always risky...
331416

Reeds need a pressure differential before they will open, and the bulk of that differential is provided by the suction effect of the exhaust system.
When you close the throttle, combustion stops, all pipe effects stop, and the reeds stay almost closed. When you open the throttle again, exiting a corner, nothing happens because there is not enough igniteable mixture in the cylinder. So you open the throttle a bit further, and a bit further still, and at some time the cylinder contents are igniteable again. So combustion starts, the pipe chimes in and it's two-stroke business as usual. But now your throttle is wide open and the next thing you'll experience is a highside.
Cagiva put spacers under the reeds in order to make sure that they never completely closed. It cost power but it helped lap times and saved bikes and riders.
The spacers killed the 'pop' that Kevin Cameron mentioned, so carburation became less than responsive, which inspired Cagiva to experiment with fuel injection.
They had the similar powered 125 gp bike as well. I was also told they also had a tandem twin that they played with. but i have never seen a picture of it.
Erv Kanemoto was once told by an HRC technican that he was never to mess with the cutaway shape on the NSR, when he asked why? he was told that the shape had taken 6 solid months of work to get right.

[Frits Overmars]

Erv Kanemoto was told by an HRC technician that he was never to mess with the cutaway shape on the NSR, when he asked why? he was told that the shape had taken 6 solid months of work to get right.I bet the next thing Erv did was try a different cutaway. I know I would have. Getting a good advice is fine, but one also wants to know the background :rolleyes:.

[husaberg]

I bet the next thing Erv did was try a different cutaway. I know I would have. Getting a good advice is fine, but one also wants to know the background :rolleyes:.

imagine going home to the mrs and answering that yes you were working on the cutaway for 180 days in a row:killingme

[2T Institute]

Talking of exhaust mfg, here’s something of interest. It’s about a place in Italy (Elto Racing) that mfg the multi piece KZ style exhausts. https://www.youtube.com/watch?v=Da-g7LTsGWM

Have a look at this one and you can see they do a lot of exhausts for lots of customers, inc TM. http://www.eltoexhaust.com/en/

As to the rolling, where Elto use the 2 roll principle (steel top roll and urethane bottom roll), this joint supplies them. https://www.acrotechinc.com/art-of-bending/ A shitload better than mucking about with the 3 rolls and gets the rolling very close to the edge.

Maybe there is an opportunity for you ingenious & recourceful kiwi guys, other than sending up satellites. Over here in Oz, there is a saying in the karting industry: ”You can make a small fortune out of karting, as long as you start out with a big one”. :laugh:

:niceone: great stuff Ken

[ken seeber]

Cool Lozza. :laugh:


I do know in karting that reeds start (& idle) so much easier than piston ports, as Husa has pointed out. At starting speed, effectively due to their passive shutting off, reeds do offer a positive displacement principle. A piston port, at very low rpms will provide a net inlet flow of zero.

Dunno about rotary valves, but must be a function of the crank angle position at the time of closure. Fletto’s variable timing disc valve system could help here, although I can’t remember whether it controlled opening or closing.

[Jannem]

2Ts are hateful things but do in the end respond to some sort of logic.
The ceramic coated piston was a disaster,but change the coating so that only the dome is insulated,and the squish area is left stock - then the deto instantly goes away.
One has to assume that the heat that isnt absorbed by the piston has to go either into the combustion gas, or a % of it is transferred into the water via the insert.
When I tested this the egt did rise,about 1/2 a jet size,so not really significant,but if you coat the combustion chamber ( not the squish area ) the temp rises another
whole jet size and the pipe then reved on a worthwhile amount.
As it turns out, i prefer now to mirror polish the piston ( much cheaper than ceramic ) and that works even better.
But you have to keep on cleaning it as oil burns onto the surface.
The coating in the chamber is a real "hidden trick " and doesnt cost much at all.
It increases the combustion gas heat retention and the water temp drops, a win win.

Have a think about the process and what is needed by different parts of the enclosed combustion space.
We want to keep heat out of the piston and in the gas - so polish the piston so it reflects the heat back.
We want to keep heat out of the water - coat the chamber.
We want to effectively cool the plug body - get water right up to the threads.
We want to keep the squish area boundary layer and thus the trapped end gases cool - you work it out, I have but aint telling.

Re the TM Ex duct - I have the cylinder CAD file so I remodeled the duct,reducing the height and added the ears all the way down the side right thru the spigot to the header.
The exit area is smaller again than the C model, and as per usual it made best power in the sim at 75% of the effective total Ex port area.
Franco has the file,and has promised to make the special sand cores for a cylinder in the next manufacturing batch - " just to make me happy ".
As Jan said,I think he will be surprised, but for me it enables a bigger scope of new pipe design critera with alot more front side power and overev capability.

Thank You for sharing this. :) Still lot to be learned...

[breezy]

Frits, wobbly,Jan,

is their any kind of rule of thumb regarding the compression pressures above and below the piston on a two stroke engine which are deemed relevant for two stroke engine rpm?

[wobbly]

Peak combustion pressure exceeds 80 Bar, peak case pressure is under 0.5 Bar.

[jonny quest]

Why would a shorter exhaust duct hurt power? Is it because the cast shape can be more organic?

[wobbly]

Why would a shorter exhaust duct hurt power? Is it because the cast shape can be more organic?

A short duct allows more of the over-scavenged air/fuel mixture to be subjected to the uncooled spigot/header surface.
This heated mixture is than shoved back in past the closing port.
Any heat added to the trapped combustion gases within the cylinder reduces its density and directly affects power.
Of more concern is that if its overheated enough, it causes detonation.
As Jan stated, they tried a shorter duct and longer header at Aprilia and it was useless on the dyno and the track.
He also stopped water from accessing the bottom of the duct, and that lost power and detoed like hell as well.

[JdG]

On the insulation of the exhaust duct:

If the duct were to be perfectly insulated on the inside, there would be no heat transfer to or from the gas in the duct. The inside wall of the duct would immediately assume the same temperature as the gas inside the duct, whether the gas is hot or cold without any heat being transferred.

The interesting thing now is: Is the fresh mixture that has to be pushed back into the cylinder hotter or colder than the exhaust duct wall temperature when it enters this duct coming from inside the cylinder. The fresh mixture that scavenges the cylinder picks up heat on the way before it enters the exhaust duct. If this fresh mixture is actually cooled inside the (water cooled) duct, I assume insulating the exhaust duct would have a negative effect. If the cooling of the exhaust duct is necessary to prevent the fresh mixture from heating up, then insulating the exhaust duct would have a positive effect.

I'm very curious about the results of the tests.

Regards.

[Frits Overmars]

is their any kind of rule of thumb regarding the compression pressures above and below the piston on a two stroke engine which are deemed relevant for two stroke engine rpm?Not so much a rule of thumb, but basic logic: you want as much fresh mixture as possible in the cylinder, so you want the pressure in the cylinder at exhaust closure to be as high as possible. But then you want the pressure rise above the piston as low as possible as long as the piston is rising, which means a low secondary compression ratio, followed by a cylinder pressure as high as possible, as soon as the piston is descending. That means: late ignition and fast burning.
In the Aprilia RSA the cylinder pressure at exhaust closure is about 2,6 bar. At TDC this pressure exceeds 80 bar as Wobbly mentioned, and 20° later it exceeds 120 bar. At exhaust opening it still exceeds 11 bar, which gives a nice bang for the exhaust pipe to work with.

Re the pressure under the piston: you want to inhale as much mixture as possible, so you want a low pressure in the crankcase during the inlet phase, followed by as much pressure rise as you can get when the transfer ports open. But the crankcase is a mediocre pump at best. Fortunately the exhaust pipe takes care of our wish list.
To answer your initial question: all of the above should be independent of engine rpm. Hence the variable ignition and exhaust timing tricks.


On the insulation of the exhaust duct: If the duct were to be perfectly insulated on the inside, there would be no heat transfer to or from the gas in the duct. The inside wall of the duct would immediately assume the same temperature as the gas inside the duct, whether the gas is hot or cold without any heat being transferred.That would be true if the insulation layer had zero thermal mass. I haven't discovered such a stuff yet and I don't think it will happen in my lifetime.
Hence the practice of mirror-polishing the piston crown: It does not block heat, it merely reflects it, and there is zero time delay: as soon as the heat source is gone, there is no more heat. So cool mixture is not affected by previous hot gases. At least in theory :D.

[SwePatrick]

Testweekend writeup ;)

My normal driver was sick so i called in an another friend, which sadly enough weights a lot more.
But, unimportant as i wanted a hard shakedown to test quality of engine and chassi.

We managed to run 39 runs with only one failure, the pipe cracked.
This was very good as i could concentrate on tuning.
Chassi worked really well, driver said it could easily handle twice the power.

Engine delivered same performance run after run, but after about 20 runs it started emptying the floatbowl, as i adjusted the trapspeed rised, and when all my trick up my sleeve was gone i used pipepressure to load fueltank with pressure.

Then trapspeed went up again, but weather had changed, different tents in the depot started to blow away.
It was hard wind straight against us when trying to get more topspeed.

The bike were sadly enough very high geared so it was hard to get it off the line.
Best 60ft was 1.89, i want 1.6x at least.
So if i gear it to get faster off the line i will lose trapspeed as is.
To get rid of this problem i have ordered a 2004 kx250 gearbox, it has taller gearing on 4th and 5th.
With that i can gear it faster off the line and still get high trapspeeds.

The clutch got huge amount of beating, and it just asked for more.
Carbon discs are the 'thing' it seems.

Only thing i adjusted was floaterlevel and the airbleed for lowspeed pilotjet.
Ohh,, one more thing..
I had to adjust the chain, brand new and it stretched some i guess, i´m running a small '428' chain ;)

A small clip:

https://www.facebook.com/patrick.wetterskog/videos/10155044821949475/

[breezy]

Peak combustion pressure exceeds 80 Bar, peak case pressure is under 0.5 Bar.

ok thanks .. would it be true to say that after combustion the speed of the descending piston through the first 180 * to btdc is faster than the next 180* back up to tdc due to no no real pressure being exerted from below the piston to increase its speed with only inertia of the crank in play?

[breezy]

"Re the pressure under the piston: you want to inhale as much mixture as possible, so you want a low pressure in the crankcase during the inlet phase, followed by as much pressure rise as you can get when the transfer ports open. But the crankcase is a mediocre pump at best. Fortunately the exhaust pipe takes care of our wish list.
To answer your initial question: all of the above should be independent of engine rpm. Hence the variable ignition and exhaust timing tricks"

oK Frits, thanks.Do you think if it were possible to isolate the traditional crank case from beneath the cylinder , which subsequently became the " crankcase area", with possibly a stepped type piston, with the smaller lower part of that stepped type piston passing through a sealed plate isolating the two areas generating a pressured area in the tradition crankcase area,. could that build up of pressure be used to propel the piston system back up from btdc faster than it would normally take in a traditional 2 stroke set up ...:sherlock:

[Frits Overmars]

What you are describing is a Ryger engine. It has a higher pressure under the piston and it would move the piston faster back up from BDC by a tiny amount if the piston wasn't much heavier than a conventional piston.
And what good would that do? That same higher pressure under the piston will also counteract the combustion pressure that brings the power. No free lunch there.

[wobbly]

At EPO the gas exiting the cylinder is entirely combustion by products and is hot as hell - we see 650* in the header.
At BDC we have an increasingly larger amount of raw fuel/air mixture being overscavenged directly from the case via the transfers.
This overscavenged mixture is cold and if done right it never exits into the header,there simply isnt time for it to be drawn down the pipe diffuser.
We see the result of bad short circuiting ( from port linking for example ) where the egt drops badly and no amount of rejetting will pull this up.
Thus the air/fuel mixture is surrounded by the duct wall, and any temp differential will try to attain equilibrium.
If the wall is hotter than the gas, it will heat the gas, made easyer by the fact that for some period of time the gas must be gradually slowing down,
then sitting still, then slowly accelerating again in the opposite direction ( as a pendulum does at each stroke extreme ).
Whatever the real dynamics of the system,the cooling water must have much less effect on the heat exchange process .
It aint over till the fat lady sings on the dyno,so the test will probably raise even more conjecture no matter what the result.
Unlike our still absent Ryger friend Luc, real dyno graphs will be published on here immediately.

[husaberg]

Unlike our still absent Ryger friend Luc, real dyno graphs will be published on here immediately.

But luc was going to post stuff, but only if you deleted your "Rude" comments
Oh wait you did, and yet he didn't post anything.

Only if Wobbly change his rude words very fast, otherwise no chance !


OK, so I have deleted all the " nasty " posts except for the " good " bit where I suggested that Luc maybe wasnt an incompetent idiot.
This now means I have a life, and I ( we ) would also be really,really friendly if the " hard proof " was posted here - a World Exclusive, as the media would say.
Your turn Luc.



https://www.youtube.com/watch?v=Yd0fBXwDBmo.


i see Ryger are pushing the cleaner two stroke now rather than the most powerful ever..................


The Ryger Revo Clean 1 runs on normal petrol instead of a mixture of petrol with 2-stroke oil. Of course this already causes the first big advantage of having a much cleaner emission compared to the traditional 2-stroke engines.
Due to an ingenious design of the cylinder in combination with the piston and a bottom plate there is no fuel mixture in the crankcase but the fuel will only come underneath the piston where it is compressed and then being released on top of the piston after which ignition takes place.
With the Ryger Revo Clean 1 all the bearings run through the lubricant which is present in the crankcase and the piston is being lubricated via condensed lubrication. Also the gudgeon pin is being lubricated via condensed lubrication. This has resulted in a high degree of durability of the Ryger Revo Clean 1.
All the advantages of the Ryger Revo Clean 1 will help to get the best performance on a kart circuit. Due to the extreme output , the Ryger Revo Clean 1 is the strongest engine available in the 125CC category.
Because the fuel mixture is not pre-heated anymore in the crankcase the overall temperature of the Ryger Revo Clean 1 is much lower which has a very positive effect on the fuel consumption of the engine.

http://rygerengine.com/

[guyhockley]

Sorry TZ350. Bit off topic maybe...
It does concern an engine without poppet valves, though.
Brian Crighton, of rotary engined racers fame, lives near me, but I only found that out a few days ago.

http://www.crightonracing.com/index.htm

Unfortunately, the reason I found out is because his workshop was broken into and everything pertaining to his latest prototype was stolen. Local gossip is of the opinion it was a targeted theft.

https://www.facebook.com/CrightonRacing/

[tjbw]

But luc was going to post stuff, but only if you deleted your "Rude" comments
Oh wait you did, and yet he didn't post anything.


i see Ryger are pushing the cleaner two stroke now rather than the most powerful ever..................

Ryger said "Because the fuel mixture is not pre-heated anymore in the crankcase the overall temperature of the Ryger Revo Clean 1 is much lower which has a very positive effect on the fuel consumption of the engine."

I believe the Ryger fuel mixture receives more compression under the piston, than the VM engine on which it is based, so just before the transfer ports open, the Ryger mixture would heated more than in the VM engine.

The volume compressed under the Ryger piston, is less than on the VM engine, and that could result in reduced fuel consumption, reduced performance and reduced overall temperature.

Now, where did I leave my flameproof overalls ;)

[seattle smitty]

Reading Wobbly's comments above on EGT readings prompts me to ask if anyone knows of a good discussion of how to obtain good reference numbers such as EGT, CHT, A/F ratio, water-temp, etc.. Most of the info I've seen comes from the sellers of these devices, or from four-stroke automotive drag racing sites.

I do get that given all the variables even in just the racing 2-stroke engines (on various fuels) covered here, it might be impossible to offer a one-dimension-fits-all statement on something like sensor placement (such as the "right" distance to place an EGT probe or A/F probe from the piston). I get that one probably shouldn't try to jet or time his engine using a reading from any single guage, that presumably the only way for any of these instruments, separately or together, to tell you anything very useful is once you have recorded their readings while having tuned your specific engine on the dyno and the track. But maybe the savvy guys here can offer some general suggestions on setting up instrumentation so it can eventually mean something . . . or refer me to such a discussion (again, specific to OUR particular engine types).

TeeZee, this thread makes for the best reading on the internet; thanks, bud!!!

[breezy]

What you are describing is a Ryger engine. It has a higher pressure under the piston and it would move the piston faster back up from BDC by a tiny amount if the piston wasn't much heavier than a conventional piston.
And what good would that do? That same higher pressure under the piston will also counteract the combustion pressure that brings the power. No free lunch there.

ok Frits thanks for reply:niceone:. im sure you may have read this at some point which is an extract from a document,

" the pressure ( in the crankcase) may be either controlled manually or automatically. A higher pressure results in higher rotational speed and increased oil thickness or viscosity"

rightly or probably wrongly, i have thought that the "higher rotational speed", refers to the crank rpm. which is what im trying to understand. :scratch:

[wobbly]

The position of an egt probe is relatively simple - 3X bore from the piston face is a good rule of thumb.
The raw numbers are a bit harder to nail down.
On track, the rule is to watch the egt and cht rising in unison,if the egt rises then drops whilst the cht continues to rise you are into deto.
But even easyer is to start rich and drop one jet at a time, and you will quickly discover that the temp will drop a set amount per jet size.
As soon as the egt delta temp drops from say 50*F to 20* with one jet leaner you are seeing the beginning of deto - go back one size.

One small element will change the egt's response in overev, if you have been clever and flat line the advance when approaching the mechanical rpm limit, the egt will
also flatline ( NOT DROP ).
This helps to keep using fuel to make power, not using fuel to control the continually rising egt due to ignition retard putting more and more heat into the pipe.
I use the max egt as seen with max power on the dyno ( at a specific RAD ) to construct a jetting chart,where for every weather data point I hit a specific best power egt number.
This egt ,over a fairly narrow sample range of jetting, will translate into a straight line relating RAD to jet size.

The last real trick to nailing best power jetting is to " read " the bottom face of the ring.
At peak power you will get tiny localized points of detonation of the gas trapped under the ring.
This "power deto " isnt enough to eat a piston crown, but indicates you are right on the limit - just safe enough for a 25 lap final.

[husaberg]

Sorry TZ350. Bit off topic maybe...
It does concern an engine without poppet valves, though.
Brian Crighton, of rotary engined racers fame, lives near me, but I only found that out a few days ago.

http://www.crightonracing.com/index.htm

Unfortunately, the reason I found out is because his workshop was broken into and everything pertaining to his latest prototype was stolen. Local gossip is of the opinion it was a targeted theft.

https://www.facebook.com/CrightonRacing/

I thought he moved to Aussie?
maybe it was to warm and sunny for him?
http://www.jpsnorton.com/race-bikes/roton/

[F5 Dave]

Oh good grief. I'd never think of looking at the bottom of a ring for jetting spec. Guess I'm well too lazy on top of tu stoopid.

[Peter1962]

The position of an egt probe is relatively simple - 3X bore from the piston face is a good rule of thumb.
The raw numbers are a bit harder to nail down.
On track, the rule is to watch the egt and cht rising in unison,if the egt rises then drops whilst the cht continues to rise you are into deto.
But even easyer is to start rich and drop one jet at a time, and you will quickly discover that the temp will drop a set amount per jet size.
As soon as the egt delta temp drops from say 50*F to 20* with one jet leaner you are seeing the beginning of deto - go back one size.

One small element will change the egt's response in overev, if you have been clever and flat line the advance when approaching the mechanical rpm limit, the egt will
also flatline ( NOT DROP ).
This helps to keep using fuel to make power, not using fuel to control the continually rising egt due to ignition retard putting more and more heat into the pipe.
I use the max egt as seen with max power on the dyno ( at a specific RAD ) to construct a jetting chart,where for every weather data point I hit a specific best power egt number.
This egt ,over a fairly narrow sample range of jetting, will translate into a straight line relating RAD to jet size.

The last real trick to nailing best power jetting is to " read " the bottom face of the ring.
At peak power you will get tiny localized points of detonation of the gas trapped under the ring.
This "power deto " isnt enough to eat a piston crown, but indicates you are right on the limit - just safe enough for a 25 lap final.


Wobbly, I seem to recal that for EGT you once gave an optimum value of 660*F ? Is that correct ? And is that a constant value (when using regular pump gas) or is this different for say a 50cc engine or a 250 MX engine ?

[seattle smitty]

Oh good grief. I'd never think of looking at the bottom of a ring for jetting spec. Guess I'm well too lazy on top of tu stoopid.

Same here, Dave!!; I've seen it and guessed it meant that I'd turned the groove in the piston wrong in some dimension (we used to be able to buy semi-finished "blank" pistons).

Wob, you're The Duke!!! I've got to make a print copy of that post and carry it around to memorize! A question: Does the use of straight (with castor or other lube) methanol alter any of that, given that Methanol is a bit more forgiving of being somewhat over-rich (though not at all forgiving of being lean!)??


To anyone, what if any wheeled 2-stroke racing is done with methanol nowdays, other than maybe some open-class dragbikes or streamliners? Long ago, some of the kart racers could run fuel, IIRC.

[guyhockley]

To anyone, what if any wheeled 2-stroke racing is done with methanol nowdays, other than maybe some open-class dragbikes or streamliners? Long ago, some of the kart racers could run fuel, IIRC.

In Britain, on tarmac, hill climbers and pre 1973 racers with the British Historic Racing club can use methanol but you have to stick a big day glow disc on your bike! I think grass track and classic MX may allow it, too, but I haven't been recently perusing their rulebooks...
Speedway?

[wobbly]

The optimum egt number depends on the setup and the fuel.
Working in *F if you must then AvGas ( and similar leaded racegas ) seems to like around 1280 max.
But when using 110 leaded as is allowed in USA kart racing, we see as much as 1360,due to no deto and the high temp makes rpm.
This fuel likes com, and can be run retarded with high com to get big egt numbers that force the pipe to rev on.
But unleaded,be it racegas ( like ELF as was used in 125/250/500 GP ) or high octane pump makes best power closer to 1180.
What is apparent is that the lower octane burns faster in general, thus cannot stand as much timing/com combination.
It likes ignition more than com as a general rule.

[diesel62]

How do you get away with over 700 C and not have a melt down is the piston/bore clearance increased?

Sent from my SM-G900F using Tapatalk

[wobbly]

[QUOTE=diesel62;1131052022]How do you get away with over 700 C and not have a melt down is the piston/bore clearance increased?

The CR125 engines as used in SKUSA are stock com and are run retarded on VP C12.
This is way too good fuel needed for the tune,and the retarded timing allows the high octane to run real hot to get extra overev.
The drivers gearchange at 12400,and they will run to 12600 in top gear.
On the 98 unleaded used previously any more than 1260* was a meltdown and they only just went to 12,000 - so many pistons were being destroyed the Yanks idea of a fix was to run
way way better fuel, so you can be real dumb on the jetting at still get away with it.
Now the bottom ends blow up due to the revs unless regularly maintained.

[chrisc]

Well, the SX50 ex duct might be on the large size at 27x29mm but at least it's not SX65 big! Exhaust mani is from the SX65 on SX50 cylinder.

https://c1.staticflickr.com/5/4290/35330681072_80b8678783_c.jpg (https://flic.kr/p/VQ3YzE)
Untitled (https://flic.kr/p/VQ3YzE) by Chris Cain (https://www.flickr.com/photos/sonscc/), on Flickr

Extending the aux port duct to the end of the duct and into the new spigot to form ears will be on the cards as has been advised on this thread. I'm wondering though, will the downsides from increasing duct volume in an already too large duct overcome the positive effects of increase the aux ducts to the spigot?

Another for ref:
https://c1.staticflickr.com/5/4287/34656659484_f099d9de19_c.jpg (https://flic.kr/p/UNurrN)
Untitled (https://flic.kr/p/UNurrN) by Chris Cain (https://www.flickr.com/photos/sonscc/), on Flickr

[breezy]

ok Frits thanks for reply:niceone:. im sure you may have read this at some point which is an extract from a document,

" the pressure ( in the crankcase) may be either controlled manually or automatically. A higher pressure results in higher rotational speed and increased oil thickness or viscosity"

rightly or probably wrongly, i have thought that the "higher rotational speed", refers to the crank rpm. which is what im trying to understand. :scratch:

so its high a pressure oil lubricating system to reduce friction and improve piston ring sealing.....increasing ability to rev.... maybe

[Frits Overmars]

Well, the SX50 ex duct might be on the large size at 27x29mm but at least it's not SX65 big! Exhaust mani is from the SX65 on SX50 cylinder.The standard KTM 50SX exhaust duct diameter is way too big, and so is the 65SX header diameter. Below left a standard 50SX duct, right and a sleeved-down duct.
This is still a dry sleeve; a much cooler-running wet sleeve with extended aux ducts is on the drawing board.
331452

[Frits Overmars]

im sure you may have read this at some point which is an extract from a document,
" the pressure ( in the crankcase) may be either controlled manually or automatically. A higher pressure results in higher rotational speed and increased oil thickness or viscosity"I'd sure like to know what you're talking about, Breezy. Which document? Which engine? And which pressure? Scavenging pressure? Lubrication pressure?

[jasonu]

The standard KTM 50SX exhaust duct diameter is way too big, and so is the 65SX header diameter. Below left a standard 50SX duct, right and a sleeved-down duct.
This is still a dry sleeve; a much cooler-running wet sleeve with extended aux ducts is on the drawing board.
331452

How does a company like KTM with presumably huge resources and cash get something like this wrong?

[G Jones]

Re the GRM crank with add on web plates.
This is exactly what some new R&D idiots did to the Aprilia after Jan retired - sadly for them it suddenly lost a heap of power.
In a reed engine there is a bottom limit to the case volume that sits at around 1.3 in my experience.
The RV engine loves additional volume than that,so removing the plates on the GRM reed,and using Mallory may not work if the case becomes too big.Just what is TOO big though ? :rolleyes:

[dutchpower]

How does a company like KTM with presumably huge resources and cash get something like this wrong?

If you have 99,9 % of the market why bother

Exh . duct is already to big to start with

[jfn2]

dutchpower:
I'm sorry but I don't quite understand your attached pic. Are the red lines measurements?

[dutchpower]

Tool to measure

[wobbly]

Re the GRM case volume - as I have said a dozen times I have never been able to get better power going under 1.3 case ratio with a reed engine.
Any bigger and you have to run the reeds so soft,they loose control at higher rpm and power drops - the exact opposite of what a big case should be capable of.
In a KZ10B TM kart engine I cut 5mm of the reed face on the case.
This needed stiffer reed backups to get the power back, but that lost too much mid power capability.
Adding a 10mm spacer ( making the reed 5mm further out than stock ) needed the reeds so soft that the small amount of mid gained
from them was completely lost by a huge drop in overev power.

Re the KTM exhaust duct - yes they are stupid huge and adding ears to try and promote the Aux blowdown flow is very overwhelmed by the fact that
you have just made a huge power loosing duct, an even bigger liability.

[dark art]

How does a company like KTM with presumably huge resources and cash get something like this wrong?

To be fair, they may not get it so wrong, it's a auto-clutched direct driven motocross bike for 8/9 years old kids. Most minis seem to have a huge exhaust duct, including 85's

[husaberg]

How does a company like KTM with presumably huge resources and cash get something like this wrong?


To be fair, they may not get it so wrong, it's a auto-clutched direct driven motocross bike for 8/9 years old kids. Most minis seem to have a huge exhaust duct, including 85's

KTM have no real competition in the mini MX market
The older Beta powered KTM50's 02- 08 were actually faster in a straight line drag, but slower where it really counts arround an tight MX track.
The 09 onwards ones with KTM's own engine however had a clutch that was much lower maintainace, which is a boon for MX dads.
AS no engine mods are allowed in most kids MX, its irelevent if moding the engines vex duct makes it faster.

[peewee]

How does a company like KTM with presumably huge resources and cash get something like this wrong?

and if they been lurking around here like some have suspected, then theres no excuse for getting anything wrong. heres what I think. theyre 250 engine has been around 45-47hp for a lot of years and really you don't want more than that for motox so why spend a bunch of time with the ports, if anything I think they been trying to smooth it out, mostly with crappy head designs like what they did in '14 when the put a huge radius on the transition from band to bowl. I think that head went in the scrap pile the following year because they have a new design now. its seems theyre more focused on mainly suspension/chassis and rightfully so. they have been doing some work on making the cooling system even more efficient which is never a bad thing but the ports in the very newest cylinder doesn't look much different than years ago

[190mech]

Looks like KTM knew a decent head design back in the 80's;
http://www.ebay.com/itm/KTM-250-Cylinder-Head-T50-/122447212996?hash=item1c826c31c4:g:tisAAOSwls5Y8RZ 7&vxp=mtr

http://www.ebay.com/itm/KTM-250-KTM250-MXC-CYLINDER-HEAD-OEM-AHRMA-NICE-1986-/272731172249?hash=item3f800b6d99:g:1DUAAOSwCU1Yzux q&vxp=mtr

Maybe the marketing department had a different idea later on..

[peewee]

I will be logging egt and deto level in acceleration testing at the same rate as the engine is run on track.
Its my opinion as well that a shorter duct ( thus longer header ) would indeed make the header temp react faster.
But is that what is needed.
As you exit the corner at well less than peak power rpm, a cooler pipe will for sure give a wider dynamic power range, and its thus my belief the duct should be longer
due to this effect.
I have already track tested this by in effect cooling the back of the spigot by allowing water right around the duct and up to the flange back face.
I also concurrently cut Aux ears right thru the spigot, so the drop in track time by 3/10s cannot be attributed to one or other of the changes directly.
The Aux ears did not affect low end power on the dyno at all, but on track the driver, and the datalogger said it hooked up and drove out noticeably quicker - as well
as the big increase in overev power the dyno showed conclusively.
The pic shows the ears, and the slots.The red line is the new duct exit being cast at the factory now for testing as well.

with the ktm 2wheeler mostly finished I reckon ill start back on the twin that's been sitting in the corner for ages. added my own exh cooling and a wee bit more material for large aux passages :msn-wink:. its got a 4spd clutchless gearbox with manual 6th and 1st gear removed. crankshaft is skf roller bearings all the way across with ktm rods. should be a fun time :eek:

[chrisc]

Re the KTM exhaust duct - yes they are stupid huge and adding ears to try and promote the Aux blowdown flow is very overwhelmed by the fact that you have just made a huge power loosing duct, an even bigger liability.

Thanks for confirming my hesitations Wob. No doubt another reminder to me that improvements in isolation of other required factors often aren't improvements in a 2 stroke engine at all :scratch:


The standard KTM 50SX exhaust duct diameter is way too big, and so is the 65SX header diameter. Below left a standard 50SX duct, right and a sleeved-down duct.
This is still a dry sleeve; a much cooler-running wet sleeve with extended aux ducts is on the drawing board.
331452

As always Frits, you show your skills at being both very informative and very alluring. Thanks! I have to ask now, is that your SX50 cylinder? Please excuse my ignorance but was the duct machined out and a sleeve press fit into it? At least that's what my initial thoughts are on what a "dry sleeve" would be.

I see the file name is from September 2013. Am I able to see more of the work done to it? If so, where? There's some limited discussion on pitlane on the SX50 but I haven't seen that cylinder before.

[Juho_]

That then is the problem with the AM6.
If you have holes in the skirt above the small end that connect the Aux and the A transfer,then it will run rich,and will not respond at all
to jet changes.
The seemingly rich mixture in the Exhaust is caused by the short circuiting, not by rich jetting, so you go leaner and nothing happens.

A file I have of a fully tuned TZR50 that puts out 18Hp Crank at 13,000 with triple Exhaust ports and this has a spigot exit area equivalent to 22mm.
This is 78% of the Exhaust effective area, and gives a Mach of 0.8 , absolutely fine.
Going slightly bigger in displacement or making more power than this would put the exit velocity close to sonic, so yes this may well be an issue as well.

The case com ratio is a very important element, guessing or not measuring it correctly isnt an option.
PS - you have a worn out piston available, drill a hole in it.
Sorry for a late reply. I wanted to reply with correct measurements and atleast some results..

Crankcase volume, measured as accurate as possible (drilled a piston I could no longer use and filled the reedvalve with vinamold so it would be fully sealed) .
It is 300cc @ TDC with the "new" cylinder (has slightly smaller transfer ducts than the previous one), so the crankcase compression ratio is 1.224.
Too low, as you have said.

There are a few ways I could reduce it.. but not much.. larger reedvalve could take away some volume but I don't like it (the current already has enough reed area..it is the same as KTM 65SX VForce 3), and filling the crankcase below cylinder skirt or shorter connecting rod (94mm to 90mm) so I would get rid of the 5mm aluminium spacer.
The crankcases haven't been grinded that much, only transfer entries have been matched to the cylinder.

The previous cylinder had a very bad quality nicasil coating. It started flaking after the first failed combustion chamber o-ring seal, and got in extremely bad condition while using it (couldn't find an used aluminium D50B0 OEM cylinder..this one was a copy cylinder, made in Taiwan).
That caused loss of power too, of course. But so did the 2-ring piston with large 'holes' above piston pin (short circuiting.. you (wobbly) were 100% right about this to cause the problem).

After I found an used D50B0 OEM aluminium cylinder (though it had quite bad scratches...of course the seller did not get me any good quality pictures, so I could have not seen them before buying), and did some minor porting (approx. 190 degress timing + large radius for the exhaust port and also radius for the transfer ducts..and got started porting 1 aux exhaust port and 1 main transfer port...until my 90 degree mini grinder broke, so I left it as it was).
Then I did some testing. Didn't take long till the flywheel side crank bearing failed (probably was a 'pirate' bearing..because it failed so quickly), so I replaced both bearings (FAG 6204/C3 and 6303/C3 + new NBR70 oil seals (yes, I know, they are bad..and also made in Taiwan or China. No Viton seals were available off the shelf).

Now I've reached 13,3hp@11,500rpm and max. 14,160rpm (on 4th gear, 6th gear it'll rev up to ~13,900rpm).
This is a GSF Dyno result, and can be repeated. Previously the best result has been 13,5hp@11,500rpm.
It has reached almost 14hp@11,300-11,500rpm too, but it cannot be confirmed 100%.

I know the results cannot be compared to a real dyno.. but on dyno day it did 9hp on GSF Dyno, and 12,5hp on Fuchs dyno (ran way too rich).
This was almost 2 months ago, outside temperature had been less than 10 celsius degress, and I had no time to adjust it on dyno.

It is interesting to see, how much the piston itself made a difference and only small modifications.
When I get a new 90 degree mini grinder, I can start porting the cylinder a bit more.. it is clear it's lacking mostly blowdown area.

----

Something interesting I found during fixing a GasGas 125cc engine..
It had problems with E98 fuel (gas), and produced very low power. On E85 it was a different engine (originally was meant for E85 fuel, so combustion chamber had less volume).

It did 31,3hp@12,437rpm on dyno (running way too lean, because carb bowl got empty when 'riding' it on 5th or 6th gear at high revs).
And max rpm was ~13,300. (quite a lot for an enduro engine)

So, after fighting with multiple problems, I found out the carb (PWK38 air striker) had a bad seal on jet block and the engine sucked extra fuel from there (explained why it wanted a lot smaller jets).
I couldn't get a new seal, because it was weekend, so I took my Keihin PWM 40.5mm carb and threw it in (some random jets, that I thought would work fine there) and emptied the fuel tank and filled with E98 fuel + Castrol Power1 (4%).

After I got it running and idling, I went testing.
Suddenly the engine had woken and had more power than ever on E98 fuel. About as much as with E85 fuel!
(I had jetted it on previous carb to work fine on higher rpm's and got some power back)

Best power I got on E85 + PWK 38mm was ~28hp@12,300rpm. On PWM 40.5mm + E98 max. ~28hp@11,400rpm.
Previously on E98 + PWK 38mm only 20hp@10,140rpm (after jetting it) - simply had no power. These are GSF Dyno numbers.

I could not belive the carb made such a huge difference.
And I'm not sure if the seal could have affected so much.. because the fuel mixture was not too rich at high rpm's after jetting.
Is it possible that a 125cc 2-stroke engine would actually prefer that large carburetor ??

[Frits Overmars]

As always Frits, you show your skills at being both very informative and very alluring. Thanks! I have to ask now, is that your SX50 cylinder? Please excuse my ignorance but was the duct machined out and a sleeve press fit into it? At least that's what my initial thoughts are on what a "dry sleeve" would be. I see the file name is from September 2013. Am I able to see more of the work done to it? If so, where? There's some limited discussion on pitlane on the SX50 but I haven't seen that cylinder before.Thanks or the flowers Chris. You are right, the duct was machined and the sleeve was pressed in. The cylinder isn't mine, it belongs to my friend Jan Schäffer (the German giant who wins 50 cc races). He is quite open about his engines and chassis, but he publishes most of his work on a closed forum, so I do not feel at liberty to show much of it here. But you may find some info on his company website https://langtuning.de/Shop2/Startseite-1 and on http://www.simson-rennteam.de

[wobbly]

Been there done that with Airstrikers.
The stock 38 PWM will flow more air and make way better power than the same 38 PWK with Airstrikers.
The Airstriker design is specifically designed for better response off low speed corners, but the mess it makes of the airflow down the venturi
and into the carb body looses a heap of power at higher airflow numbers in the mid range to peak and beyond.
Wouldnt use an Airstriker if you gave it to me.

[lodgernz]

Did you check for dribble at steep angles ? I mocked up my pair the other day and found that even with the tracts dead vertical there seemed to be no weeping from the pilots...I'll be using mine with the top covers pretty well horizontal - so back a bit from full vertical downdraft.

Yes, I found the same, none of my carbs dribble on my angle jig, even at steep angles. However, I suspect they would in real life when braking for a corner.
The TA carb is already at 45º downdraught with the float bowl perfectly level, so it's unlikely to dribble.

[diesel pig]

Been there done that with Airstrikers.
The stock 38 PWM will flow more air and make way better power than the same 38 PWK with Airstrikers.
The Airstriker design is specifically designed for better response off low speed corners, but the mess it makes of the airflow down the venturi
and into the carb body looses a heap of power at higher airflow numbers in the mid range to peak and beyond.
Wouldnt use an Airstriker if you gave it to me.

That's worrying Wobbly I use a 36 PWK on my 100cc bucket for the TPS and solenoid powerjet, Would the PWK Airstrikers be messing up the carburation on it?
I take it the Airstrikers are these fences on the bottom of the bellmouth?

[F5 Dave]

Yeah I have 35 airstrikers on my 496 CPI . so? Snap end off with some pliers?

Mind you its a roadbike which is why only 35s.

[wobbly]

Yeah I have 35 airstrikers on my 496 CPI . so? Snap end off with some pliers?

Mind you its a roadbike which is why only 35s.

Its easy enough to grind off the ramps, but the PWM has a different intake bell shape as well and that is also able to be replicated
so you get the performance as well as the PJ and TPS.

[husaberg]

Its easy enough to grind off the ramps, but the PWM has a different intake bell shape as well and that is also able to be replicated
so you get the performance as well as the PJ and TPS.

out of interst what carb did nigel run an RGV TM mikuni or a Keihin shorty TPS Solinoid PJ.
That's the other advantage of the TPS ELectirc PJ MX Kehin (ie 98ish KX125)they were about 25-30mm shorter than the av Keihin.

[emess]

I won some power by making the auxiliary ports bigger, but they were already too high I thought.
So I made sure the APC cylinders had lower auxiliary ports

Jan, why did you think the auxiliary ports were too high?

If you could not have a power valve would you make the aux ports open at the same time as the main exhaust?

Mick

[jamathi]

Jan, why did you think the auxiliary ports were too high?

If you could not have a power valve would you make the aux ports open at the same time as the main exhaust?

Mick

I already knew that too high auxiliary ports cost power.
So I would never make them as high as the main port!
Unless you make the main port lower, which I did for some time in previous engines (Jamathi, Bultaco).
But different heights are surely better!
And I don't consider a power valve that important....

[emess]

The standard KTM 50SX exhaust duct diameter is way too big
Frits, I'm curious, how do you work out the optimum duct diameter for an engine.

Mick

[emess]

I already knew that too high auxiliary ports cost power.
So I would never make them as high as the main port!
Unless you make the main port lower, which I did for some time in previous engines (Jamathi, Bultaco).
But different heights are surely better!
And I don't consider a power valve that important....

Thanks Jan

without a power valve what would you work on to improve the lower end of the powerband

Mick

[jamathi]

Thanks Jan

without a power valve what would you work on to improve the lower end of the powerband

Mick

The lower end of the power band is not the most important.
It is important that the engine revs freely, does not stop suddenly at high revs.
For acceleration the power after the gear change is most important.
This is what the riders feel most.
A lot of power at low revs can make that you can not open the throttle....
And usually does not improve lap times.

[shnaggs]

Frits, I'm curious, how do you work out the optimum duct diameter for an engine.

Mick

^^^^^ This

I tried making a half ass insert for a ktm 125. It was just a ring that was sandwiched by the pipe and it had a tongue that went up floor. Lost 5hp :eek5: I can only guess that it closed off the duct too much, and/or it exaggerated the mid point area to outlet area ratio....which ever that should be???

[Frits Overmars]

Frits, I'm curious, how do you work out the optimum duct diameter for an engine.Have you got a spare minute Mick? :D
In essence it's about Helmholtz resonance. You can find the basics via Wikipedia but don't get your hopes up; establishing the optimum diameters of a pipe is far more complicated than finding the correct lengths. That is why I developed a simple pipe concept that should get you in the ballpark without too much physics and math.
331480 331479

[emess]

I developed a simple pipe concept that should get you in the ball park without too much physics and math.

Thanks Frits, I had seen your pipe concept diagram and succesfully put it into practice with some help from Engmod but can't see how it works with Wobbly's 75% area rule. Are the two ideas compatible?

I love to understand the derivation of formulae and understand that is asking way too much but is it possible to say what Dx in the older version or X in the later version represents?

Mick

[Frits Overmars]

Thanks Frits, I had seen your pipe concept diagram and succesfully put it into practice with some help from Engmod but can't see how it works with Wobbly's 75% area rule. Are the two ideas compatible?More or less. Wobbly starts with the total exhaust window area; I start with the exhaust blowdown area.


I love to understand the derivation of formulae and understand that is asking way too much but is it possible to say what Dx in the older version or X in the later version represents?X is an empirical value to which the diameters are related. X represents the cumulative effect of quite a number of variables that do play a role in a running engine,
but whose values may be unknown to the beginning two-stroke tuner. I tried to concoct a simple exhaust concept, you know.

[emess]

Many thanks Frits, Jan and Wobbly for your answers and massive contributions to this site and for raising my understanding of 2-strokes and to TeeZee for this great site.

Mick

[diesel62]

Many thanks Frits, Jan and Wobbly for your answers and massive contributions to this site and for raising my understanding of 2-strokes and to TeeZee for this great site.

Mick
Second that ☺️

Sent from my SM-G900F using Tapatalk

[wobbly]

Frits is dead right,the duct exit should ideally be tied to the blowdown area, but I have carried on using the total effective Ex area ( that is the
chordal area X the down angle cosine ) as when you use the 75% reduction at the exit,EngMod invariably throws up a corresponding velocity
of 0.8 Mach at the spigot mount face..This has proven to be the magic number to shoot for in a huge range of builds.

And Jan is dead right as usual about the relative heights of the main and Aux ports.
A split of 2* to 4* opening angle is needed or you loose power.
This I believe is due to smearing of the exit wave amplitude - the main port opening first allows the biggest pressure delta to create a strong initial wave front
exiting into the duct.
Once this has occurred, the lower Aux ports simply bleed down the remaining blowdown pressure.
If the Aux are the same height,the much longer path length down the Aux duct causes the initial exiting flow to be smeared out in time, as well as a much lower
peak amplitude - result,less power.

[dutchpower]

So lots of blowdown area Frits

[Frits Overmars]

So lots of blowdown area FritsJan Thiel once suggested that you cannot have too much blowdown time.area. But you can have too much exhaust timing, you can have too much vicinity between the exhaust port and the A-transfers, you can have shortcircuiting between the auxiliary exhaust ports and the transfers via the gudgeon pin bores in the piston, and finally you can have port shapes that are too harsh on the piston ring.

[dutchpower]

Thanks Frits :yes:

[jonny quest]

"You may not have enough space between exhaust port and A port"

Is this maybe what you meant, Frits?

[jonny quest]

Jan Thiel once suggested that you cannot have too much blowdown time.area. But you can have too much exhaust timing,

you can have too much vicinity between the exhaust port and the A-transfers,

you can have shortcircuiting between the auxiliary exhaust ports and the transfers via the gudgeon pin bores in the piston, and finally you can have port shapes that are too harsh on the piston ring.

You wrote this Frits. In my above post I was wondering if what I wrote, is what you meant to say.

[SwePatrick]

About durations on aux exhaustports vs main exhaustport.

The powerloss due to too high duration on auxports, wouldn´t it also depend on the shape of the auxports runners?

If they are taking a big curve before entering the exhaustduct it would be more important to let them have less duration then the main?
Thereby it would be less important if they are having a almost 'straight shot' from face of the port down against the exhaustduct?

I´m thinking of what Wobbly wrote about the aux is 'bleeding' the 'rest' of the exhaustpressure.

Rgds
Patrick

[peewee]

I don't recall anybody asking about this. since most cylinders have a exh passage far to short I guess its still recommended to put the exit at 75% ? some cylinders cant get even close to a proper passage length because of packaging limitations. mine was only 50mm on a 500cc but there was really not much I could do since the front tire would of smashed it every time the suspension compressed

[Nath88]

Does anyone have experience with spark plug ion sensing with 2 stroke engines (or other types)?

331512

Essentially pinches a little bit of the spark current to charge the capacitor, which then applies the charge to the spark gap after the spark current has finished.
The amount of current that flows is proportional to the concentration of ionised gas at the plug gap which indicates pressure. No combustion = no current flow so misfire is easily detected. Post processing can detect knock (rapid pressure rise) and optimise spark timing (peak pressure timing).

All I'm looking for is accurate misfire detection... How hard could it be.

[Frits Overmars]

Pretty hard - in a two-stroke. Saab did quite some spark plug ionisation monitoring research with good results, but that was in a four-stroke.
In a two-stroke the squish action is much more violent and the concentration of ionized gas at the plug gap depends more on squish velocity than on pressure.
Here is some reading on the subject.
331522

[2T Institute]

Does anyone have experience with spark plug ion sensing with 2 stroke engines (or other types)?

331512

Essentially pinches a little bit of the spark current to charge the capacitor, which then applies the charge to the spark gap after the spark current has finished.
The amount of current that flows is proportional to the concentration of ionised gas at the plug gap which indicates pressure. No combustion = no current flow so misfire is easily detected. Post processing can detect knock (rapid pressure rise) and optimise spark timing (peak pressure timing).

All I'm looking for is accurate misfire detection... How hard could it be.

Is that from that famous bit of plastic snake oil the Icat/Direct Hits or whatever they call it now?

[seattle smitty]

FWIW (repeat, repeat), an electronics engineer, inventor, and sometime amateur drag-racer, Christopher Jacobs, PhD, developed an aftermarket ignition for the automotive world, mostly, about 25 years ago, that purported to do what you describe. The ignition was well-liked by some, the company (Jacobs Electronics) seemed to have some problems, and I gather that Jacobs became tired of business hassles and sold the company so he could get back to inventing, in the medical field. He wrote a book on the basics of ignition systems: The Doctor's Step By Step Guide to Optimizing Your Ignition.

[teriks]

Does anyone have experience with spark plug ion sensing with 2 stroke engines (or other types)?

331512

Essentially pinches a little bit of the spark current to charge the capacitor, which then applies the charge to the spark gap after the spark current has finished.
The amount of current that flows is proportional to the concentration of ionised gas at the plug gap which indicates pressure. No combustion = no current flow so misfire is easily detected. Post processing can detect knock (rapid pressure rise) and optimise spark timing (peak pressure timing).

All I'm looking for is accurate misfire detection... How hard could it be.
Only as a user, SAAB used ion sensing in their car engines since 1994.
Never had to mess with it though, haven't had a problem.. so far.

Saab Trionic’s ignition system ...
The spark plugs are used as sensors to detect combustion and preignition/pinging.
This renders camshaft position detector and knock sensor redundant.

[crbbt]

Harley also ion sensing for knock detection. apparently the motor is too mechanically noisy to use a regular knock sensor.

I believe one of the issues with ion sensing and data logging accurately was the lack of time greater than 6000rpm. I was interested in peak cylinder pressure which can be worked out using ion sensing

[Jannem]

Harley also ion sensing for knock detection. apparently the motor is too mechanically noisy to use a regular knock sensor.

I believe one of the issues with ion sensing and data logging accurately was the lack of time greater than 6000rpm. I was interested in peak cylinder pressure which can be worked out using ion sensing

The owner of TFX is also into 2 strokes and their stuff could be used in addition of cylinder pressure to measure real life pipe and case resonances. http://www.tfxengine.com/

[Norman]

I saw some info about the Mozzi piston. It had a titan center insert in the top of the piston. If to believe the dyno chart it gave some extra power. BUt, what if you put a well chosen ceramic layer at the top of the piston, leaving the squish area without ceramic, would this give the same effect? Titan has a themal conductivity of about 20 W/(m*K) and some ceramics I have seen has 0,5-2 W/(m*K). If the titan insert has a thickness of 5 mm and we substitute this with a 0,5 mm ceramic? What do you think about this Wobbly? The higher curve is for a Mozzi piston, the lower is original.

[wobbly]

The latest 3D printers can do two materials concurrently https://www.desktopmetal.com/ so that may be an option if they can do the correct high silicon alloy.
But I use HPC ceramic coating of the combustion chamber bowl only, and the non squish area of the piston in many engines.
The best example was a SeaDoo World Champ Ski, this was a " stock " 950 " and made just over 8 Hp more doing that treatment.
It very quickly ended up with burnt on oil so looked completely normal.

[chrisc]

On a 50 (39.5mm bore), is there any advantage to running a 10mm plug such as a NGK R0373A-10 over the 14mm R7376-10?
Potentially less surface area on the small combustion chamber to extract heat? Maybe less room in the chamber to create the right shape?

Would a 19mm reach plug would be better than a 12.7mm reach plug on the basis that there's more plug in the head insert and more vertical surface area to pull heat out of the plug, into the insert then into the coolant?

Is the 10 heat range plug a reasonable heat range to start with for this 50 I'm building?

[Norman]

The latest 3D printers can do two materials concurrently https://www.desktopmetal.com/ so that may be an option if they can do the correct high silicon alloy.
But I use HPC ceramic coating of the combustion chamber bowl only, and the non squish area of the piston in many engines.
The best example was a SeaDoo World Champ Ski, this was a " stock " 950 " and made just over 8 Hp more doing that treatment.
It very quickly ended up with burnt on oil so looked completely normal.

Thank you for your reply Wobbly. With the risk of knocking on open doors here, I am thinking that the squish is getting even better cooled, as well as the plug, using the method you describe. Very interesting.

[Nath88]

Pretty hard - in a two-stroke. Saab did quite some spark plug ionisation monitoring research with good results, but that was in a four-stroke.
In a two-stroke the squish action is much more violent and the concentration of ionized gas at the plug gap depends more on squish velocity than on pressure.
Here is some reading on the subject.
331522

Good light reading material there thanks Frits, looks like trying to correlate the ion current to the cylinder pressure for the two-stroke would be flawed, hopefully the presence of flame can still be detected.

It isn't difficult to do electrically, I've run a model of the circuit to ensure I don't fry the CDI, will need to isolate the coil from the frame, then add the sensing circuit in between.

[wobbly]

Yes I would think that the small diameter plug body, in the longer 19mm size would for sure pull less heat out of the chamber
and be easier to cool.
But you would need to do the calculation of exposed body area in the chamber divided by the threaded contact area in the insert to see if any inherent advantage is present.
But the nose configuration is the same trick fine wire electrodes, so no combustion performance issues to be concerned with.

[Jannem]

We want to keep the squish area boundary layer and thus the trapped end gases cool - you work it out, I have but aint telling.


I appreciate the hard earned experience you are sharing and don't expect getting all the answers laid out.

I'll resort to a shadetree solution of putting unpleasant looking burr finish to the squish surface. Adds surface area for cooling and helps wet flow.
Whether it would be a good idea to do that to the piston outer perimeter, I can't weigh the pros and cons. Similar rough finish could help the squish wet flow, but would add surface area to the piston to absorb more heat to the sides. On the other hand, polished surface might leave it somewhat wet and charge could be burning on the surface longer. Or evaporate, compress and detonate. I'll try a matte scotchsbrite surface there as a compromise with polish in the center.

Coatings are out for us anyway, but this is just an elbow grease kinda thing.

[Jannem]

We had to go with a compromised piston, which has higher than desirable dome. Piston top thickness is however 3.5mm. Thinking about machining a flat on top to lower the dome for improved flow and reduced combistion surface area. 44mm piston.

What would be a safe amount to take off? Are there reasons why this would be simply a bad idea?

If I can make it flat all the way to the squish pad, would you round off the corner at the piston top or leave it sharp?

[Frits Overmars]

Piston top thickness is 3.5mm. Thinking about machining a flat on top. 44mm piston.
Are there reasons why this would be simply a bad idea?Yep, 3,5 mm is already too thin for a 44 mm diameter piston.

[Jannem]

Yep, 3,5 mm is already too thin for a 44 mm diameter piston.

That's it then. :) Thanks!

[chrisc]

A shout out of thanks to Guy Hockley from the UK for helping me get my hands on some Vinamold to get a proper look at these SX50 ports. What a good dude. I've found it hard to get information on the SX50 online so I thought I'd post some up for those interested.

https://farm5.staticflickr.com/4105/35521432312_21684a266e_z.jpg (https://flic.kr/p/W7UCh9)
I just used a small pot and my camping cooker to melt it down. I held it about 250mm above the flame because even at the lowest heat, the vinamold melted quickly. I didn't want to burn it.
I stuffed up my first attempt by not putting a screw into the vinamold so I could get it out easily. I also left it overnight before trying to get it out. Took a while to evacuate the failed attempt :weird: I found it easiest to get out when still a little warm, maybe 15 minutes after pouring (it was 4 degrees in the shed too).

https://farm5.staticflickr.com/4210/35521537702_0f0903b640_z.jpg (https://flic.kr/p/W7VaBd)

https://farm5.staticflickr.com/4034/35521433122_603a4e3ec0_z.jpg (https://flic.kr/p/W7UCw7)

I started to get the hang of it though not as good as this other white version I found on the internet:
https://farm5.staticflickr.com/4260/35521430752_79220fce82_o.jpg (https://flic.kr/p/W7UBPf)

My first (very unprofessional) impressions are that the B transfer ducts could move further around to the C port to square up the inner wall. The C transfer duct is super duper skinny in the bend. The B port roof angle is quite flat. The B transfer inner duct radius is very square and unlike the teacup shape which has been recommended. The A transfer duct inner radius is comparatively much better although has a flat in the middle of the 2 radius. The aux ex port entry is quite flat unlike the big hook of the RSA125. There are weird bumps in the A port wall which can't be good for flow direction.

Also found this port rubbing online here: link (http://www.50c.nl/Archief%20Ton%20Kooyman-Album-1/Diverse%20race/KTM%20SX50/index.html). I took some cord width measurements of the ports
Ex port: 28mm, Ex aux ports: 10mm, A port 16mm, B port 16mm, C port 12mm. I measured the transfer port height at 9mm also, not the 10.5mm of the rubbing. The 10.5 doesn't make sense to me. If you add the height of the aux port and port top to deck height (9+22=31mm) is the same as the transfer port top (31mm) meaning practically no clearance between ex aux port and A port according to the rubbing.
https://farm5.staticflickr.com/4020/35690268175_486593d327_o.jpg (https://flic.kr/p/WnPXii)

[peewee]

you can put a light coat of oil on the passage walls for easier removal of the vina

[dark art]

[QUOTE=chrisc;1131053519


Ex port: 28mm, Ex aux ports: 10mm, A port 16mm, B port 16mm, C port 12mm. I measured the transfer port height at 9mm also, not the 10.5mm of the rubbing. The 10.5 doesn't make sense to me. If you add the height of the aux port and port top to deck height (9+22=31mm) is the same as the transfer port top (31mm) meaning practically no clearance between ex aux port and A port according to the rubbing.
https://farm5.staticflickr.com/4020/35690268175_486593d327_o.jpg (https://flic.kr/p/WnPXii)
The cylinder "port-map" in the pic can be from a older version of the ktm50 or is probably modified, I can´t remember all the dimentions of the stock cylinder but the main exhaust port width is around 28mm, definitely not 32mm.

The 31mm may not refer to "deck height" but to top dead center (TDC), wich may not be the same.

[adegnes]

A shout out of thanks to Guy Hockley from the UK for helping me get my hands on some Vinamold to get a proper look at these SX50 ports. What a good dude. I've found it hard to get information on the SX50 online so I thought I'd post some up for those interested.

https://farm5.staticflickr.com/4105/35521432312_21684a266e_z.jpg (https://flic.kr/p/W7UCh9)
I just used a small pot and my camping cooker to melt it down. I held it about 250mm above the flame because even at the lowest heat, the vinamold melted quickly. I didn't want to burn it.
I stuffed up my first attempt by not putting a screw into the vinamold so I could get it out easily. I also left it overnight before trying to get it out. Took a while to evacuate the failed attempt :weird: I found it easiest to get out when still a little warm, maybe 15 minutes after pouring (it was 4 degrees in the shed too).

https://farm5.staticflickr.com/4210/35521537702_0f0903b640_z.jpg (https://flic.kr/p/W7VaBd)

https://farm5.staticflickr.com/4034/35521433122_603a4e3ec0_z.jpg (https://flic.kr/p/W7UCw7)

I started to get the hang of it though not as good as this other white version I found on the internet:
https://farm5.staticflickr.com/4260/35521430752_79220fce82_o.jpg (https://flic.kr/p/W7UBPf)

My first (very unprofessional) impressions are that the B transfer ducts could move further around to the C port to square up the inner wall. The C transfer duct is super duper skinny in the bend. The B port roof angle is quite flat. The B transfer inner duct radius is very square and unlike the teacup shape which has been recommended. The A transfer duct inner radius is comparatively much better although has a flat in the middle of the 2 radius. The aux ex port entry is quite flat unlike the big hook of the RSA125. There are weird bumps in the A port wall which can't be good for flow direction.

Also found this port rubbing online here: link (http://www.50c.nl/Archief%20Ton%20Kooyman-Album-1/Diverse%20race/KTM%20SX50/index.html). I took some cord width measurements of the ports
Ex port: 28mm, Ex aux ports: 10mm, A port 16mm, B port 16mm, C port 12mm. I measured the transfer port height at 9mm also, not the 10.5mm of the rubbing. The 10.5 doesn't make sense to me. If you add the height of the aux port and port top to deck height (9+22=31mm) is the same as the transfer port top (31mm) meaning practically no clearance between ex aux port and A port according to the rubbing.
https://farm5.staticflickr.com/4020/35690268175_486593d327_o.jpg (https://flic.kr/p/WnPXii)

Great stuff! Much appreciated!

[F5 Dave]

I put the tape on the port faces of a clean bore then a light spray of silicon spray. Overpour a little so you have something to hold onto and ties them together at the right spacing. Easy peasy to wiggle out.

[katinas]

Hi,

Sorry for so long time without info, but just want to test as more as I can before say something.

Now just current results without details :

Done about 500 km.

Testing three different types of cylinders ( two from Honda NS, and last from Honda Cr 125 86") and three different types of pistons.

Very interesting, so different type, but result was the same. The power feels like 20-25 Hp, no more. Power band 8600-11500 rpm. ( harmonizes with pipe dimensions). It revs, but feels that engine want to overcome something.

First piston heavily seized in second gear at 100 km/h, but luckily left hand remember old habit ( absolutely my fault, cold engine, so small clearance ( 0.3 mm- top piston ) for 2618 aluminum, oil fuel ratio 1 to 200) So with Ns cylinder all ended just starting the tests.

Made new piston 58 mm.- 1 mm bigger than NS ( 133 cc) and rygerised Honda Cr 125 1986 cylinder ( very different from NS - Good thing is bigger reed cage with six petals, wrong things two exhaust windows and iron sleeve) Again the power no more than 20-25 Hp

Then made plate to close central intake window, just left side intakes to transfers. Power up to around 30 hp but no more and very clean carburation at top.

Then exhaust stinger increased from 23 to 29 mm. and again power little bit up, but with more retarded ignition. Take of intake window plate, power drops insignificantly.

Then decided to lower compression from 13.8 to 12.5 and results feels immediately, is like 10 hp added. Added 23 mm sleeve to 29 mm stinger but no big difference just feels more tension . Of course this is only my sensations, but in comparison with other motorcycles now I think power is 35-40 Hp. I feel sorry that not lowering compression on the first NS cylinder (compression was 14) before seize, and just left only consideration.

From mechanical side no issues (most surprises for me after seize ), steel tube and small aluminum cylinder good pair ( just small scratches from some sand particles or something) and the PTFE seal amazingly in good shape.

There is so much other things left to try its very complex and so much different combination exists. Now I think that Ryger type engine with clever people can achieve 60-65 Hp


I'll post pictures later and more detail info.

[F5 Dave]

Thank you for reporting very interesting.

[adegnes]

Thank you for reporting very interesting.

+1

.................

[TZ350]

Yes, very interesting.

[TZ350]

page 1760 .....

[chrisc]

Thanks or the flowers Chris. You are right, the duct was machined and the sleeve was pressed in. The cylinder isn't mine, it belongs to my friend Jan Schäffer (the German giant who wins 50 cc races). He is quite open about his engines and chassis, but he publishes most of his work on a closed forum, so I do not feel at liberty to show much of it here. But you may find some info on his company website https://langtuning.de/Shop2/Startseite-1 and on http://www.simson-rennteam.de

Thanks Frits, appreciate it. I remember his cool racer you showed us! He might be able to help me source a decent crank for this SX50 so I'll send him an email anyway, because I can only find the million dollar VHM option :scratch:

[philou]

the clearance between the piston and the cylinder must be decreased with the avgas compared to the unleaded

Can you explain ?

[Frits Overmars]

... decided to lower compression from 13.8 to 12.5 and results feels immediately, is like 10 hp added. Thanks again Katinas. When are you going to lower the compression ratio to 8 or 9 ? (I'm only partly joking :rolleyes:).

[peewee]

The B transfer inner duct radius is very square and unlike the teacup shape which has been recommended. The A transfer duct inner radius is comparatively much better although has a flat in the middle of the 2 radius.

the flat your talking about seems common with ktm. the 250 and 300 is the same way on both A and B. you can make your own teacup with epoxy but then youll need to grind the outer wall to match and that may require some welding on the exterior depending how large the inner wall radius is

[peewee]

Had the carb apart again to drill out anything I couldn't fit my thumb through.
I drenched everything in brunox(wd40 equivalent) after running it, but forgot to do the float chamber.
No residue or anything, but that smell! I can best describe it as week old dead rodent.

have you got this engine running good yet ?

[adegnes]

have you got this engine running good yet ?

It's been sitting untouched since modifying the carb, but I started working on it again a few days ago.
Confirmed that jetting was far too rich, It would start, but die within seconds, or by touching the throttle. I've returned to a stock needle jet but haven't had an opportunity to test it again yet. Let's hope the 1.5mm pilot is enough to quench its thirst at low throttle openings.
There's a video coming soon on my channel, stay tuned!

[peewee]

It's been sitting untouched since modifying the carb, but I started working on it again a few days ago.
Confirmed that jetting was far too rich, It would start, but die within seconds, or by touching the throttle. I've returned to a stock needle jet but haven't had an opportunity to test it again yet. Let's hope the 1.5mm pilot is enough to quench its thirst at low throttle openings.
There's a video coming soon on my channel, stay tuned!

I saw the other video which appeared the carb wasn't providing enough fuel. wasn't sure if you had it sorted out yet. it looked like you were using a gravity flow from the tank. will the flow through the float valve be enough for full throttle ? the main thing im wondering is if com ratio needs to be lowered as im at 16:1 for straight methanol and don't know if this is already to high for even small percent nitro. I think it was bells book that said even methanol may work better with lower com ratio which is opposite of what a lot of people say so it isn't making sense to me.

have you seen any corrosion damage to rod or main bearings ? have the crank seals melted away or their fine ? I didn't see your engine exploded so the pickled cases must be a wives tale ?

[Norman]

Hi,

Sorry for so long time without info, but just want to test as more as I can before say something.

Now just current results without details :

Done about 500 km.

Testing three different types of cylinders ( two from Honda NS, and last from Honda Cr 125 86") and three different types of pistons.

Very interesting, so different type, but result was the same. The power feels like 20-25 Hp, no more. Power band 8600-11500 rpm. ( harmonizes with pipe dimensions). It revs, but feels that engine want to overcome something.

First piston heavily seized in second gear at 100 km/h, but luckily left hand remember old habit ( absolutely my fault, cold engine, so small clearance ( 0.3 mm- top piston ) for 2618 aluminum, oil fuel ratio 1 to 200) So with Ns cylinder all ended just starting the tests.

Made new piston 58 mm.- 1 mm bigger than NS ( 133 cc) and rygerised Honda Cr 125 1986 cylinder ( very different from NS - Good thing is bigger reed cage with six petals, wrong things two exhaust windows and iron sleeve) Again the power no more than 20-25 Hp

Then made plate to close central intake window, just left side intakes to transfers. Power up to around 30 hp but no more and very clean carburation at top.

Then exhaust stinger increased from 23 to 29 mm. and again power little bit up, but with more retarded ignition. Take of intake window plate, power drops insignificantly.

Then decided to lower compression from 13.8 to 12.5 and results feels immediately, is like 10 hp added. Added 23 mm sleeve to 29 mm stinger but no big difference just feels more tension . Of course this is only my sensations, but in comparison with other motorcycles now I think power is 35-40 Hp. I feel sorry that not lowering compression on the first NS cylinder (compression was 14) before seize, and just left only consideration.

From mechanical side no issues (most surprises for me after seize ), steel tube and small aluminum cylinder good pair ( just small scratches from some sand particles or something) and the PTFE seal amazingly in good shape.

There is so much other things left to try its very complex and so much different combination exists. Now I think that Ryger type engine with clever people can achieve 60-65 Hp


I'll post pictures later and more detail info.

Very interesting and good work! Looking forward to your pictures.
I have missed out the Ryger patent application from 08-02-17 with the number EP3128149 (A1). You can find it on google patents and some info at "https://register.epo.org/application?number=EP15179826&lng=en&tab=doclist".

It is an application, and not yet a granted patent, but I guess it is just a matter of time.
But, as always, the concept needs to meet the technical requirements and we have not yet received the full information on this. I am looking forward to the final confirmation of, not at least, the durability aspects.

[adegnes]

I saw the other video which appeared the carb wasn't providing enough fuel. wasn't sure if you had it sorted out yet. it looked like you were using a gravity flow from the tank. will the flow through the float valve be enough for full throttle ? the main thing im wondering is if com ratio needs to be lowered as im at 16:1 for straight methanol and don't know if this is already to high for even small percent nitro. I think it was bells book that said even methanol may work better with lower com ratio which is opposite of what a lot of people say so it isn't making sense to me.

have you seen any corrosion damage to rod or main bearings ? have the crank seals melted away or their fine ? I didn't see your engine exploded so the pickled cases must be a wives tale ?

It's sorted I think, I've made every fuel passage alot larger and started slowly working my way down from there.
I can't remember the exact number, but I believe I have sufficient flow through the float valve, it's drilled out to the absolute maximum allowable by the needle.

I'm at 14.5:1 and really have no clue if that works for the fuel. It's (by common belief at least) far too low for straight methanol, but with the nitro it's maybe not that far off.
We'll find out!

I have not noticed any damage, but it hasn't had much exposure to the nasty stuff yet.

No explosions, I don't think it's as bad as people want to believe. The nitric acid exhaust is tho.

[wobbly]

Regarding the bore clearance when running different egt levels Philou.
There is a finite amount of energy in each combustion cycle, and the combination of static + dynamic compression + the ignition timing affects
the distribution of that energy.
Some goes into the water, some into the combustion process that heats the gas that then expands and pushes down the piston.

With high compression and or lots of advance - or both, a larger amount of this heat energy is transferred to the water , or is consumed very early in the combustion cycle thus when the Exhaust opens
there is less temp ( and by inference - energy ) dumped into the Ex port,then to the pipe.
With low com,or retarded ignition, there is still alot of energy available late in the combustion process as the piston cycles downward, that then can be used in the pipe.

The amount of heat energy transferred into the piston does not vary a huge amount, except when " normal " combustion is replaced by say ,detonation.
When this happens a vast amount of the available energy is used to create free radicals,that then initiate " knock " and we see the egt drop instantly when this occurs.
This energy distribution within a normal cycle is a completely different scenario to simply " running lean ".
Then of course the piston gets overheated,and it seizes in protest.
So in answer to the question, bore clearance isnt an issue even at 700*C as long as we have a "normal combustion " process occurring.

[Flettner]

So Wobbly, and all, how do we reliably and consistently promote detonation in the squish area? HCCI.
dont cool the squish area and have a taper that tightens up, leaving a volume around the annuls near the cylinder wall?
Have a squish area on the head that can be heated (controlled) to accurately set off combustion?<_<
Feed hydrogen into this annuls to promote ignition, methane perhaps?
I'm assuming a 'magic' piston that absorbs nothing, reflects everything and won't burn.

[Jannem]

Would there be any power to be gained from improved piston cooling in the exhaust side of a well developed modern 2-stroke? Directly or indirectly. I 'd suppose longevity at least if not hp.

Edit: Does the ex.port side of the piston run hotter than cooled ex.port adding heat to the intake charge returning from ex.port when on the pipe?

[Frits Overmars]

I have missed out the Ryger patent application from 08-02-17 with the number EP3128149 (A1). You can find it on google patents and some info at "https://register.epo.org/application?number=EP15179826&lng=en&tab=doclist". It is an application, and not yet a granted patent, but I guess it is just a matter of time. But, as always, the concept needs to meet the technical requirements and we have not yet received the full information on this. I am looking forward to the final confirmation of, not at least, the durability aspects.First, I'd like to make it clear once more that I am no longer involved in any way with the Ryger organisation, and haven't been since ultimo 2015 (but I am still bound by a non-disclosure agreement).
Here is the latest Ryger patent: 331576 It describes the engine but it does not give a clue about where the power comes from.

[katinas]

Thanks again Katinas. When are you going to lower the compression ratio to 8 or 9 ? (I'm only partly joking :rolleyes:).

Just remember your words about Germany 50 cc champion with 9 ratio. I will try
Sometimes its easy made wrong consideration when experimenting with high compression engines, because things that filling cylinder better ended with less power and opposite. Picture of seized first NS piston. Clearance top 0.3 mm, skirt 0.15 mm too small for 2618 alloy. Second piston made without clearance , then heated, turned, and when tool was 15mm from top, directed air stream to skirt. When piston cool down clearance on ring land 0.60 mm. skirt 0.25 mm. Its just experimenting, but very interesting to see the shape. On engine, up to now, works fine.

Thanks

[SwePatrick]

I´m still having big problems understanding how pumpvolume in that ryger('crankhouse pump') is going to have enough displacement to fill 124cc to above 100% VE as the exhaust wasn´t important anymore.

If the 'rod' has the same volume as an std twostroke connectionrod it might get close to the same pumpeffect(without pipe).
But now the rod seems to be about 20-30mm in diam(guessing low,, it might be up against 40mm also)
if having at 25mm rod it steals about 26.5cc in crankhouse pump displacement leaving only 98cc pump to fill 124cc cylinder.

And it seems like there is a 'buffervolume' in the lower part of the transfers, this still cannot be used if pipe isn´t important.

I would say the pipe is VERY VERY important to make use of that buffervolume.
It would also be one hell of an efficiant pipe as it is a quite small volume, the vaccum increases rapidly if no possibility to pull air though the carb.

Rgds

[katinas]

Very interesting and good work! Looking forward to your pictures.
I have missed out the Ryger patent application from 08-02-17 with the number EP3128149 (A1). You can find it on google patents and some info at "https://register.epo.org/application?number=EP15179826&lng=en&tab=doclist".

It is an application, and not yet a granted patent, but I guess it is just a matter of time.
But, as always, the concept needs to meet the technical requirements and we have not yet received the full information on this. I am looking forward to the final confirmation of, not at least, the durability aspects.

Thank you.

Second rygerised piston/cylinder type with Cr 125 barrel ( Honda CR 125 1983- 1986 and Honda NS 250/400 cylinders identical on crankcase) made like Ryger, with squash under piston and small cylinder top surface - 0,7 mm. But the power feels even lower than with previous seized type. I thought that when piston began moves up after BDC some vacuum in squash slowing down the piston. And then I made mistake, just eliminating squash (cut from piston). It feels little better on power, but now i think because weaker stream and filling works better with higher compression. Now, again I need made third new piston with bottom squash for much lower compression head.

[katinas]

I´m still having big problems understanding how pumpvolume in that ryger('crankhouse pump') is going to have enough displacement to fill 124cc to above 100% VE as the exhaust wasn´t important anymore.

If the 'rod' has the same volume as an std twostroke connectionrod it might get close to the same pumpeffect(without pipe).
But now the rod seems to be about 20-30mm in diam(guessing low,, it might be up against 40mm also)
if having at 25mm rod it steals about 26.5cc in crankhouse pump displacement leaving only 98cc pump to fill 124cc cylinder.

And it seems like there is a 'buffervolume' in the lower part of the transfers, this still cannot be used if pipe isn´t important.

I would say the pipe is VERY VERY important to make use of that buffervolume.
It would also be one hell of an efficiant pipe as it is a quite small volume, the vaccum increases rapidly if no possibility to pull air though the carb.

Rgds
This is just principal schematic.
With pipe when piston moves up , transfer windows open to under piston space and suction begun directly from carb, through big boysen type and transfer ports.
And that inertial stream at hight rpm become "one directional" and help when pipe is on and suck fresh mix directly from carb.
Very interesting once test my rygerised NS without pipe and it revs like with pipe, very different to conventional engine without pipe.

[SwePatrick]

Yes, it starts draw through carb when piston is moving upwards, i´m clear on that.
But pipe wasn´t important ryger stated.

I call b***s**t on that statement(from ryger), pipe still needs to be tuned ;)

Somehow IF this is the 'function', maybe the blowpulse into cylinder becomes so hard(due to high pressure in transfers) it creates a lowpressurepulse immediatly behind the highpressurepulse, like lowpressure behind a car traveling through air.
And by that accelerates the pulsesignal to the carb in an early phase before pipe pulls hard.
And thereby never lets the movement energy in incoming stream go down so low in amplitude.

[ranasada]

Regarding the bore clearance when running different egt levels Philou.
There is a finite amount of energy in each combustion cycle, and the combination of static + dynamic compression + the ignition timing affects
the distribution of that energy.
Some goes into the water, some into the combustion process that heats the gas that then expands and pushes down the piston.

With high compression and or lots of advance - or both, a larger amount of this heat energy is transferred to the water , or is consumed very early in the combustion cycle thus when the Exhaust opens
there is less temp ( and by inference - energy ) dumped into the Ex port,then to the pipe.
With low com,or retarded ignition, there is still alot of energy available late in the combustion process as the piston cycles downward, that then can be used in the pipe.

The amount of heat energy transferred into the piston does not vary a huge amount, except when " normal " combustion is replaced by say ,detonation.
When this happens a vast amount of the available energy is used to create free radicals,that then initiate " knock " and we see the egt drop instantly when this occurs.
This energy distribution within a normal cycle is a completely different scenario to simply " running lean ".
Then of course the piston gets overheated,and it seizes in protest.
So in answer to the question, bore clearance isnt an issue even at 700*C as long as we have a "normal combustion " process occurring.

so is better high diagram (low compression crankcase) and high ignition or low diagrams (high compression crankcrase) and retarded ignition?

[SwePatrick]

I say it´s better with a bit higher compression and getting exhaustheat with racefuel ;)

[breezy]

This is just principal schematic.
With pipe when piston moves up , transfer windows open to under piston space and suction begun directly from carb, through big boysen type and transfer ports.
And that inertial stream at hight rpm become "one directional" and help when pipe is on and suck fresh mix directly from carb.
Very interesting once test my rygerised NS without pipe and it revs like with pipe, very different to conventional engine without pipe.
,
Katinas, are you regulating the pressure in the crankcase or are you just venting it out to the atmosphere? i only ask as it states in the patent, increase of rpm by regulating the crankcase pressure either manually or automatically page 4/16 0042 of recent patent.( i did pose this question earlier but i think that the legal contract Frits is held under probably would not allow him to comment in any way on this .)

[breezy]

:brick::brick::brick::brick::brick:331591

hi Luc,,,

[peewee]

why doesnt somebody buy a ryger and we can see the mystery how it work with no more guessing :bleh:

something else i thought of a long time. if ryger work very well then why really nobody else is trying the same concept ?

[katinas]

,
Katinas, are you regulating the pressure in the crankcase or are you just venting it out to the atmosphere? i only ask as it states in the patent, increase of rpm by regulating the crankcase pressure either manually or automatically page 4/16 0042 of recent patent.( i did pose this question earlier but i think that the legal contract Frits is held under probably would not allow him to comment in any way on this .)

Posted sketch long time ago, on down stroke air out through reed valve and then only vacuum.

add some video https://www.youtube.com/watch?v=zZWVO1tDCtg

[marsheng]

A bit of 2 stroke history.

KR3 Proton.

https://www.youtube.com/watch?v=fYqhje4lvaY

Please excuse the accent. Do I sound that bad ??

Cheers Wallace.

[wobbly]

The tune of an engine is entirely dependent upon the fuel, and they are complete opposites.
Leaded racegas loves compression ( because you can ) and can be run very lean and retarded to get heat into the pipe.
Unleaded ( low octane by definition ) hates compression, loves advance and makes better power when run on the rich side.
One is not " better " than the other, just requiring a different approach to get the best result from the fuel energy available.

[Lightbulb]

I noticed a lot of back pulses through the carb at the lower rev range and vanished when it really came on.
It there any way to reduce these pulses ?
Compared to a standard engine, have you noticed any gains in the work you have been doing?
Neil

[Lightbulb]

HCCI or a derivative of it is the future of combustion. What style of combustion chamber shapes are being developed to take advantage of this new ideas.
Neil

[Martin1981]

if ryger work very well then why really nobody else is trying the same concept ?

maybe because it is NOT working very well?

[wobbly]

The problem with the whole sad Ryger saga is that from anyone's perspective anything and everything to do with it has been handled with such complete
incompetence that its now impossible to retrieve the situation.
They built 50 engines to comply with the CIK homologation,where are they - not one has been raced, anywhere.
We get screed after screed of bullshit from Luc, including graphs that anyone could make up of this version and that version - no signs anywhere of the real thing on a real dyno.
Then we get media reports of so called " happy distributors " , but still no actual reporting of an engine actually completing a race.
Luc comes on here promising to enlighten us on the detail, along with dyno "proof " he says he has.
i even deleted my posts on his crap approach to calling our collective intellect into question,on the basis of his promises.
What have we seen - nothing, and I know he has been on here many times, checking up on us, but still no proof.
Problem is that when you start from a public baseline of 70 Hp and 30,000 rpm from a 125, the only place to go is down the toilet, if its not shown conclusively to be true.
Im over the whole thing, sadly.

[husaberg]

The problem with the whole sad Ryger saga is that from anyone's perspective anything and everything to do with it has been handled with such complete
incompetence that its now impossible to retrieve the situation.
They built 50 engines to comply with the CIK homologation,where are they - not one has been raced, anywhere.
We get screed after screed of bullshit from Luc, including graphs that anyone could make up of this version and that version - no signs anywhere of the real thing on a real dyno.
Then we get media reports of so called " happy distributors " , but still no actual reporting of an engine actually completing a race.
Luc comes on here promising to enlighten us on the detail, along with dyno "proof " he says he has.
i even deleted my posts on his crap approach to calling our collective intellect into question,on the basis of his promises.
What have we seen - nothing, and I know he has been on here many times, checking up on us, but still no proof.
Problem is that when you start from a public baseline of 70 Hp and 30,000 rpm from a 125, the only place to go is down the toilet, if its not shown conclusively to be true.
Im over the whole thing, sadly.

It looks like luc is on line on this forum at the moment maybe he will share.....:whistle:
331603

Only if Wobbly change his rude words very fast, otherwise no chance !

https://www.youtube.com/watch?v=QoYiQ8Qsozk

[lucf]

This is just principal schematic.
Very interesting once test my rygerised NS without pipe and it revs like with pipe, very different to conventional engine without pipe.

Yes Katinas, that is right, the Ryger is not running on the pipe as normal with a twostroke.
And there is far more to tell, where nobody thought or wrote about till sofar !!
That is why Ryger is a different 2 stroke principle with new twostroke laws and proofs this is not "bullshit".
Also when I wrote that 30k is realy possible, but not advisible for a too easy breakdown and we succeed to make this lower.
Some little proofs about the mentionned powergraphic, (which nobody believes) wil follow.
Also the proof for a trackrecord will follow soon.

[wobbly]

HaHa Luc, my customers demand a result in 3 weeks to 3 months, is 3 years with no result to " soon ".

[lucf]

HaHa Luc, my customers demand a result in 3 weeks to 3 months, is 3 years with no result to " soon ".

Ýes Wobbly,
"follow soon" are the only words from me, which became afterwards not to be true, which I regret.
But anything else was 100%. So what do you think is most important Wobbly ?

[koenich]

But anything else was 100%
Can't see much else or may you enlighten me what I missed?

[lucf]

Can't see much else or may you enlighten me what I missed?

You will soon be very quit mr Koenich, like everone else with great words of bullshit and words like that.

[Grumph]

You will soon be very quit mr Koenich, like everone else with great words of bullshit and words like that.

That's not the response any of us here want to see. Honesty and transparency should be your aim from this point.

[lucf]

That's not the response any of us here want to see. Honesty and transparency should be your aim from this point.

Oh and I have to accept everthing they told me in the past? If so I stop now and you will have to search elsewere !!

[Tim Ey]

Back to Topic:


A bit of 2 stroke history.

KR3 Proton.

https://www.youtube.com/watch?v=fYqhje4lvaY

Please excuse the accent. Do I sound that bad ??

Cheers Wallace.

Which accent? I am struggling way more to understand certain dialects of my mother tongue :-).

Lovely machine! A real piece of art :-)

As you have them in your workshop, may you solve this riddle that occured to me:


Or one may combine it with the fullest opening of a Yamaha YPVS as presumably was done at Proton
331026
I can not imagine what the cigarette-box-alike attached to the YPVS will be otherwise.
Anyone got proof of my thoughts?

[koenich]

You will soon be very quit mr Koenich, like everone else with great words of bullshit and words like that.
this was a simple non offensive question but there you go again...

as I've already mentioned - I don't want this thing to fail but your PR (till today) hasn't done you any good. which even you seem to have noticed and yet still can't handle criticism.

[lucf]

Here is a new graphic real time measured and some proofs of the powergraphics which I published before.

https://www.facebook.com/luc.foekema/media_set?set=a.10207444870239010.1073741881.18054 54134&type=3&pnref=story

[Lightbulb]

without facebook

[F5 Dave]

I think Ijust did a fart that exceeded 71hp but at only 11900rpm. Can we calculate the bmfe?

[SwePatrick]

Here is a new graphic and some proofs of the powergraphics which I published before.

https://www.facebook.com/luc.foekema/media_set?set=a.10207444870239010.1073741881.18054 54134&type=3&pnref=story


Third party dyno?

Otherwise it tells us nothing.
I own a dyno, and if i want to scam people i can adjust parameters in dyno to get really 'fun' curves.
the only thing that happens in the long run is that i´m fooling myself.

So, question, how do you fill cylinder over 100% when pipe isn´t important?

Rgds,.

[wax]

I'm playing with a piston port cylinder at the moment which I have converted to a reed case engine. I have welded up the old intake and will now add a c port to the cylinder. I see some cylinders have two c ports where other ones have one. What the pro and cons of one or two. Thanks for the information you guys happily share on here

[41juergen]

I'm playing with a piston port cylinder at the moment which I have converted to a reed case engine. I have welded up the old intake and will now add a c port to the cylinder. I see some cylinders have two c ports where other ones have one. What the pro and cons of one or two. Thanks for the information you guys happily share on here

I would see some benefits for the larger/wider B ports when having only 1 (reasonable wide) C port. That supports high TA's for the overall transfers....
Am I right on my assumptions?

[lucf]

If for the benefits of power its not always the better. That depends on the combination with rpm and cilinder content, as well on bore and stroke.
You have to calculate before doing it in the blind.
https://www.facebook.com/notes/luc-foekema/hp-cc-comparison/4063702169994

[Frits Overmars]

I would see some benefits for the larger/wider B ports when having only 1 (reasonable wide) C port. That supports high TA's for the overall transfers....
Am I right on my assumptions?Yes you are.

[SwePatrick]

If being able to enlarge B-ports, go for it!
If not due to cylinderstuds etc etc go for bigger or more boostports.

Many many times tuning an engine is a whole lot of compromizes and one has to do the best of it.

More flow is more flow in the bottom end ;)

[jonny quest]

India is big into these single cylinder drag bikes. Their pipes feature really cool rainbow finish. I'm almost positive the pipes are made of Stainless steel.

Does anyone know how they're applying this finish to them? The blues look really good!

[breezy]

Posted sketch long time ago, on down stroke air out through reed valve and then only vacuum.

add some video https://www.youtube.com/watch?v=zZWVO1tDCtg

331617 item 54 pressure regulation of crank case

[wobbly]

Ha Ha again Luc, now you threaten us with not coming back on this board , well fucking great - you have contributed NOTHING to anyone's understanding of
a normal 2T,let alone any interesting Ryger operational info.

Re converting a piston port to reeds.
One trick is to weld in a bridge and use a boost port down each side.Combine this with oversize studs that are wasted
and you can make a huge intake port to support as much power as you want.
Here are some pics of a TZ250G cylinder with 58 stroke and 61.5 bore to run in a 350cc Classic LSR class on the salt.
Based on the work done for Eckerolds 350GP winning cylinder.
Over 100 Hp capable.

[wax]

That looks awesome wobbly.
Here is what I am doing at the moment. The studs get in the way of going for bigger b ports, the situation leaves me as only being able to make c ports. I was planing on two ports but if you think one bigger ones is better then I will go to that.

[wobbly]

So Luc, please now explain in plain English so us dummies understand.Why is it we have a graph of a KZ Vs a Ryger,when EVERY stock KZ engine I
have tested ( many ) make at least 45HP at 13,000 rpm peak.I dont see any numbers like those on this graph ?

[Michael Moore]

Photo #4 in wobbly's post above is in my garage when the final base decking was being done on my Tree/TOS CNC mill. Since Jeff is building two cylinders being able to swap them out on the fixture plate and push the button to do another one has been handy. I made the top and bottom spacer plates and we ran the same facing operation on the base surface after welding to get a datum surface so Jeff could determine the location for the final facing operation.

I suspect that Jeff is now not far from having a full work-week invested in welding on the two cylinders. It will be interesting to see how it runs.

cheers,
Michael

[jamathi]

So Luc, please now explain in plain English so us dummies understand.Why is it we have a graph of a KZ Vs a Ryger,when EVERY stock KZ engine I
have tested ( many ) make at least 45HP at 13,000 rpm peak.I dont see any numbers like those on this graph ?

We should now see Ryger engines winning races very soon.....
With at least half a lap advantage over the first KZ.
Because otherwise NO ONE will buy such an engine!
Of course, this may be another computer simulation trick.
We will see soon enough!
Or maybe we will have to wait 2 years again, who knows?

[katinas]

I noticed a lot of back pulses through the carb at the lower rev range and vanished when it really came on.
It there any way to reduce these pulses ?
Compared to a standard engine, have you noticed any gains in the work you have been doing?
Neil

Now its very similar to tuned standard, but no more ( around 35 hp)

0-3600 rpm - like std, maybe better

4000-7500 rpm - no power at all (much worse than std)

8000-8600 rpm - some signs of life, but with terrible noise ( first reaction was shut off everything, like huge detonation or exhaust gas to carb through C port )

8700-11500 rpm. - all become quite, just power

To stop back pulses, made plate to cover central intake window, but done this before lowered compression and before bigger stinger, power increase and this was first time that I feel real progress. After made 29 mm stinger, put off plate and power decreases little, but not like before. Then lowered compression and huge power increase. This is last test, so I do not know how engine will work with plate and lower compression. So this video done without plate, but with lower compression.

https://www.youtube.com/watch?v=zZWVO1tDCtg

[katinas]

Yes Katinas, that is right, the Ryger is not running on the pipe as normal with a twostroke.
And there is far more to tell, where nobody thought or wrote about till sofar !!
That is why Ryger is a different 2 stroke principle with new twostroke laws and proofs this is not "bullshit".
Also when I wrote that 30k is realy possible, but not advisible for a too easy breakdown and we succeed to make this lower.
Some little proofs about the mentionned powergraphic, (which nobody believes) wil follow.
Also the proof for a trackrecord will follow soon.

Thanks Luc for your replay, I want to clarify that I try it without pipe at all, and just with pipe header. Exactly with header it revs like with all pipe. Of course its static test and very short before "angry birds ".......



https://youtu.be/TB9PGPnSEtA

https://youtu.be/458kepm8QGk

[jellert]

Also the proof for a trackrecord will follow soon.

Let me guess, the track record at Eefde? Please do show us.

[lucf]

Thanks Luc for your replay, I want to clarify that I try it without pipe at all, and just with pipe header. Exactly with header it revs like with all pipe. Of course its static test and very short before "angry birds ".......

https://youtu.be/TB9PGPnSEtA
https://youtu.be/458kepm8QGk

Your welcome Katinas, you made a nice engine and will find out in step by step as we did in the past.
Sorry that it is a long way because a Ryger engine is not a normal twostroke, and many normal twostroke laws are complete the oposite, so that even so called "experts" can't understand.
That's why a Ryger can't be made easy in the right way and many attemps will end in a delusion.

When I got involved end 2008, after I made the 'out of the box FST engine', Ryger called me and I won't believe it too that this was something for me when looking for more power.
But after some time when the real power was a fact, I had no choise and starts to think about the principle and to find out were the power has to come from.
And found several details which are very important, of which the temperature in several ways is one of the most important, but sure not the only one.
All details, including the calculated data, will be described in the publication, which follows the moment Ryger is ready for it. No doubt Ryger time is coming !!

Kind regards
Luc

FST-twostroke-design https://www.facebook.com/notes/luc-foekema/fst-twostroke-design/4080202582494

And Ryger is not the only engine which doesn't need the pipe, read the text at this movie: https://www.youtube.com/watch?v=Yp91Ml5mxg0&t=32s

[jellert]

so called "experts"

People are called experts when they have real world results to show for it. The people here are experts, because they show real world results of their work. You don't get to call yourself an expert, your peers have to call you an expert. Writing some cryptic stories and repeating "you'll see!" is not the same as showing real results.

I'll explain why people keep asking for third party results, because you don't seem to understand. When TZ350 shows a dyno result people trust it, because he doesn't make bold claims and his results match or slightly exceed our expectations. When you show a dyno result, people don't trust it because you make very bold claims and imply that people like Jan Thiel and Wobbly are not experts. Naturally people are going to be sceptical when you say things like that, so they want to see results from an independent source.

A track record could be an independent source, so please show it and enlighten everyone.

[Lightbulb]

Thanks for the reply.
Have you tried a very long induction tract? Have you tried any anti reversion rings or steps?
Thanks,
Neil


Now its very similar to tuned standard, but no more ( around 35 hp)

0-3600 rpm - like std, maybe better

4000-7500 rpm - no power at all (much worse than std)

8000-8600 rpm - some signs of life, but with terrible noise ( first reaction was shut off everything, like huge detonation or exhaust gas to carb through C port )

8700-11500 rpm. - all become quite, just power

To stop back pulses, made plate to cover central intake window, but done this before lowered compression and before bigger stinger, power increase and this was first time that I feel real progress. After made 29 mm stinger, put off plate and power decreases little, but not like before. Then lowered compression and huge power increase. This is last test, so I do not know how engine will work with plate and lower compression. So this video done without plate, but with lower compression.

https://www.youtube.com/watch?v=zZWVO1tDCtg

[jamathi]

People are called experts when they have real world results to show for it. The people here are experts, because they show real world results of their work. You don't get to call yourself an expert, your peers have to call you an expert. Writing some cryptic stories and repeating "you'll see!" is not the same as showing real results.

I'll explain why people keep asking for third party results, because you don't seem to understand. When TZ350 shows a dyno result people trust it, because he doesn't make bold claims and his results match or slightly exceed our expectations. When you show a dyno result, people don't trust it because you make very bold claims and imply that people like Jan Thiel and Wobbly are not experts. Naturally people are going to be sceptical when you say things like that, so they want to see results from an independent source.

A track record could be an independent source, so please show it and enlighten everyone.

Yes, exactly my idea, an independent source which is credible...
After those ridiculous 70HP/30.000 rpm stories NOBODY believes you anymore!

[SwePatrick]

Now its very similar to tuned standard, but no more ( around 35 hp)

0-3600 rpm - like std, maybe better

4000-7500 rpm - no power at all (much worse than std)

8000-8600 rpm - some signs of life, but with terrible noise ( first reaction was shut off everything, like huge detonation or exhaust gas to carb through C port )

8700-11500 rpm. - all become quite, just power

To stop back pulses, made plate to cover central intake window, but done this before lowered compression and before bigger stinger, power increase and this was first time that I feel real progress. After made 29 mm stinger, put off plate and power decreases little, but not like before. Then lowered compression and huge power increase. This is last test, so I do not know how engine will work with plate and lower compression. So this video done without plate, but with lower compression.

https://www.youtube.com/watch?v=zZWVO1tDCtg

Honestly Katinas, no disrespect.
But your engine sounds really tired.
It seems like it need huge,,i mean HUGE increase of advance(ignition)

Rgds.

[SwePatrick]

So, question, how do you fill cylinder over 100% when pipe isn´t important?

Rgds,.

Avoiding my question Luc? (edit: i can see you are online at this very point when i posted this)

[Lightbulb]

LucF, that porting with exhaust over transfer was used in model plane engines from about 1952. It was used in the ED Racer 2.5cc Diesel engine. A small variation was made to the PAW diesel engines and they made a huge improvement in power output with a very small geometry change to both the exhaust and transfer ports. All these were called radial port engines. The schnurl port engines arrived in the late 60's and early 70's and basically the development stopped on the radial port engines. But in 2008 there was a change made to a PAW engine and was a real transformation. If they had done this back in 1967, which they could have done, the schnurl engines would not have been able to compete. Certainly comparing an early schnurl port to the radial port of 2008, the older schnurl would never have been able to win any races. On the same prop, the power/rpm increase is about 6500 rpm. So 15,000rpm to 21500 rpm.
Looking at your page linked above, it makes me want to be inclined to try making another ED sleeve with the PAW changes in the radial port engine and see what it will do.
Neil

[mr bucketracer]

Yes Katinas, that is right, the Ryger is not running on the pipe as normal with a twostroke.
And there is far more to tell, where nobody thought or wrote about till sofar !!
That is why Ryger is a different 2 stroke principle with new twostroke laws and proofs this is not "bullshit".
Also when I wrote that 30k is realy possible, but not advisible for a too easy breakdown and we succeed to make this lower.
Some little proofs about the mentionned powergraphic, (which nobody believes) wil follow.
Also the proof for a trackrecord will follow soon.Keep up the good work

[lucf]

LucF, that porting with exhaust over transfer was used in model plane engines from about 1952. It was used in the ED Racer 2.5cc Diesel engine. A small variation was made to the PAW diesel engines and they made a huge improvement in power output with a very small geometry change to both the exhaust and transfer ports. All these were called radial port engines. The schnurl port engines arrived in the late 60's and early 70's and basically the development stopped on the radial port engines. But in 2008 there was a change made to a PAW engine and was a real transformation. If they had done this back in 1967, which they could have done, the schnurl engines would not have been able to compete. Certainly comparing an early schnurl port to the radial port of 2008, the older schnurl would never have been able to win any races. On the same prop, the power/rpm increase is about 6500 rpm. So 15,000rpm to 21500 rpm.
Looking at your page linked above, it makes me want to be inclined to try making another ED sleeve with the PAW changes in the radial port engine and see what it will do.
Neil

Thanks Lightbulb,
If you read the whole story, than you see that many things became to me clear afterwards, but I didn't want to wait with publishing.
I also get one of those little 2.5cc engines from someboby from Belgium for my collection about this matter.
May be I will go on with it, but don't know if there will be time enough for it, because Ryger has my priority.



Keep up the good work

Thanks Bucketracer, you are brave to say this here on KiwiBiker.

Regards,
Luc

[jamathi]

Now they are making themselves ridiculous by having some of my posts on Dutch and Italian
websites deleted, shows they are very disturbed.....LOL
If they had a really good engine they would not have to be.
And I would not be writing as I do.....
In a way I really feel sorry.
But it was THEM that started shouting about 70HP/30.000 rpm, not me!
A big mistake......
And not my fault!

[lucf]

Now they are making themselves ridiculous by having some of my posts on Dutch and Italian
websites deleted, shows they are very disturbed.....LOL
If they had a really good engine they would not have to be.
And I would not be writing as I do.....
In a way I really feel sorry.
But it was THEM that started shouting about 70HP/30.000 rpm, not me!
A big mistake......
And not my fault!

Sorry Jan,
Yesterday I give you my hand and gave you more information than anyone else, but you still refuse.
So what can I say more, if you won't believe me, you in particular should have known me better ?
In 1968 my private Kreidler engine was as fast as your Jamathi. https://www.facebook.com/luc.foekema/media_set?set=a.3413567757040.109062.1805454134&type=3&pnref=story

We still can made the engine with 70hp and a max speed of 30k
But that is not the engine we want to sell, so after a long search we managed to get the result we published.

Regards,
Luc

[jamathi]

Sorry Jan,
Yesterday I give you my hand and gave you more information than anyone else, but you still refuse.
So what can I say more, if you won't believe me, you in particular should have known me better ?

We still can made the engine with 70hp and a max speed of 30k
But that is not the engine we want to sell, so after a long search we managed to get the result we published.

Regards,
Luc

Well, I wish you good luck with it....

Regards,
Jan

[koenich]

Luc, boosting his credibility since 2015 :facepalm:

[Jannem]

:o How do you accurately measure port timing heigths when you have radiused ex-port top and piston edge?

[Frits Overmars]

:o How do you accurately measure port timing heigths when you have radiused ex-port top and piston edge?I answered that same question here some time ago. Here is the corresponding drawing once more.
331628

[lucf]

Avoiding my question Luc? (edit: i can see you are online at this very point when i posted this)

Sorry, No answer in a climate were so many are shouting to me as if I 'm a bluffing dog !
For sure it is in the publication !

[Jannem]

I answered that same question here some time ago. Here is the corresponding drawing once more.
331628

Sorry for the repetitive question. I struggle to get meaningful results from searching and I'm only through reading the first 250 pages. Huge amount of information to absorb.

Thank you.

Edit:
In the same lines: Do you measure the deck height from the middle of the piston top radius? In practice, measure piston height from skirt to middle of the radius and do the port height measurements from the bottom of the liner against the skirt to get accurate reading from the caliper?

[Frits Overmars]

Sorry for the repetitive question. I struggle to get meaningful results from searching and I'm only through reading the first 250 pages. Huge amount of information to absorb. Thank you.You're welcome Jannem. I know it can be a quite a job to go through the lot here. Personally, I never seem to get along with any forum search function :p.

[philou]

Were the people who bought the first versions of the ryger refunded?

[jellert]

Sorry, No answer in a climate were so many are shouting to me as if I 'm a bluffing dog !
For sure it is in the publication !

As long as you have no independent results to show, it's called bluffing. I don't know about the dog part though.

Btw I just saw I was right about the track record, it was at Eefde. Such an important circuit in the karting world, lots of high level KZ drivers go there... :rolleyes:. What laptimes are you getting at Berghem, Genk or Kerpen for example? I mean if you're serious about competing with these engines you've surely tested at a proper track by now right? I'll go first: with a Rotax Max I went around Berghem in 46,28s a couple weeks ago, I guess KZ's are at least two to three seconds faster there. Here's a picture:
331650

Now you might be sceptical about that picture, because it could have been faked somehow. But the difference between your claims and mine is that mine is actually within expectation. People expect a good Rotax Max kart to do a laptime like that. If someone is still sceptical I don't start calling them names and say "you'll see"! I either provide more evidence or accept that this person doesn't believe me. See, it's not that difficult. Now it's your turn, what kind of laptimes do you get on a relevant track like Berghem? Or do you have plans to go testing there?

I'm not trying to tick you off, I'm just trying to explain WHY people here are sceptical and would love to see real world results that we can actually compare to.

[oldjohnno]

Sorry for the repetitive question. I struggle to get meaningful results from searching and I'm only through reading the first 250 pages. Huge amount of information to absorb

I know this has been mentioned here previously but just in case it's been missed: forum searches never seem to work but a google site: search usually gets results. For example, to search this thread for posts containing the word "ethanol" you'd type (or copy/paste) this:


site:https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner ethanol

[Lightbulb]

A 7 thou plastic shim at 45 deg is very close to 0.25mm and works very well on model engines. It is a thin strip about 1mm wide. Other times I use a 4 thou shim and sit it on the piston crown and poke it to the side of the ports. I do this on the induction timing as well with the 4 thou shim. And then compensate for the .1mm radial movement. With the MB engine I measure all from the centre of the crown, and use light to see the port. Seems to work quite good as well. Like everything, there is always a little bit of ambiguity around the timing numbers any way. It is good enough to get a comparison with.
Neil

[jamathi]

Were the people who bought the first versions of the ryger refunded?

No, nobody ever bought one....

[husaberg]

Sorry for the repetitive question. I struggle to get meaningful results from searching and I'm only through reading the first 250 pages. Huge amount of information to absorb.

Thank you.


The Kb search function needs a few paremeters spec'd
try this
First start from the ESE page to search the thread.
Then hit advanced search
Then search single content
Then Make sure the bottom dot is in post rather than thread.
331652

You can also select the author whose post you wish to search for instance Wobbly, Frits etc
by searching under their user name or multiple usernames.
this narrows down the number of posts to go through dramatically.

or you can use Google with a few key words that you are looking for but include "ESE works Engine tuner" you need " " the so Google only searches those words with the ESE thread.

[emess]

I use google custom search engine for looking up older items (items just posted don't show up directly)
https://cse.google.com/cse/publicurl?cx=009468122799118164990:5pd9xdluxce

This works really well.
I keep a tab open in my browser at this page

https://cse.google.com/cse/publicurl?

[breezy]

Sorry, No answer in a climate were so many are shouting to me as if I 'm a bluffing dog !
For sure it is in the publication !
Lucf,
i would imagine that you too are unable to speak openly about this engine due to legal implications which must be really frustrating for you as well as those who are interested. Its been such a long time since this engine was first spoken about, with great anticipation , many people have waited for how the engine works. Im sure i remember a statement about this being a design not for the big companies but for the 2 stroke community in general..... Thing is, governments bringing in laws which will eventually kill the 2 stroke/ 4 stroke whether it runs clean or not and industry which controls what we buy, now focusing on electrically operated engines time is running ever shorter. Cant Mr Ryger himself speak openly about his engine? whats holding him back?
regards, breezy

[katinas]

Honestly Katinas, no disrespect.
But your engine sounds really tired.
It seems like it need huge,,i mean HUGE increase of advance(ignition)

Rgds.

Yes, thats right. I started testing this engine with std advance, but then released that it needed much more ( 10-15 degrees, so surprised ). When made bigger stinger ( from 23 mm to 29 mm) found that much better power with std. advance, but from 0 to 6000 rpm. much worse. This video with std advance.

[Flettner]

Yes, poor Luc , between a rock and a hard place. I guess he is hamstrung as well, I just wish Ryger would hurry up and conker the world, or not, just do something!
It's almost too late now anyway.

[katinas]

Thanks Luc for your open words, yes this is very complex and after 3 month testing, sometimes, thought would be so nice return to std. engine.

Yesterday tested again:

Modified intake plate, cut hole for C port, and power was the best of all tests like ( 4-5 hp plus ) , but suddenly, when changing gear - BANG . Stopped, no compression, but easy rotating. Amazing, that happen at the same place where first piston seize in April. This time piston ring break down . So ......

[2T Institute]

Yes, poor Luc , between a rock and a hard place. I guess he is hamstrung as well, I just wish Ryger would hurry up and conker the world, or not, just do something!
It's almost too late now anyway.

Hardly too late in competition everyone wants the latest and greatest .................but got to have the runs on the board first. IF the engine lived up to the hype last years champ would be cutting laps around tracks with a mountain of youtube clips to look at.

[Haufen]

Luc, as said before by more than one person: it should be really easy for you to stop all this negativity regarding the Ryger.

Just make a public dyno fest at a third party dyno, open for everybody to attend if he or she wants to. Add to that some food, some beverages, maybe some music or even live coverage on the internet, maybe a piece of closed road for back to back test drives etc. And then test your engine against a KZ engine back to back, enjoy the result of 65 against 45 ponies in your favor, lean back with a big smile, open a beer and wait for the apologies and engine orders to overwhelm you.

Sounds really nice and easy, wouldn't it? So why don't you do it? My personal thinking is that you simply can't. And I wish you all the best that one day you will be able to. But until then, please try to view this Ryger thing from our perspective and do not get back to us until you have information that would be sufficient to convince yourself if you were not involved in the project.

Thanks.

[jamathi]

Luc, as said before by more than one person: it should be really easy for you to stop all this negativity regarding the Ryger.

Just make a public dyno fest at a third party dyno, open for everybody to attend if he or she wants to. Add to that some food, some beverages, maybe some music or even live coverage on the internet, maybe a piece of closed road for back to back test drives etc. And then test your engine against a KZ engine back to back, enjoy the result of 65 against 45 ponies in your favor, lean back with a big smile, open a beer and wait for the apologies and engine orders to overwhelm you.

Sounds really nice and easy, wouldn't it? So why don't you do it? My personal thinking is that you simply can't. And I wish you all the best that one day you will be able to. But until then, please try to view this Ryger thing from our perspective and do not get back to us until you have information that would be sufficient to convince yourself if you were not involved in the project.

Thanks.

Thanks Haufen, I could not agree more! Nothing more needs to be said! But the power is not really there, and I think this project will end on the scrapheap....

[lucf]

Lucf,
i would imagine that you too are unable to speak openly about this engine due to legal implications which must be really frustrating for you as well as those who are interested. Its been such a long time since this engine was first spoken about, with great anticipation , many people have waited for how the engine works. Im sure i remember a statement about this being a design not for the big companies but for the 2 stroke community in general..... Thing is, governments bringing in laws which will eventually kill the 2 stroke/ 4 stroke whether it runs clean or not and industry which controls what we buy, now focusing on electrically operated engines time is running ever shorter. Cant Mr Ryger himself speak openly about his engine? whats holding him back?
regards, breezy

Yes Breezy, You are right, but we can't give a sign to start if not everthing is 100% right. And that is what takes a long time.
And mr Ryger has no time to write here, because he has to use his time to made the Ryger production ready for selling all over the world, after publication.
He made longer days than everyone and I know.

Regards,
Luc

[lucf]

Thanks Luc for your open words, yes this is very complex and after 3 month testing, sometimes, thought would be so nice return to std. engine.

Yesterday tested again:

Modified intake plate, cut hole for C port, and power was the best of all tests like ( 4-5 hp plus ) , but suddenly, when changing gear - BANG . Stopped, no compression, but easy rotating. Amazing, that happen at the same place where first piston seize in April. This time piston ring break down . So ......

Yes Katinas, it is not so easy as many people think. We have faced also many problems.
Most people we know, who have tried till sofar has stopped the attempt.

Sorry I can't be more open !!

Regards,
Luc

[lucf]

First Ryger trackrecord verified by Eefde: http://kartingeefde.nl/karten

Next step: winning race
Next step: publication

Regards, Luc

[Vannik]

Yesterday tested again:

Modified intake plate, cut hole for C port, and power was the best of all tests like ( 4-5 hp plus ) , but suddenly, when changing gear - BANG . Stopped, no compression, but easy rotating. Amazing, that happen at the same place where first piston seize in April. This time piston ring break down . So ......

Katinas,

In simulation of what I think the Ryger is it seems to need a much stiffer reed valve petal. Typically 0.20 to 0.25mm thicker than what is typical for a 125cc engine (0.40mm glass fiber), so use 0.60 to 0.65mm. Just a suggestion. And it does not seem sensitive to a tuned pipe.

Vannik

[katinas]

Katinas,

In simulation of what I think the Ryger is it seems to need a much stiffer reed valve petal. Typically 0.20 to 0.25mm thicker than what is typical for a 125cc engine (0.40mm glass fiber), so use 0.60 to 0.65mm. Just a suggestion. And it does not seem sensitive to a tuned pipe.

Vannik

Thanks very much Vannik, when I read this, just remember what I forgot to tell.
When start tests with Rygerised Honda Cr 125 86 cylinder with 6 petal cage, first install original carbon reeds and stoppers from Cr 125 2006, and later install glass fiber reeds and stoppers from Cr 125 1986. Reeds nearly same thick ( 0,43 mm), but stoppers very different shape with rubberized surface without holes. When open with finger it feels stiffer than 2006.
On the road from 9000 rpm I feel new power kick, and from that point until yesterday not experimenting with other reed petal.
And now, after failure with ring, I can try thicker reed just when made new piston and head.
I always testing all two strokers on the same 3 km road section deep in the forest, about 20 years, so sensations about power are sharp. But I have one rule, never compare day and evening tests results, because evening forest oxygen is fantastic thing....

[katinas]

Remember one test with first piston and Rygerised Ns 250 cylinder with sleeve from my racing days.

Raised boost windows, halfway between Ex open and main transfers open. Started and it feels very different, something very reactive, and little more revs.
Outside was cold April rain, so I cant test on road and decide to rise even more, just 1 mm after Ex open. Started it and immediately feel engine laziness. It revs, but not fast as before. On the road was slow acceleration with terrible noise. But maybe without pipe would be different. So feel sorry, that not tested with with halfway boost.
Piston in photo from std. engine, just for better view

[Jannem]

They say the second thing to go is the memory, and I can't remember what the first thing was.

:lol:

I still remember. It's the eyesight.

The eye extensions double up as protection from chips fortunately and you never forget them... However, sticking your head up close to see when grinding miniature cast iron pot leads to some intersting findings later if you forget the respiratory mask. As you say, the memory is the next.

Now, where did I put down that grinder??:pinch:

[Haufen]

I always testing all two strokers on the same 3 km road section deep in the forest, about 20 years, so sensations about power are sharp.

Sounds to me like you are the ideal candidate to use one of the freeware road dynos available on the net. Some even allow for temperature and ambient pressure correction, which gives results almost as accurate and repeatable as a real dyno (once the vehicle has been calibrated, otherwise it's just qualitative, but nevertheless repeatable). This way, you (and we) could gain much more insight about the effect of your engine modifications. The electronics needed are not really complicated and can be bought / modified for cheap and rather quickly as far as I remember.

What do you think? If you're interested, I am sure someone around here can provide a link and / or documentation of such a system.

[peewee]

hey guys im making the swingarm longer by 5". im not much experience in structure design but heres my idea. i was thinking on all seams to be welded, ill chamfer the edges to a V, then put a root pass with about 120hz and medium size filler. then a pass over the top at 60hz and large size filler. what do you think ?

[Haufen]

hey guys im making the swingarm longer by 5". im not much experience in structure design but heres my idea. i was thinking on all seams to be welded, ill chamfer the edges to a V, then put a root pass with about 120hz and medium size filler. then a pass over the top at 60hz and large size filler. what do you think ?

I like to be on the safe side with things like that, so I would do the elongation piece more or less as described by you, but I would never do that without an inner part which reaches at least 10cm / 4 in into both sides of the original swingarm (shape the same as the swingarm, only a bit smaller so that it just fits in). This inner piece would then be welded to the original parts at about 3 inches inside (2x 10mm holes into the original part only) and at the junction of the original part and the elongational part you would make a V where at the ground of the vee you could see the inner part. Then weld everything together taking care that the parts do not distort too much.

[peewee]

I like to be on the safe side with things like that, so I would do the elongation piece more or less as described by you, but I would never do that without an inner part which reaches at least 10cm / 4 in into both sides of the original swingarm (shape the same as the swingarm, only a bit smaller so that it just fits in). This inner piece would then be welded to the original parts at about 3 inches inside (2x 10mm holes into the original part only) and at the junction of the original part and the elongational part you would make a V where at the ground of the vee you could see the inner part. Then weld everything together taking care that the parts do not distort too much.

yes the extension piece will insert 2" into the existing swingarm at each end. I figure that is plenty strong as the bike isn't for motox but just drag racing with no jumps. I could make it insert 3" as I haven't yet machined the extension

I see what your saying about the holes. drill holes through the existing arm and weld the extension piece to the swingarm via the holes

[WilDun]

A true enthusiast like Katinas doesn't need external equipment to figure out what is right, wrong, good or bad! and he has a good internal hard drive in his head to draw his info from......but what will happen to all that precious info when (if) the hard drive packs up? - our loss! :facepalm:

[oldjohnno]

Sounds to me like you are the ideal candidate to use one of the freeware road dynos available on the net. Some even allow for temperature and ambient pressure correction, which gives results almost as accurate and repeatable as a real dyno (once the vehicle has been calibrated, otherwise it's just qualitative, but nevertheless repeatable). This way, you (and we) could gain much more insight about the effect of your engine modifications. The electronics needed are not really complicated and can be bought / modified for cheap and rather quickly as far as I remember.

What do you think? If you're interested, I am sure someone around here can provide a link and / or documentation of such a system.

Trouble is there is a wide variety in the size of horses and this requires the use of correction factors, eg:

Actual dragstrip verified horsepower = 1:1
American horsepower = hp x 1.25
Pub horsepower (<5 beers) = hp x 1.5
Pub horsepower (>5 beers) = hp x 3
Magazine project bike horsepower = hp x 1.3
Ryger horsepower = ????????

[peewee]

haufen let me ask something about the extension. on each end where its machined down to fit inside the arm. the machining will produce sharp inner corners. do you think i should make these inner corners have a small radius instead or it isnt critical ? i always thought a crack can form at sharp corner but maybe this situation isnt a big deal. cheers mate

[jamathi]

First Ryger trackrecord verified by Eefde: http://kartingeefde.nl/karten

Next step: winning race
Next step: publication

Regards, Luc

A lap record on a track where no races are held has very little meaning....
The last 'record' was made in 2011, as everyone can see.
Improved by 0,3 seconds
And KZ's are not even permitted at that track.
So they beat a RENTAL kart record......
Incredibly ridiculous!

[jellert]

A lap record on a track where no races are held has very little meaning....
The last 'record' was made in 2011, as everyone can see.
Improved by 0,3 seconds

Exactly, I could go to Eefde with a decent kart and spend days refining the setup to see what laptime I can get. But the track is so tiny and irrelevant that it would be a waste of time and money. We will probably never see a laptime to compare this with, because no KZ driver wants to go to a Mickey Mouse track where no races are held.

[Peter1962]

Sounds to me like you are the ideal candidate to use one of the freeware road dynos available on the net. Some even allow for temperature and ambient pressure correction, which gives results almost as accurate and repeatable as a real dyno (once the vehicle has been calibrated, otherwise it's just qualitative, but nevertheless repeatable). This way, you (and we) could gain much more insight about the effect of your engine modifications. The electronics needed are not really complicated and can be bought / modified for cheap and rather quickly as far as I remember.

What do you think? If you're interested, I am sure someone around here can provide a link and / or documentation of such a system.

The power CDI system would give the repeatability you need for comparable runs, and it could also help in finding the best advance curve.
http://www.powercdi.com/en.html
Some explication by Fabio of his system can be found here : http://ktmtalk.com/showthread.php?535482-2017-Ktm-Husquvarna-2-stroke-jetting-ignition-testing-no-one-is-addressing
Go to posting nr 27 on page 3 for the info on the DPC.

[katinas]

The power CDI system would give the repeatability you need for comparable runs, and it could also help in finding the best advance curve.
http://www.powercdi.com/en.html
Some explication by Fabio of his system can be found here : http://ktmtalk.com/showthread.php?535482-2017-Ktm-Husquvarna-2-stroke-jetting-ignition-testing-no-one-is-addressing
Go to posting nr 27 on page 3 for the info on the DPC.

Yes this would be very helpful

Thanks

[Haufen]

haufen let me ask something about the extension. on each end where its machined down to fit inside the arm. the machining will produce sharp inner corners. do you think i should make these inner corners have a small radius instead or it isnt critical ? i always thought a crack can form at sharp corner but maybe this situation isnt a big deal. cheers mate

If you were to use screws only, then a radius would for sure be beneficial to avoid forming cracks. But as you are going to weld over it anyway, this should not be an issue, as it will be like one piece after welding. What's the wall thickness of your extension going to be?

[jamathi]

Vannik has done a Ryger simulation.
Very revealing!
Of course I will leave it to him to publicize the results here
Or you can look at 2Stroke.tech.com where you can already find them

[Vannik]

Jan is correct, I did a simulation of what I think a Ryger engine looks like. In the simulation I assumed good scavenging and good normal combustion. The layout is a stepped piston with the step smaller than the main piston, unlike the traditional stepped pistons where it is bigger than the main piston. The rest is just gas-dynamics and plenums. If this is close to the Ryger in its current format I do not know.

331683

[jamathi]

It will be very near I think.....
Thank you Neels!

[jamathi]

The whole story is a bit ridiculous after all the comments that were made in the past....
HCCI et all.
Now the scrapheap is waiting patiently!