ESE's works engine tuner

[Peter1962]

Hi,

Started it yesterday and revs like like crazy chainsaw, I have never heard such a sound from this old engine. For this experiment made 1 cylinder crank, because Honda ns 250 engine is 2 cylinder. Ports timing and size is original . Cold winter outside and now no possibilities try on the road.
Thanks Harry R...

So now we have a non-official prototype of the Ryger design, maybe you can do what the Ryger crew did not : dyno it and publish the curve.

[jonny quest]

One more question for Jan. I'm still trying to figure out why the long rod was better for you. I personally don't think a longer rod is best for ALL applications. It does reduce the time the ports are open.

At which stage did you try it and find more power? Is it making more power from reducing side loading and friction? Or did it just move the piston out of the way at BDC for better flow?

[Flettner]

Yes.. but i still think there can be improvements.
Especially in roadracing.
An mx machine isn´t that sensitive like a hardcore tuned gp machine.

I was down at Link head quarters last week, we talked about using their system on a 125 or 50. They are sure it will work up to that frequency (injector pulsing). Finally their units are packaged in a small case so it may fit conveniently on a motorcycle. They are working on a unit to run direct injection injectors at the moment, interesting. You can run many different inputs into their ECU, yes MAP won't work on a twostroke as normal. But you can 'sample' the intake but only taking a measurement at a certain part of the crank rotation, useful. Link ECU will also allow a combination of MAP and TPS mix.
F9 not a hardcore GP machine? I think it might be a bit sensitive to that satement you are right, but never the less the old girl goes pretty nice for what it is, an EFI twostroke test bed.

[peewee]

Only 70HP front a twin 500? Ouch!

your statement cant be serious ?

[jamathi]

One more question for Jan. I'm still trying to figure out why the long rod was better for you. I personally don't think a longer rod is best for ALL applications. It does reduce the time the ports are open.

At which stage did you try it and find more power? Is it making more power from reducing side loading and friction? Or did it just move the piston out of the way at BDC for better flow?

I first tried it on a 50 cc in 1074: more power.
Going from 80 to 85
Then at Aprilia in 1996: more power.
Without varying the crankcase volume.
We went from 112 to 113 and 115, later 118 was tried, still better.
For the RSA we had to lengthen the connecting rod from 115 to 120 to improve inlet flow: more power.
It is mainly due to piston friction I think.
NSU already found this in 1953, piston friction was the main source of friction in their 250 4-stroke engine.
It may be different for a reed valve engine, I have not much experience with these.
But the piston friction loss will, of course, be the same in a reed valve engine.

Of course at BDC there is no difference as you have to adjust the cylinder height!
Maybe it is interesting that with a longer connecting rod I could use higher transfer ports on my 50.
Getting still more power!

The crankcase volume also changes, of course, unless you change the position of the piston pin in the piston, as we did at Aprilia
This can be better or worse....
You can change your crankcase volume in many ways.
But always keep in mind that flow is more important than volume.....
On rotary valve engines I found the bigger the better, within reason of course....
The Aprilia engines had very narrow crank wheels, (16mm) so a very big crankcase volume. About 660cc in TDC
A big crankcase volume makes very long inlet timings necessary.
And big carburetors.

This is probably the reason why reed-valve engines need a smaller crankcase volume.
The reeds 'decide' for themselves when to open...
They need some depression.
And because maximum inlet flow is probably determined by the reed block, big carburetors won't work on a reed-valve engine.
They just slow down the flow in the carburetor, making for a difficult carburetor adjustment.

So I think that a rotary valve engine will always give about 3-4 HP more (125cc) than a reed valve engine.
Because of its unrestricted inlet flow and less pumping losses.

[katinas]

Thanks Hooser,

Clearly Jan has a good eye for good 2 stroke ports..

Attachment 328305




OK Katinas, good post, BUT you have a lot of questions to answer:

1. To achieve the same port timings, did you use the same (ns250) con rod centres?
2. Did you retain the ns250 pipes?
3. Did you "wet sump" the crankcase?
4. How did you attach the piston rod (approx Ø35) to the cast (?) piston?
5. No con rod upper bearing shown. Was this a one sided thing (the pic) or is this just a mock up?

Certainly I (and I'm sure a shitload of others) look forward to understanding what you have done more. Well done though.

BTW, welcome to ESE.

Hi,

At the moment I can not say anything about the engine power characteristic and reliability, only passion as soon as possible to start the engine and to hear is it revs or ..... I never hear before so nice and powerful sound on this engine on full gas (at the moment this all I can tell, I do not have dyno all bikes test on the road). Bike not yet ready only naked chassis, engine, pipe (not full ready), ignition ,carb, wheels. No brakes and other stuffs.
When I started drawings (3 months ago) I begin to understand complexity that Ryger overcome (ex. assembling piston to conrod with that plate). Complete structure depends on how high can lift cylinder. On most motorcycle maybe 30mm is max, because no room in chassis. This is first dimension that you need to consider. And that means its impossible to use (ON MOTORCYCLE) original conrod (too long). Piston structure again depends on how high can lift cylinder. If piston is one peace aluminium, smaller piston can be coated or not. If coated (nicasil or something) seal ring is located in small aluminium cylinder (not coated). If small piston is not coated (cylinder coated or iron) , then seal ring must be on piston (aluminium wear out if seal located on cylinder) and must be lower than piston pin (higher than pin weakens small piston) and seal on the piston means long small cylinder and higher lifted cylinder. So for full aluminium piston, coated small piston is best selection, but Jan Thiel wrote, that Ryger had problems with coated piston.
Other selection is two or three parts piston. I do not have the possibilities to coat piston, so for me left this. It is possible to made three or more different construction. After made first piston, I release that is better options (lighter), but job is done test engine with that.

1. Plate thick 20 mm ( two peace - pate aw 2024, removable small cylinder Al-Si al4)
2. Piston 57 mm. tree parts ( aluminium parts from solid AL 2618, small piston tube CroMo hard chromed 38 mm.)
3. Cylinder 57 mm. Honda ns 400
4. Conrod Kawasaki KX100 (center to center 92 mm. big end 22x29 mm. small end 14x19 mm. .) but now i think KTM SX 85 conrod is beter center to center 96 mm big end 22x28 mm smal end 14x19 and looks stronger.
5. Crankcase with oil, but no sump no anything only conected through bearing with other cylinder crankcase space because this only experiment and if engine works then made two cylinder engine with sump.
6. Pipe is stainless handmade (one honda rs 125 copy other aprilia rsw 125 copy) both tested on normal engine
7. Carburetor Honda nsr 250 mc 28 tb 32 mm. Reed valve std. ns400 four petal.
8. Ignition Honda Rs 250 ND5 1985 (honda made racing ignition for this crankcase in racing version)
9. Combustion chamber 13.5 cc (with plug) squash 0.9 mm

[jamathi]

Very interesting, thank you for publishing this and not being so ridiculously secretive as Ryger.
They seem to have resolved their plating problems I heard some time ago.
They now declare 66HP at 13000 rpm.
But there is no power curve, so I think it is only a simulation....

[WilDun]

Not really involved in the discussion, but I just had to say very good effort, nice to see one about to be tested!

I was wondering who would be first to have a serious attempt at an actual "Ryger" clone (well close enough!) - I think there will be a few more "on the verge" of success! - then it'll be all on again and TZ's little thread will once more be swamped! :...................

[jonny quest]

I have a 125 dirt bike, and a dyno. Full machine shop too. I haven't studied the Ryger enough to build a prototype to test. But I would be willing if some people helped with what I would need to build this.

My engine is case Reed though. And I wouldn't want to go as far as modifying my cylinder for cylinder Reed. Just remembered that

[TZ350]

So the EFI reverse equivalent of an accelerator pump where it might lean off a bit when EGT drops below ideal for whatever revs. Maybe.

Yes good point, Ecotrons has a set of options where you get to define low, mid and high rpm speed ranges and an acceleration enrichment factor and deceleration enleanmeant factor for each range, default is 1.1 and 0.9 respectively but this can be changed.

The Ecotrons fuel maps are based on engine load which I guess is roughly transfer ratio for a 2T. And my new cylinder and injector layout required a new map but the gearbox broke before I got to finish developing it. I needed a fairly good map before I could properly test the overrun fuel cut option (problem) I discovered earlier.

Interestingly when Honda RS125's were on the dyno the drum would take ages to slow down on over run but my Beast would slow much quicker. After turning off the fuel cut option my Beast started to take much longer to slow down too. I am not sure if a Honda RS125 is meant to idle but if it is it would explain why it would take much longer to slow down on the dyno than my Beast did with its fuel completely cut off on over run.

I am looking forward to getting the Beast going again so I can explore those setup ideas you suggested.

[Flettner]

Hi,

At the moment I can not say anything about the engine power characteristic and reliability, only passion as soon as possible to start the engine and to hear is it revs or ..... I never hear before so nice and powerful sound on this engine on full gas (at the moment this all I can tell, I do not have dyno all bikes test on the road). Bike not yet ready only naked chassis, engine, pipe (not full ready), ignition ,carb, wheels. No brakes and other stuffs.
When I started drawings (3 months ago) I begin to understand complexity that Ryger overcome (ex. assembling piston to conrod with that plate). Complete structure depends on how high can lift cylinder. On most motorcycle maybe 30mm is max, because no room in chassis. This is first dimension that you need to consider. And that means its impossible to use (ON MOTORCYCLE) original conrod (too long). Piston structure again depends on how high can lift cylinder. If piston is one peace aluminium, smaller piston can be coated or not. If coated (nicasil or something) seal ring is located in small aluminium cylinder (not coated). If small piston is not coated (cylinder coated or iron) , then seal ring must be on piston (aluminium wear out if seal located on cylinder) and must be lower than piston pin (higher than pin weakens small piston) and seal on the piston means long small cylinder and higher lifted cylinder. So for full aluminium piston, coated small piston is best selection, but Jan Thiel wrote, that Ryger had problems with coated piston.
Other selection is two or three parts piston. I do not have the possibilities to coat piston, so for me left this. It is possible to made three or more different construction. After made first piston, I release that is better options (lighter), but job is done test engine with that.

1. Plate thick 20 mm ( two peace - pate aw 2024, removable small cylinder Al-Si al4)
2. Piston 57 mm. tree parts ( aluminium parts from solid AL 2618, small piston tube CroMo hard chromed 38 mm.)
3. Cylinder 57 mm. Honda ns 400
4. Conrod Kawasaki KX100 (center to center 92 mm. big end 22x29 mm. small end 14x19 mm. .) but now i think KTM SX 85 conrod is beter center to center 96 mm big end 22x28 mm smal end 14x19 and looks stronger.
5. Crankcase with oil, but no sump no anything only conected through bearing with other cylinder crankcase space because this only experiment and if engine works then made two cylinder engine with sump.
6. Pipe is stainless handmade (one honda rs 125 copy other aprilia rsw 125 copy) both tested on normal engine
7. Carburetor Honda nsr 250 mc 28 tb 32 mm. Reed valve std. ns400 four petal.
8. Ignition Honda Rs 250 ND5 1985 (honda made racing ignition for this crankcase in racing version)
9. Combustion chamber 13.5 cc (with plug) squash 0.9 mm

Good boy, thank you.
We are very interested.

[TZ350]

Fuel injection was tried, everybody was happy with how it performed on the dyno.
On-track it proved useless however.

500

The same injection was also tried on the 125. Same HP as with a carburetor. There was no injector in the crankcase.

I would have loved to have it on the 125!

I would love to know more about your experiences with fuel injecting a 2T. Things that particularly interest me are cylinder capacity, rpm and injector size and position, I would love to hear from anyone who has experience with 2T EFI.

Locally there are two 250cc MX bikes that I know of that have been successfully converted to EFI. They rev to about 9,000 rpm max and are reported to ride very well in the field. The late model YZ uses a single logical injector, made up of two physical injectors fired in parallel, vertically down, one in each B transfer. The Kawasaki Bighorn has the injectors in the crankcase firing horizontally, above and in line with the gap between the flywheels.

My 125 revs to 13,000 rpm max and uses two different size logical injectors. Swapping between them to cover the wider range of the changing time window for the injection cycle. I have found that the position and orientation of the injectors on my bike makes quite a difference and I would love to know more about your experiences, or anyone else's with 2T EFI.

Jamathi came back to me and told me that:-

"I never worked with it, the '500cc people' did. They told me it was fantastic. But the riders refused to ride with it: unrideable they said!"

Well "Fantastic" is encouraging "Unrideable" not so much.

I have heard of a local EFI RZ350, if anyone knows about this bike I would love to know more.

[katinas]

Hi,

Thanks for all replies, during the last four years Jan and Frits release so much brilliant 2 STROKE GP words (later led other open) and if someone collect all they posts from all forums, we should wonderful "2 stroke racing engines book". Thanks very very much.

Maybe, limited information about Harry Ryger engine, forced to act our brain more intensively, it is good in any case.

"Things that left unsaid" about "rygerised" Ns 250
1. Stroke is original 50.6 mm ( no room in 2 cylinder Ns 250 crankcase for 54.5 mm stroke, but for 3 cylinder Ns 400 crankcase its possible, because flywheel is bigger. Ns 400 is 93 mm Ns 250 is 86 mm. But again cylinder must be even higher. ) so with 57 mm. piston, engine is 129 cm3 X 2 259cm3

2. Difference between conrod center to center 17 mm. (Original Ns-250/400r conrod center to center 109 mm. Kx 100- 92mm)

3. Small piston tube length 80mm and radius cut to copy flywheel at BDC. When piston at TDC, small piston 29 mm remained in small clylinder. This is very important dimension (maybe first thing to decide before drawing) for piston stability and durability, longer is better, but again cylinder be lift up, its compromise . From all information that we found about Ryger engine, this dimension is between 10-20 mm. and maybe they the have problems, but maybe I am wrong.
From homologated drawings Ryger small piston dia. 36 mm. ( its minimal for 125 cc solid aluminium piston because no space for adequate strong conrod). For multi parts piston, like mine, minimal tube (with thread) dia. 38 mm. When made this, i release its critical. If tube be without thread, 37mm dia. be minimal.
Ryger piston suction ( 54/36x54.5mm) 69.3cc
Ns piston suction (57/38x50.6mm) 71.7cc

4. Especially important thing about Ryger consruction: all four planes ( crankcase, plate, cylinder) must be PERFECTLY parallel among themselves and PERFECTLY perpendicular to conrod and piston, small and big cylinder must be PERFECTLY in center. Its critical. When I screw one (of four) cylinder bolt, and try rotate crank, its stuck! In usual engine piston adjusts to cylinder. Imagine, when engine hot up and cylinder, like Frits wrote, becomes "banana" what can happen!! So, maybe any gasket under cylinder and plate not recommended. Best O ring or seal like bond 1104 .....
Ryger cylinder centered inside, Ns outside because no metal to centered inside. But exact pin is another solution
Of course this is old Ryger engine dimensions, and maybe they new engine is reliable and powerful.

[d2t]

Attachment 328296

I have to ask about the dual disc concept. If there are rotary discs on both sides of the crank (and I assume also carbs on either side), where will the output gear go? Seems like there would be some packaging issues.

[Michael Moore]

The Rotax rotary valve MX engines have the primary gear outside the rotary valve on the left side of the engine.