[GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked)

Fab, do you want RSA blueprint to make your own copy? :)

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We did not flow the principal and secondary transfers separately.
In fact flowing the transfers makes little sense!
The important thing is more their direction and how
they influence upon each other.

Marc a écrit:: Fab, do you want RSA blueprint to make your own copy? :)

Marc, I am somewhat guilty of this situation. Fab asked these questions in a private message, but I requested him to ask them here, in the open. I get quite a lot of these kind of questions and I prefer to answer them here in public, so that everybody can benefit, instead of having to answer the same questions over and over again in private conversations.

@Fab: Jan Thiel has already made clear which questions deserve an answer. I can add that the best place for a lambdasonde is in the fat part of the pipe where it least disturbs the flow, and in the top side so that it does not get fouled by oil.
If that is not possible, then put it so far away from the cylinder that there is a pipe volume of at least twice the cylinder volume between it and the cylinder. That way you can be sure that the lambdasonde will not be fouled by unburnt mixture.

Thank you so much for answers and sharing experience and passion .

Just by curiosty how many liters / second do the transfer gives ?

@Ridley : you are right TFX ! Sorry Embarassed

@Marc : i have already the blue print :) but i do not want to copy i just want to understand more and more by passion.
No industrial purpose just can sleep with dreaming about 2stroke engines.You probably know what I mean.Sorry if i am too curious Embarassed

If I remember well the transfer flow was about 280 M/3 per hour with the port fully opened.
But this depends on the pressure used of course!
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the
crankcase and carburetter bellmouth because of the entering burned gasses.
This happens because with raising rpm. the pre-exhaust flow becomes insufficient.
When rpm raises still more there is no more transfer flow and the engine stops completely.
So transfer flow depends completely from what is 'allowed' by the exhaust flow!

We never used a lambda sonde.

Nombre de messages : 9 Localisation : italy Date d'inscription : 14/12/2010

Jan Thiel a écrit:: If I remember well the transfer flow was about 280 M/3 per hour with the port fully opened.
But this depends on the pressure used of course!
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the
crankcase and carburetter bellmouth because of the entering burned gasses.
This happens because with raising rpm. the pre-exhaust flow becomes insufficient.
When rpm raises still more there is no more transfer flow and the engine stops completely.
So transfer flow depends completely from what is 'allowed' by the exhaust flow!

We never used a lambda sonde.

Mr. Thiel then with a proper muffler if I understand it you can 'increase the discharge area beyond certain values and known gap???

thank you very much honored to write this post

Jan Thiel a écrit:: If I remember well the transfer flow was about 280 M/3 per hour with the port fully opened.
But this depends on the pressure used of course!
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the
crankcase and carburetter bellmouth because of the entering burned gasses.
This happens because with raising rpm. the pre-exhaust flow becomes insufficient.
When rpm raises still more there is no more transfer flow and the engine stops completely.
So transfer flow depends completely from what is 'allowed' by the exhaust flow!

We never used a lambda sonde.

Thank you so much for your reply.

Incredible story for this RSA engine , how many people worked on it ?

You told that it will be difficult to improve transfers in this cylinder; the injection and another point succeed in improving your last results ; do still want to work on it even if there is less competition?

What about Frits ideas like the exhaust with the spring (cf boat engines subject) or the 24/7 inlet even if it means a total reconstruction on the rsa engine ?

With your experience how do you see 2stroke developement ? Is there anything you would have tested and that you regret ?Perhaps a way to work when you began to search on these kind of engines ?
please tell us a story :)

king regards.

Most of the work was done by 3 people, at the Derbi racing department.

A variable tailpipe would certainly be something I would like to be tried!
And an injector in the crankcase.
But the development of this engine stopped in the beginning of 2008.
All the people who worked on it even do'nt work at Aprilia any more!

I am retired and live in Thailand!

Thank you Mr Jan Thiel.
It is very interesting.

Even your last sentence let us dreaming. :)

During all these years, did you work, at least once, with Olivier Liégeois and Gérard Petit, or never?

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Olivier Liégeois and Gérard Petit worked at Derbi the year before I came there.
I think they did a fairly good job and I would have liked them to stay.
Gérard emigrated to Thailand, later we heard he died there.

thanks for the answer Mr Jan Thiel .

Concerning the injector in the crankcase ; if i am not wrong , the "ktm" used this technic isn't it ?(Sorry I can't remember the creator"s name).

Even if the race is hard , you had conversation and ideas sharing with the other engine developers or each one were working "alone" ?For example , have you learned details about this "injector" from your "oponents" ?

Once again , thaks for all these details that make us dream.

King regards.

Each one was working alone.

Jan when you made a trial with a new pipe specification, was the trail with a mild steel pipe? Did you notice any difference when the pipe was then fabricated from titanium?

Jan lorsque vous faites un essai avec une spécification nouvelle canalisation, a été la piste avec un tuyau en acier doux? Avez-vous remarqué une différence quand le tuyau était alors fabriqué à partir de titane?

All experiments were done with steel pipes.
Titanium pipes were seldom used on the dyno!
But when we did I noticed no difference with steel pipes!
Of course the titanium pipes were a lot lighter.
The main disadvantage is you cannot repair them in the paddock!
Once an Aprilia pipe was welded in the Honda museum at Motegi.

Jan aside from the moving the disc valve to the rear of the engine was there another single change that allowed a big leap forward? In terms of HP or lower lap times, or was it just constant evolution of an already great design?

Je suis porté à croire qu'il y est entreprise que corrige titane canalisations paddock maintenant.

Jan a côté de la déplacer le disque valve à l'arrière du moteur a été qu'une autre seul changement qui a permis un grand bond en avant? En termes de HP ou moins circuits, ou était-il juste constante évolution déjà un grand dessein?

IOTS, please stop using the google translation tool, I can't stand laughing so much.
Keep posting in English, most of us read it more easily anyway.

aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 771973

aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 771973

Honte à toi Jarno, notre camarade Australien fait l'effort d'être compris par les non anglophones (ils sont nombreux) et c'est tout à son honneur aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 980796

aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 980796

ridley a écrit:: Honte à toi Jarno, notre camarade Australien fait l'effort d'être compris par les non anglophones (ils sont nombreux) et c'est tout à son honneur

:) Oui l'effort est louable mais je suis sur que même les non-anglophones comprennent mieux l'anglais que ça :

"Je suis porté à croire qu'il y est entreprise que corrige titane canalisations paddock maintenant.
En termes de HP ou moins circuits, ou était-il juste constante évolution déjà un grand dessein?"

Sans manquer de respect à notre camarade de l'Institut des Deux Temps aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 771973

Jan and Frits, do you think that, during last year, Marc Marquez engine has still been improved or was it a standart RSA?
And what about this year, the last one in GP?
And the last one: except you, is there some people able to go on your work on this engine?

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Dernier Moto Journal il y a un special 125 RSA d'occas...

Jarno a écrit:

ridley a écrit:: Honte à toi Jarno, notre camarade Australien fait l'effort d'être compris par les non anglophones (ils sont nombreux) et c'est tout à son honneur

:) Oui l'effort est louable mais je suis sur que même les non-anglophones comprennent mieux l'anglais que ça :

"Je suis porté à croire qu'il y est entreprise que corrige titane canalisations paddock maintenant.
En termes de HP ou moins circuits, ou était-il juste constante évolution déjà un grand dessein?"

Sans manquer de respect à notre camarade de l'Institut des Deux Temps aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 771973

I see why you laugh so much. I do the translation just as a courtesy. I have learned with my travels in the world that no matter how poor the attempt to speak a language, local people do appreciate the attempt.

Je vois pourquoi vous rire tellement. Je ne la traduction juste comme un simple courtoisie. J'ai appris avec mes voyages dans le monde qui n'importe comment les pauvres la tentative de parler une langue, la population locale ne apprécier la tentative.

lol!

Marc, Aprilia's two stroke engine development was stopped 2 years ago.
The people who did this work do'nt even work there anymore!
If you study the lap times in 125 they are about the same as they were 4 years ago.
At Brno the 125 lap record from 2003 has not been improved.
And at Valencia the lap record is from 2007 by Talmacsi on a RSW!
They are just using up the many spare cilinders from the 250's

There were no really big steps in the engine development, just steadily working on small improvements.

Institute of TwoStrokes a écrit:

Jarno a écrit:

ridley a écrit:: Honte à toi Jarno, notre camarade Australien fait l'effort d'être compris par les non anglophones (ils sont nombreux) et c'est tout à son honneur

:) Oui l'effort est louable mais je suis sur que même les non-anglophones comprennent mieux l'anglais que ça :

"Je suis porté à croire qu'il y est entreprise que corrige titane canalisations paddock maintenant.
En termes de HP ou moins circuits, ou était-il juste constante évolution déjà un grand dessein?"

Sans manquer de respect à notre camarade de l'Institut des Deux Temps aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 771973

I see why you laugh so much. I do the translation just as a courtesy. I have learned with my travels in the world that no matter how poor the attempt to speak a language, local people do appreciate the attempt.

Je vois pourquoi vous rire tellement. Je ne la traduction juste comme un simple courtoisie. J'ai appris avec mes voyages dans le monde qui n'importe comment les pauvres la tentative de parler une langue, la population locale ne apprécier la tentative.

lol!

We sure do appreciate your delicate intent, but unfortunately Google translator does not work well, at least between English and French so I doubt it's worth using it.

And again, no disrespect towards you in my comment.
My sincere apologies if you felt uncomfortable (or worse) with my post.

Famous Triumph dealer Jack Lilley once had the idea to turn his website into a fully international website relying on Google translator: an ad for a Triumph Speed Triple with belly pan and seat cowl became something like: "Triple de vitesse du triomphe avec poêle de ventre et vache de siège"...

Jan Thiel a écrit:: Marc, Aprilia's two stroke engine development was stopped 2 years ago.
The people who did this work do'nt even work there anymore!
If you study the lap times in 125 they are about the same as they were 4 years ago.
At Brno the 125 lap record from 2003 has not been improved.
And at Valencia the lap record is from 2007 by Talmacsi on a RSW!
They are just using up the many spare cilinders from the 250's

Thank you so much, Jan, to remember me that.
Here, in France, some reporters told that Marc Marquez engine was delivered each GP morning by plane (probably from a giant but secret headquarter, deeply hidden under a mountain in Finland)...

aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 809262

aprilia - [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 1) (Locked) - Page 24 809262

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» [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 3) (Locked)
» [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 2) (Locked)
» [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 5)
» [GP125] All that you wanted to know on Aprilia RSA 125, and more, by Mr Jan Thiel and Mr Frits Overmars (PART 4)
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