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 [GP 125 & 250] Why hydroforming is not as good as welded cones?

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AuteurMessage
GtG001



Nombre de messages : 81
Age : 64
Localisation : Adelaide, Australia
Date d'inscription : 03/06/2012

MessageSujet: Hydro Forming   Sam 14 Juil 2012 - 12:53

Hi Howard and others,
Thanks for the photos and tips on hydro forming.
I have hydro formed a few pipes but I could not get them consistently accurate. As you say, the amount of stretch needs to be controlled.
I noticed that you start with a rolled edge at 90 degrees before welding. That was the next thing I was going to try to allow the edges to fully form without tearing the welds. Originally, after welding the tears, I noticed that it formed better. From that experience, I now anneal the weld along the way to allow it to fully form without as much tearing but I am always looking for a better method.
Do you roll that edge or beat it over a dolly?
I use a pressure washer capable of 1800 psi and a manually regulator with a gauge from a hydraulic supplier. The regulator is at the outlet of the pipe and allows the water to flow through the pipe and the air to be bleed out before I close the regulator down. This allows the pressure to slowly increase for better control.

Can I ask what metal you use?
I use 1mm cold drawn steel sheet – not sure what the temper was but I look it up and post later.

Great topic, keep it going please.

Regards
Allan.


Dernière édition par GtG001 le Dim 15 Juil 2012 - 4:13, édité 1 fois
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Howard Gifford



Nombre de messages : 136
Age : 62
Localisation : Ottawa Canada
Date d'inscription : 01/05/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Dim 15 Juil 2012 - 2:19

I use 19 gage (.041") cold rolled steel ,nothing special.
I use a home made hand driven roller to roll the edge. I also use a small press that has an adjustable relief valve to allow the pipe to expand automatically in the press. The prssure setting depends on the size of the pipe . I press the pipe between two plates of steel covered with plywood. The press allows the entire pipe to expand evenly. Without it the center expands first and creates some horrible ripples. Everythin g is done cold. I do not recommend heating the pipe at all with any pressure in it.
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GtG001



Nombre de messages : 81
Age : 64
Localisation : Adelaide, Australia
Date d'inscription : 03/06/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Dim 15 Juil 2012 - 4:10

Hi Howard,
Thanks for the tip on the press – makes sense to restrict those areas when you hear it – a bit like squeezing one of those long thin balloons to get it to shape. In addition, the use of tube to restrict the belly is another good idea.
I had thought of making a Fiberglass mould for that purpose but it seemed too much work for the limited use it would get.
I think for my application, I will use both the hydro forming for the hard to make parts of the pipes and use rolled cones for the straight parts – at least until I can get the accuracy with hydro forming.

BTW - I never heat the pipe when it is pressurized, only after welding to anneal the metal.
Would you post a photo of the rollers you use as I would like to make one if that is all right with you.

For those of you looking for a cheap muffler, try here: [Vous devez être inscrit et connecté pour voir ce lien]
They make Carbon ones as well.

Regards
Allan.
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edu maccario



Nombre de messages : 1
Localisation : argentina
Date d'inscription : 17/08/2012

MessageSujet: escape artesanal   Ven 17 Aoû 2012 - 7:28

bonjour je suis de l'Argentine que j'ai 19 ans et j'aime les 2 à plusieurs reprises et je tiens à partager la photo d'une fuite qui fait ami sn.
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dcracing1



Nombre de messages : 2
Localisation : Vancouver, Canada
Date d'inscription : 10/09/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mer 12 Sep 2012 - 4:59

Late to the party as usual. I hydroformed the headers and rolled the cones for the last pipes I built. They're ugly as can be but perform well. Howard, the pipes you're hydroforming are absolutely beautiful.
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dutch fisher



Nombre de messages : 19
Localisation : England
Date d'inscription : 07/09/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 11:12

Frits Overmars a écrit:
I started writing my own physics programs around 1970, so over the decades it became quite a collection. They are not available to the public. Because I wrote them for personal use only, they are rather user-unfriendly and distributing them would cause an avalanche of questions that would completely rob what little time I have left; I would not be able to visit this forum any more Wink.

Frits, would you be willing to share the formula you use in your program to calculate the variation in crankshaft velocity in a single cycle

Regards
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Frits Overmars

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Nombre de messages : 2131
Age : 70
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 16:21

dutch fisher a écrit:
Frits Overmars a écrit:
I started writing my own physics programs around 1970, so over the decades it became quite a collection. They are not available to the public. Because I wrote them for personal use only, they are rather user-unfriendly and distributing them would cause an avalanche of questions that would completely rob what little time I have left; I would not be able to visit this forum any more Wink.
Frits, would you be willing to share the formula you use in your program to calculate the variation in crankshaft velocity in a single cycle.
Willing yes, able no. It is not a formula, it's a program. And for the answer to your next question: see above.
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Howard Gifford



Nombre de messages : 136
Age : 62
Localisation : Ottawa Canada
Date d'inscription : 01/05/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 17:29

Frits does the variation in rotational velocity amount to enough to upset the operation of the pipe or is it small enough to not worry about? having a twin cylinder made from similar cylinders usually use identical pipes to the single cylinder and a twin must have a lot less variation in crank speed.
We have a twin cylinder engine that is converted to run as a single in order to cut our development costs inb half. Usually the output of the twin is higher than two times the output of the single.
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Frits Overmars

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Nombre de messages : 2131
Age : 70
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 19:00

Howard Gifford a écrit:
Frits does the variation in rotational velocity amount to enough to upset the operation of the pipe or is it small enough to not worry about?
That variation is rather small to begin with. Furthermore it is a variation within a crankshaft revolution so the duration of a whole revolution is not noticeably affected.
Citation :
having a twin cylinder made from similar cylinders usually use identical pipes to the single cylinder and a twin must have a lot less variation in crank speed.
That depends; if you compare a single with a 180° parallel twin, the irregularity is almost identical; you can find some comparative graphs in the Big Bang topic if I'm not mistaken.
If you are talking about a 90° firing interval, then the difference is noticeable, but I never bothered to let it influence desired pipe behaviour.
Citation :
We have a twin cylinder engine that is converted to run as a single in order to cut our development costs inb half. Usually the output of the twin is higher than two times the output of the single.
I'm guessing here: I've seen that happen when both cylinders breathe through a common airbox. when each of them awaits its turn, they bot get more air.
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GrahamB

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Nombre de messages : 3457
Age : 56
Localisation : Lyon
Date d'inscription : 19/08/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 21:32

Frits Overmars a écrit:
Citation :
Usually the output of the twin is higher than two times the output of the single.
I'm guessing here: I've seen that happen when both cylinders breathe through a common airbox. when each of them awaits its turn, they bot get more air.

Frits, wouldn't that work the other way around? Ie the shared airbox would give less than double power, since the front cylinder in a V starts drawing before the rear has finished? It's interesting that Suzuki's RGV street-bike used a split airbox but Honda never bothered on the RS. And I've never had a chance to see an RSW250 airbox...

This might be a topic of interest for Francis, given the phasing of his motor...
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Frits Overmars

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Nombre de messages : 2131
Age : 70
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 22:00

GrahamB a écrit:
Frits Overmars a écrit:
Citation :
Usually the output of the twin is higher than two times the output of the single.
I'm guessing here: I've seen that happen when both cylinders breathe through a common airbox. when each of them awaits its turn, they bot get more air.
Frits, wouldn't that work the other way around? Ie the shared airbox would give less than double power, since the front cylinder in a V starts drawing before the rear has finished? It's interesting that Suzuki's RGV street-bike used a split airbox but Honda never bothered on the RS. And I've never had a chance to see an RSW250 airbox...
This might be a topic of interest for Francis, given the phasing of his motor...
For the functioning of the airbox a 180° twin would be best. Because the inlet phases are usually longer than 180°, the breathing of both cylinders would still get a bit in each other's way, so two separate airboxes would be better still, if you can find a place for them, but most of the time only one cylinder would draw from the large volume of a common airbox.
In a 90° twin (V or parallel won't matter in this respect) they are a bit more in each other's way. But in a twingle both cylinders would constantly be fighting each other for air. That may be one of the reasons that Francis has abandoned his airbox for now.
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fpayart

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Nombre de messages : 937
Age : 69
Localisation : LYON
Date d'inscription : 11/01/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 22:19

Just ask!

This is the last model :
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This is a little older model :
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[Vous devez être inscrit et connecté pour voir ce lien]
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[Vous devez être inscrit et connecté pour voir ce lien]
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http://www.fperacing.com/
fpayart

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Nombre de messages : 937
Age : 69
Localisation : LYON
Date d'inscription : 11/01/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 22:40

@ GrahamB,

Sorry Graham to the poverty of "my" English, I am not able to correctly translate your sentence: "This might be a topic of interest for Francis, Given the phasing of his motor ..."
If I use a translator, here's what I get: "Cela pourrait être un sujet d'intérêt pour Francis, Compte tenu de l'échelonnement de son moteur"

The two cylinders of our motor operate simultaneously, this means that the suction volume is a cubic capacity of 250 cc every 360 °
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GrahamB

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Nombre de messages : 3457
Age : 56
Localisation : Lyon
Date d'inscription : 19/08/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 23:32

Yes, I was trying to be obscure in case you didn't want to tell everyone

So I was thinking what Frits said: your two carbs are both sucking at the same time, so they are fighting each other for air in a small airbox...
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GrahamB

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Nombre de messages : 3457
Age : 56
Localisation : Lyon
Date d'inscription : 19/08/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 23:35

fpayart a écrit:
Just ask!



Et à l'intérieure, il n'y a pas de division entre les deux sorties d'air, les deux carbus tirent directement du même espace ?
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fpayart

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Nombre de messages : 937
Age : 69
Localisation : LYON
Date d'inscription : 11/01/2010

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mar 25 Sep 2012 - 23:43

Oui, voici la pièce qui se monte sur les carbus vue de l'intérieur
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http://www.fperacing.com/
Haufen



Nombre de messages : 55
Localisation : Allemagne
Date d'inscription : 23/12/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Sam 29 Sep 2012 - 20:06

Thanks for the pictures! Is there really a filter element that close to the carb bellmouth? Doesn't it get soaked from blowback fuel pretty quick?
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GrahamB

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Nombre de messages : 3457
Age : 56
Localisation : Lyon
Date d'inscription : 19/08/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Sam 29 Sep 2012 - 22:20

It looks like there is some very coarse foam there, but it would only be good for stopping rocks. Blowback would just save you from needing to oil the foam
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libbresse



Nombre de messages : 4
Localisation : Sweden
Date d'inscription : 02/04/2013

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Jeu 18 Avr 2013 - 22:48

Great looking pipes Howard Which cadprogram do you use when you make the templates ?

/Anders
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Howard Gifford



Nombre de messages : 136
Age : 62
Localisation : Ottawa Canada
Date d'inscription : 01/05/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Ven 19 Avr 2013 - 1:21

The templates are made "old school" on a drafting board. I make a centerline using an aluminum yardstick bent roughly the shape of the bend of the pipe and mark it off in 1 inch segments. I transfer the measurements from a full scale straightline drawing. I connect the dots with a flexible curve. I number each segment on both the template and the drawing and transfere the construction lines to the metal for future reference
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alwoodman1



Nombre de messages : 8
Localisation : Argentina
Date d'inscription : 24/04/2012

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Lun 9 Mai 2016 - 14:59

Muchas gracias a todos. Mi pregunta: ¿ cuál es la forma para evitar que la entrada al sistema no se cierre o se curve tanto?, Como no puedo subir fotos solo me registra el enlace, si alguno me hace el favor para ue se oueda ver el trabajo que hacemos.

Thank you very much to all. My question: what is the way to prevent the entry into the system is not closed or curve so ?, As I can not upload photos only records me the link, if any you please so you can see the work we do .
[Vous devez être inscrit et connecté pour voir ce lien] Yamaha RD 125cc

[Vous devez être inscrit et connecté pour voir ce lien] Zanella 125 (Minarelli)
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Riley Will



Nombre de messages : 54
Age : 46
Localisation : Calgary, Alberta, Canada
Date d'inscription : 14/01/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Lun 2 Jan 2017 - 6:44

Howard made a believer out of me on the 2 times he built pipes for BRC. First he copied our Type 21 pipe then he made pipes for our V2 prototype engine. He delivered exactly what we asked for. They are things of beauty too!
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http://www.brceng.com
Niels Abildgaard



Nombre de messages : 34
Localisation : Denmark
Date d'inscription : 26/02/2013

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Lun 2 Jan 2017 - 12:40

Riley Will a écrit:
our V2 prototype engine.
Can we have some news or pictures?
I am in love with 90 degree V2s with common crancase and common exhaust system.
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Riley Will



Nombre de messages : 54
Age : 46
Localisation : Calgary, Alberta, Canada
Date d'inscription : 14/01/2011

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Mer 1 Fév 2017 - 2:38

How do I post photos? Send me your email address and maybe you can post to me. [Vous devez être inscrit et connecté pour voir ce lien]
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http://www.brceng.com
Niels Abildgaard



Nombre de messages : 34
Localisation : Denmark
Date d'inscription : 26/02/2013

MessageSujet: Re: [GP 125 & 250] Why hydroforming is not as good as welded cones?   Jeu 2 Fév 2017 - 11:06

Riley Will a écrit:
How do I post photos?  Send me your email address and maybe you can post to me.  rwill@brceng.com
Hello Riley and thank You for remembering my question.Mailadress has been sent to Your mail.

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