curious conrod dimensions

[Michael Moore-3]

I checked at Carrillo today and discovered they now have the 2009
catalog online, and they have their "Pro-A" rods for the various Japanese
and European 4T MX bikes listed now.

Something that surprised me as I looked at the dimensions was the
slight variance in the big end bores.

For example, the Honda,  Suzuki and Kawasaki 250s and Husky 610 all
have 38mm big end bearings.  But the bores are 38.001, 38.000, 38.011
and 38.011, with the Husky being the only one that is on size.  I see a
few other bores that are 42.000 and then 42.012 or 43.000 and 43.010.

I'd have thought that the bearings would have been a very standard
dimension.  Any ideas on why the manufacturers would vary these
slight amounts off of the nominal sizes?  Increasing a bore by .001mm
on the 250 Honda seems hardly worth the bother so maybe that was a
misprint and should have been .011 as on the Suzuki/Kawasaki 250s.  
Still, why wouldn't they use 38.000mm when the CRF450 uses 42.000?

cheers,
Michael

[Ian D-2]

>For example, the Honda, Suzuki and Kawasaki 250s and Husky 610 all
>have 38mm big end bearings. But the bores are 38.001, 38.000, 38.011
>and 38.011, with the Husky being the only one that is on size. I see a
>few other bores that are 42.000 and then 42.012 or 43.000 and 43.010.


OK, 0.001mm is negligible in any practical sense ( I'd guess the
manufacturing tolerance is more than that ), but 0.010 - 0.012mm
is getting into the region of designer "fit".  i.e. - the crank design
engineer prefers a little more clearance for the bearing.

The other possibility is that the crank pin is bigger,  i.e. - the
drawing tolerance spec is +/- on nominal rather than -/-.


Cheers          IAN


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[Michael Moore-3]

Hi Ian,

I thought to look at the inch column and that .001mm on the Honda
250 is a misprint as they show the same 1.4961" ID as for the Husky
610 at 38.000mm.  The Suzuki/Kawa 250 is 1.4965" for 38.011mm

The CRF450 is 1.6535"/42.000mm while the XR500 is
1.6540"/42.012mm.  Maybe the XR500 with probably both heavier piston
and longer stroke needs a skoosh more room to stay comfortable,
though the RPM on the XR is probably going to be lower than on the
CRF.

cheers,
Michael

[john fisher-4]

and of course the person who does the web site may not know a conrod from a walking stick, and not work directly for
carrillo either.

Michael Moore wrote:
> Hi Ian,
>
> I thought to look at the inch column and that .001mm on the Honda
> 250 is a misprint

[Michael Moore-3]

FWIW I just talked to a sales person at Carrillo and he said that a
custom length YZ250F (or similar) rod would still be a Pro-A with
carburized big end and the turn-around is about 8 weeks and $328 retail
price/rod.

I guess the demand for the MX rods has increased to where they are
more willing to do OEM-style hardened big ends instead of the inserted
race that used to be common on the roller bearing rods.

cheers,
Michael

[Julian Bond]

Michael Moore <mmoore@...> Mon, 26 Oct 2009 10:15:10
>I thought to look at the inch column

Er, can we just stop using imperial measurements for engineering work
please. We really don't want to lose another multi-million dollar
satellite.

But then an awful lot of engine work does seem to be still measured in
"thou". (and cigarette papers).

--
Julian Bond  E&MSN: julian_bond at voidstar.com  M: [phone]
Webmaster:          http://www.ecademy.com/      T: [phone]
Personal WebLog:    http://www.voidstar.com/     skype:julian.bond?chat
                         Relieves Chapped Lips

[GStarRon]

HI Mike...
 
Well imagine my surprise when I checked the hardness on my "off  shore"
carburized rod... the rod beam is 45RC, while the bearing surface was  25Rc...
small wonder it failed big time..  Give me the hardened steel  insert any
day..!
 
Cheers.!!
 
Ron
 
 
In a message dated 10/26/2009 10:51:43 A.M. Pacific Daylight Time,  
mmoore@... writes:

FWIW I  just talked to a sales person at Carrillo and he said that a
custom length  YZ250F (or similar) rod would still be a Pro-A with
carburized big end and  the turn-around is about 8 weeks and $328 retail
price/rod.

I guess  the demand for the MX rods has increased to where they are
more willing to  do OEM-style hardened big ends instead of the inserted
race that used to  be common on the roller bearing  rods.

cheers,
Michael


------------------------------------

Yahoo!  Groups Links

[Michael Moore-3]

Ron, is Carrillo farming out production on the Pro-A rods?  Or did you
have a different brand of rod?  

That's pretty strange that the bearing surface would be so much softer
than the beam of the rod.  I'd have thought at worst they'd be the same
(though still too soft on the bearing).

cheers,
Michael

[GStarRon]

Mike... oh my.. sorry if I gave the wrong impression. the bad  rod was NOT
a Carillo.. but an H-beam imitation, made for a Speedway  engine...   My
main point is that it is a very special technique to do  the flame hardening,
and if it is not done right, well all is lost... sooner or  later.  You need
about 60Rc for a bearing surface..  My new Carillo  Pro-A rod has the
hardened insert, and I expect it to last a lot longer and not  break in to bits...
 I really wanted an H-beam, but they did not want to  make it.  FYI,
Carillo is now owned by Pankl and some of the original  talent is gone... sigh..  
this month they are moving in with CP  Pistons (another related company) so
it may take longer to get  rods.    That said, due to the economy and all
that I got my new  rods in like 3 weeks, delivered.
 
Ron
 
 
In a message dated 10/26/2009 11:29:55 A.M. Pacific Daylight Time,  
mmoore@... writes:

Ron, is  Carrillo farming out production on the Pro-A rods?  Or did you
have a  different brand of rod?  

That's pretty strange that the bearing  surface would be so much softer
than the beam of the rod.  I'd have  thought at worst they'd be the same
(though still too soft on the  bearing).

cheers,
Michael


------------------------------------

Yahoo!  Groups Links

[Derek Capito]

Hi Ron,

I actually think the a-beam rod is a better rod than the h-beam, especially
for a roller bearing big end configuration like yours.

Regards,

Derek

motolab

www.moto-lab.com <http://www.moto-lab.com/>

-----Original Message-----
From: mc-engine@... [mailto:mc-engine@...]On Behalf
Of GStarRon@...
Sent: Monday, October 26, 2009 11:45
To: mc-engine@...
Subject: Re: curious conrod dimensions


Mike... oh my.. sorry if I gave the wrong impression. the bad rod was NOT a
Carillo.. but an H-beam imitation, made for a Speedway engine...   My main
point is that it is a very special technique to do the flame hardening, and
if it is not done right, well all is lost... sooner or later.  You need
about 60Rc for a bearing surface..  My new Carillo Pro-A rod has the
hardened insert, and I expect it to last a lot longer and not break in to
bits...  I really wanted an H-beam, but they did not want to make it.  FYI,
Carillo is now owned by Pankl and some of the original talent is gone...
sigh..   this month they are moving in with CP Pistons (another related
company) so it may take longer to get rods.    That said, due to the economy
and all that I got my new rods in like 3 weeks, delivered.

Ron

In a message dated 10/26/2009 11:29:55 A.M. Pacific Daylight Time,
mmoore@... writes:
Ron, is Carrillo farming out production on the Pro-A rods?  Or did you
have a different brand of rod?

That's pretty strange that the bearing surface would be so much softer
than the beam of the rod.  I'd have thought at worst they'd be the same
(though still too soft on the bearing).

cheers,
Michael


------------------------------------

Yahoo! Groups Links

[Ian D-2]

>My main point is that it is a very special technique to do the flame
>hardening, and if it is not done right, well all is lost... sooner
>or later.  You need about 60Rc for a bearing surface..


BE bores in rods shouldn't be "flame hardened", they should be
soft in the beam and around 60 HRC ( as you say ) in the BE
bore, to a depth of 1.00mm give or take.  The only way to do this
properly is "case hardening".


Cheers            IAN


See www.drysdalev8.com for :
- Drysdale 750-V8 Sports & 1000-V8 Cruiser
- DRYVTECH 2x2x2 Experimental
- Carberry Enfield 1000cc V-Twin
- Drysdale Hillclimb Open Wheeler

[DUKE MOTO SERVICES]

Talking of conrods.
Have any of you used, or have any comments/feedback on Falicon rods, for quality and longevity.

They do not use an insert in the big-end; stating that this avoids the risk of an insert coming loose, which should not be an issue if the insert is correctly fitted.

Isn't it better to use different steels for the rod beam and the big-end, due to their different requirements, so that you get the best case hardening steel for the bearing race and also the best steel for the strength of the rod beam?

Cheers, Noel.

[Ian D-2]

>Isn't it better to use different steels for the rod beam and the
>big-end, due to their different requirements, so that you get the
>best case hardening steel for the bearing race and also the best
>steel for the strength of the rod beam?


A good case hardening steel generally has very good core strength
too, all gear steels for instance.  I make my rods out of exactly that.



Cheers             IAN


See www.drysdalev8.com for :
- Drysdale 750-V8 Sports & 1000-V8 Cruiser
- DRYVTECH 2x2x2 Experimental
- Carberry Enfield 1000cc V-Twin
- Drysdale Hillclimb Open Wheeler

[hans_o_man]

> Isn't it better to use different steels for the rod beam and the big-end, due to their different requirements, so that you get the best case hardening steel for the bearing race and also the best steel for the strength of the rod beam?
>
Yes, of course it would be better to use e.g. a maraging steel (tensile strenth up to 3500N/mm² or 500.000psi)but that's quite expensive, and to utilize the high strength to a low weigth, you best would have to FE-construct it. (needs to have inserted a bearing race)
The use of a CroMoly non-case-hardening-steel won't bring any advantage over a CroMoly case hardenening steel.

cheers,
Hans

[DUKE MOTO SERVICES]

Derek,

Not that I disagree. Most OEM rods (and all the ones I have used), are 'A' beam, or similar and I've never seen a broken one that could be blamed on the beam shape.

Why do you think it is better, especially for a roller big-end?

Cheers, Noel.

--------------------------------------------------------------------------------


  ----- Original Message -----
  From: Derek Capito
  To: mc-engine@...
  Sent: Tuesday, October 27, 2009 4:52 AM
  Subject: RE: curious conrod dimensions


   
  Hi Ron,



  I actually think the a-beam rod is a better rod than the h-beam, especially for a roller bearing big end configuration like yours.



  Regards,



  Derek



  motolab



  www.moto-lab.com


  .

 

[DUKE MOTO SERVICES]

Thanks Ian & Hans,

This is one area of roller bearing rod design that I wanted to clear up because, one gets different opinions when the queston is posed; generally from manufacturers, who are making them one way one or the other.

So, Carrillo use a bearing sleeve and Falicon don't.
Most of the OEM rods, I have seen, don't either: Ducati, all the Japs, KTM, Husky, etc.....

I guess then, the only real advantages of each design is one has a replacable sleeve, when worn, instead of the whole rod and the other can save some weight and extra machining, by not having the sleeve. Although, the weight is rotational, rather than reciprocating, so is not a major problem. There is probably some cost difference also, due to the different manufacture.

Anyone had any dealings or have any info on Falicon??

Cheers, Noel.

--------------------------------------------------------------------------------

>Isn't it better to use different steels for the rod beam and the
>big-end, due to their different requirements, so that you get the
>best case hardening steel for the bearing race and also the best
>steel for the strength of the rod beam?

A good case hardening steel generally has very good core strength
too, all gear steels for instance. I make my rods out of exactly that.

Cheers IAN
See www.drysdalev8.com for :

--------------------------------------------------------------------------------

Yes, of course it would be better to use e.g. a maraging steel (tensile strenth up to 3500N/mm² or 500.000psi)but that's quite expensive, and to utilize the high strength to a low weigth, you best would have to FE-construct it. (needs to have inserted a bearing race)
The use of a CroMoly non-case-hardening-steel won't bring any advantage over a CroMoly case hardenening steel.

cheers,
Hans

[hans_o_man]

> So, Carrillo use a bearing sleeve and Falicon don't.
> Most of the OEM rods, I have seen, don't either: Ducati, all the Japs, KTM, Husky, etc.....
>
It's a cost factor. If you let make huge amounts of rods, you can save huge amounts of money by case hardening instead of inserting a hard ring, honing before and afterwards.

> I guess then, the only real advantages of each design is one has a replacable sleeve, when worn, instead of the whole rod
>
Yes, but if I look at yamaha SR500-rod BE, they nearly never wear. Only the SE does. There a bushing would be fine.
>
>the weight is rotational, rather than reciprocating, so is not a major problem.
>
I don't agree completely: A heavy BE stresses rollers and surfaces at high speeds.
>
> Anyone had any dealings or have any info on Falicon??
>
I always wanted to try one, I like the oval shaped beam, and the aerodynamic-theory behind :-) But its not soo easy to get one here in germany, they have no walk-in-shops or importeurs here. So please try it, and tell us.

Cheers,
Hans

[DUKE MOTO SERVICES]

I can see the cost factor and I have also seen the Yamaha reliability in their roller big-ends; they seem to go forever.
All weight adds stress, for sure.

I like the look and the theory behind Falicon's design also, which is why I am interested in their rods.
I also like Carrillo rods and their reputation is very good, but I have found them to be a bit difficult to deal with.
Falicon (and Carrillo) are not so easy to get here in Australia either, which is why I want to be as sure as possible, of their quality, before I get some made.
The rods I want, will be custom made and not from their stock items, so will be more expensive also.

If I get some made, I will let you know.

Cheers, Noel.


--------------------------------------------------------------------------------


  ----- Original Message -----
  From: hans_o_man
  To: mc-engine@...
  Sent: Tuesday, October 27, 2009 9:02 PM
  Subject: Re: curious conrod dimensions


    > So, Carrillo use a bearing sleeve and Falicon don't.
  > Most of the OEM rods, I have seen, don't either: Ducati, all the Japs, KTM, Husky, etc.....
  >
  It's a cost factor. If you let make huge amounts of rods, you can save huge amounts of money by case hardening instead of inserting a hard ring, honing before and afterwards.

  > I guess then, the only real advantages of each design is one has a replacable sleeve, when worn, instead of the whole rod
  >
  Yes, but if I look at yamaha SR500-rod BE, they nearly never wear. Only the SE does. There a bushing would be fine.
  >
  >the weight is rotational, rather than reciprocating, so is not a major problem.
  >
  I don't agree completely: A heavy BE stresses rollers and surfaces at high speeds.
  >
  > Anyone had any dealings or have any info on Falicon??
  >
  I always wanted to try one, I like the oval shaped beam, and the aerodynamic-theory behind :-) But its not soo easy to get one here in germany, they have no walk-in-shops or importeurs here. So please try it, and tell us.

  Cheers,
  Hans



 

[GStarRon]

Carillo will make rods both with and without the pressed in  race.  To get
a proper heat treat for a bearing surface takes a special  process, done
right it is OK, done wrong and oh well...  The rod is usually  copper coated
everywhere except where you want the heat treating... that is why  a lot of
rods are copper coated...  With a hardened steel insert you have  less chance
for error, plus you get a lot deeper heat treat and thus more  strength.
 
The "extra" weight in the big end means absolutely nothing to the  
bearings... what is hard on the bearings are detonation and of course the power  
stroke... what is hard on the rod (on a 4 stroke) is the overlap stroke when  
there is nothing pushing on the rod and you can get rod stretch.  The H  Beam
rod design is supposed to be superior in limiting rod stretch per  weight
of the (steel) rod.  (Or is that marketing  hype.?)
 
Keep in mind some of the OEM rods fail often in the big end  bearing...
seems like the Yami is better than most.
 
Ron
 
 
In a message dated 10/27/2009 4:02:27 A.M. Pacific Daylight Time,  
der_hiha@... writes:

> So,  Carrillo use a bearing sleeve and Falicon don't.
> Most of the OEM  rods, I have seen, don't either: Ducati, all the Japs,
KTM, Husky,  etc.....
>
It's a cost factor. If you let make huge amounts of rods,  you can save
huge amounts of money by case hardening instead of inserting a  hard ring,
honing before and afterwards.

> I guess then, the only  real advantages of each design is one has a
replacable sleeve, when worn,  instead of the whole rod
>
Yes, but if I look at yamaha SR500-rod BE,  they nearly never wear. Only
the SE does. There a bushing would be  fine.
>
>the weight is rotational, rather than reciprocating, so  is not a major
problem.
>
I don't agree completely: A heavy BE  stresses rollers and surfaces at high
speeds.
>
> Anyone had any  dealings or have any info on Falicon??
>
I always wanted to try one,  I like the oval shaped beam, and the
aerodynamic-theory behind :-) But its not  soo easy to get one here in germany, they
have no walk-in-shops or importeurs  here. So please try it, and tell  us.

Cheers,
Hans



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[Ian D-2]

>So, Carrillo use a bearing sleeve and Falicon don't.
>SNIP
>I guess then, the only real advantages of each design is one has a
>replacable sleeve, when worn


I guess it is just a corporate attitude, or maybe they also make
aluminium or titanium rods which need a sleeve and they carry
the design across their whole range ?


Cheers            IAN


See www.drysdalev8.com for :
- Drysdale 750-V8 Sports & 1000-V8 Cruiser
- DRYVTECH 2x2x2 Experimental
- Carberry Enfield 1000cc V-Twin
- Drysdale Hillclimb Open Wheeler