New Conrods

lcrken · Mar 19, 2015

Xpongebob said:
Thanks IcrKen for these details, I admit I was really unaware of the multiple options Carillo offered.

Anyone having made a short stroke with these ?

There's quite a bit of detail on one of my short stroke 750 engines using them here:

short-stroke-750-build-t5490.html

Ken

jseng1 · Mar 19, 2015

Xpongebob said:
Thanks IcrKen for these details, I admit I was really unaware of the multiple options Carillo offered.

Anyone having made a short stroke with these ?

There should certainly be more short strokes winning races on the tracks in my opinion. Here is a photo of a regular short stroke Carrillo rod with bushed small end (photo from one of lcrKen's earlier posts). Small end weight of approx 138 to 142 grams I think.

Below is a photo of a bushless JS short stroke rod for DLC pins - small end weight of approx 106 grams and goes with 190 gram pistons.

Fast Eddie · Mar 19, 2015

hobot said:
I'm merely a parts user/consumer not a parts brewer pusher so ask how the seam is made in maddasses Slim Jim big end as can't see any evidence of it in photo. Cracked off caps is modern standard.

Cracked of caps is the modern automotive standard Steve you are right there. And when a cracked off cap is bolted together, the join is virtually invisible to the naked eye. Although, I have no idea if that applies to these!

Hobot · Mar 19, 2015

I don't think our Carello rods are cracked. I just can't seem to see a seam in maddasses so don't know if that step in yet to come or so close fit its invisible. I would think cracking at a finished stage may bend the roundness. Hope everyone sells all they can.

madass140 · Mar 19, 2015

no Steve my rods are not cracked, being shotpeened makes it harder to see the join, thats all.

madass140 · Mar 19, 2015

"Thanks Don, I run 63% in my race bike in an ISO frame"
Regards Mike
Well Mike I ended up with 62%.

jseng1 · Mar 20, 2015

madass140 said:
"Thanks Don, I run 63% in my race bike in an ISO frame"
Regards Mike
Well Mike I ended up with 62%.

I think you are right on with your balance factor.

Hobot · Mar 20, 2015

I once found & posted here somewhere the BSA race research on 360 vertical twins dry BF of 52% giving the lowest force spikes when oil filled for 63% BF. BSA did not use rubber mounting I know of so nothing to do with felt vibration pilot or frame just the engine internals. If someone stumbles across this BSA factory report post it please. I think I left in in the Crankshaft porno thread but ain't found it yet.

Xpongebob · Mar 22, 2015

Just read your story , Ken, how is this engine doing by now ?

lcrken · Mar 22, 2015

Xpongebob said:
Just read your story , Ken, how is this engine doing by now ?

It's put away in boxes right now, waiting for me to get back to it. I'm no longer fielding a bike in vintage racing, and I've been sidetracked by preparing 883 and 1007 engines for the two street Commandos I'm building. I do plan to get back to the short stroke, and build it as a 750 for landspeed racing, but not till after this year's INOA rally in July.

Ken

comnoz · Mar 22, 2015

hobot said:
I once found & posted here somewhere the BSA race research on 360 vertical twins dry BF of 52% giving the lowest force spikes when oil filled for 63% BF. BSA did not use rubber mounting I know of so nothing to do with felt vibration pilot or frame just the engine internals. If someone stumbles across this BSA factory report post it please. I think I left in in the Crankshaft porno thread but ain't found it yet.

You got that backward.

If you balance it at 63% without adding oil to the equation - when you fill it with oil the balance factor will be closer to 52%.

I have never understood why anyone would quote a "dry balance factor" Jim

Xpongebob · Mar 22, 2015

lcrken said:
It's put away in boxes right now, waiting for me to get back to it. I'm no longer fielding a bike in vintage racing, and I've been sidetracked by preparing 883 and 1007 engines for the two street Commandos I'm building. I do plan to get back to the short stroke, and build it as a 750 for landspeed racing, but not till after this year's INOA rally in July.

Ken

As Always... too many things to do

watson rider · Mar 25, 2015

do these have the oil bleed hole ala standard rod?[can only see one side of rod]

madass140 · Mar 25, 2015

No, no aftermarket rods have these holes, why? they are not needed.

Rohan · Mar 25, 2015

comnoz said:
I have never understood why anyone would quote a "dry balance factor" Jim

Can anyone quote, off the top of their head, what the measured volume/weight of oil in the galleries and sludge trap actually is ?
And how much of that volume is centrally located, so doesn't contribute/add/subtract from the balance factor weight.

I thought not.
Maybe thats why BF are oft quoted dry ?

comnoz · Mar 25, 2015

Rohan said:
comnoz said:

I have never understood why anyone would quote a "dry balance factor" Jim

Click to expand...

Can anyone quote, off the top of their head, what the measured volume/weight of oil in the galleries and sludge trap actually is ?
And how much of that volume is centrally located, so doesn't contribute/add/subtract from the balance factor weight.

I thought not.
Maybe thats why BF are oft quoted dry ?

The average is 100 grams give or take about 5 grams measured in the main cavity - not including the feed passage.

I balanced a crank on Monday that had been balanced by a shop in the northwest states. I was shocked by the work they had charged good money for. It wasn't even close and the flywheel was so butchered up I ended up replacing it. Jim

Tintin · Mar 26, 2015

comnoz said:
I have never understood why anyone would quote a "dry balance factor" Jim

Well, it makes sense to me as this would mean balancing the dry crankshaft to the dry values so that under operation the "wet" value is correct. In the end it is just a mathematical issue which influences the master weight and there's more ways to get that calculation wrong.

Tim

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