Replace con rods without splitting cases?

B

BrianK

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Jun 14, 2007

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1,820

• Saturday at 4:50 PM

• #1

Head is off but not cylinders, yet. Once the cylinder block is removed, is it possible without further disassembly to install new con rods?

 

possm

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Jul 3, 2009

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965

• Saturday at 4:52 PM

• #2

No.

 

B

bmepkid

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Sep 25, 2020

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• Saturday at 4:53 PM

• #3

No. There's no way to access the con rod nuts. You'll have to split the cases.

 

concours

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Dec 29, 2011

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• Saturday at 4:56 PM

• #4

BrianK said:

Head is off but not cylinders, yet. Once the cylinder block is removed, is it possible without further disassembly to install new con rods?

Click to expand...

Why do you want to replace the Conrod's?

 

Tornado

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Dec 5, 2017

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• Saturday at 4:56 PM

• #5

BrianK said:

Head is off but not cylinders, yet. Once the cylinder block is removed, is it possible without further disassembly to install new con rods?

Click to expand...

You could saw a big hole underside of cases to access the conrod big wnd nuts i guess...but that creates other issues...

 

B

BrianK

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Jun 14, 2007

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• Saturday at 5:01 PM

• #6

Thanks folks. No surprise, but I didn't want to assume.

To Concours' question: Pistons need replacing, and if it could be done without splitting the cases I'd spring for some of Jim Schmidt's shortened pistons/longer con rods. Not to be.

Appreciate the help. - B

 

B

bmepkid

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• Saturday at 5:16 PM

• #7

Pistons are one thing. Con rods are another.

 

NORTSTER1974

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• Saturday at 5:58 PM

• #8

Not unless it's a BMW boxer motor.

 

S

seattle##gs

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Oct 28, 2014

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• Saturday at 6:23 PM

• #9

You could use just his light weight pistons designed for stock rods. I think reducing piston weight would always be a good idea.

 

possm

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Jul 3, 2009

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965

• Saturday at 6:24 PM

• #10

IF you do not know the history of your motor it would be a bit silly to not split the cases and at least clean out the sludge trap, to me it is preventative maintenance.

 

SteveA

Joined

Dec 20, 2011

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3,476

• Yesterday at 5:04 AM

• #11

possm said:

IF you do not know the history of your motor it would be a bit silly to not split the cases and at least clean out the sludge trap, to me it is preventative maintenance.

Click to expand...

... And check the big ends.....

 

Schwany

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Apr 22, 2020

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• Yesterday at 9:42 AM

• #12

Adding JS light weight pistons to stock rods and not getting the crank rebalanced for the weight change might not be ideal. Have not done it that way myself, so mostly talking maybe. However, with a Commando the rotating mass being a touch off balance might not be as noticeable as it is on a pre-Commando Norton.

 

hhh

Joined

Jan 7, 2023

Messages

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• Yesterday at 11:51 AM

• #13

Per JS, for both 750 and 850: "because of the lighter pistons this means your motor will shake less vertically and the same horizontally – a win win situation. Rebalancing is not necessary." https://jsmotorsport.com/pistons-for-stock-rods/