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Author Topic: Pitting On Pistons  (Read 2167 times)

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Offline campbmic

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Pitting On Pistons
« on: February 13, 2010, 04:01:43 PM »
I'm rebuilding a 1975 CB550 and my pistons looked very good and looked as if they had no pitting at all and just a little carbon build up. I cleaned them off today and found some pitting under the carbon. Does this mean the pistons are toast? Can I sand the piston to get rid of the pitting since it isn't very deep at all? Does this even matter or can I just reinstall the piston?

Thanks for any help! Only two of the pistons had pitting on them and they didn't have very much carbon on them at all which I would assume means the bike had low miles (no odometer)



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Offline bwaller

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Re: Pitting On Pistons
« Reply #1 on: February 13, 2010, 04:06:15 PM »
That bit of pitting won't have any effect. Be concerned about the other tolerances though.
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Offline campbmic

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Re: Pitting On Pistons
« Reply #2 on: February 13, 2010, 04:08:24 PM »
Thanks bart! Also does anyone have any tips on how to remove old rings without breaking them? Ive seen some threads but can't remeber exactly where they were
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Offline lone*X

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Re: Pitting On Pistons
« Reply #3 on: February 13, 2010, 04:23:02 PM »
Use a piston ring expander.  Holds the ring ends at the gap and seperates them while keeping the ends in the same plane.  The makes removing and replacing them much easier and a lot less prone to breaking.  

Example:
http://www.bosstoolsupply.com/index.asp?PageAction=VIEWPROD&ProdID=11833
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Lone*X  ( Don )

75 CB550K1  
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Offline BLUE71TURBO

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Re: Pitting On Pistons
« Reply #4 on: February 13, 2010, 06:29:56 PM »
Trash the old rings !  Install new ones and hone the cylinders.  You'll be glad you did.   ;D
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Offline MRieck

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Re: Pitting On Pistons
« Reply #5 on: February 13, 2010, 07:44:14 PM »
Quote from: BLUE71TURBO on February 13, 2010, 06:29:56 PM
Trash the old rings !  Install new ones and hone the cylinders.  You'll be glad you did.   ;D
I agree
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Offline dave500

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Re: Pitting On Pistons
« Reply #6 on: February 14, 2010, 02:06:05 AM »
make sure you get all and any carbon out of the ring grooves,an old broken ring fits the slot and can be used as a scraper, dont gouge the metal.
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