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Thread: Cylinder Bore Surface Finish

  1. #1
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    Cylinder Bore Surface Finish

    Hello. I have a question about honing the cylinder bore on 2009 Buell XB12Scg with 20000 miles.

    Manual says when you reassemble the cylinder and piston with new rings you need to hone the cylinder bore to achieve 60 deg crosshatch pattern. But original crosshatch pattern angle on my cylinder looks much smaller, maybe about 30 deg, not even 45 deg like the most common angle for hone patterns.

    Is it manual mistake? Should I hone with the same angle or hone with 60 deg over the original crosshatch pattern?

    Here is a picture of my cylinder with original crosshatch pattern.

    Last edited by TPEHAK; 11-25-2017 at 04:52 AM.

  2. #2
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    Manual says when you reassemble the cylinder and piston with new rings you need to hone the cylinder bore to achieve 60 deg crosshatch pattern.

    THAT recommendation assumes you're using a dealer supplied OEM ring kit. the cross-hatch finish and specific angles totally dictated by the manufacturer of the rings used during motor rebuild.
    if you're asking questions like this now and doing the rebuild yourself i truly feel sorry for that poor motor.

  3. #3
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    But why in this case the original pattern is less than 60 deg? Did they assemble motorcycle with different rings? Is it OK to hone the cylinder to different angle than it was originally? After this there will be two patterns with two different angles.
    Last edited by TPEHAK; 11-25-2017 at 03:28 PM.

  4. #4
    Senior Member Silverrider's Avatar
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    What does the top of the piston look like??

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    Senior Member Cooter's Avatar
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    The purpose of the crosshatch isn't diminished by the narrow angle deviation. Crosshatch to 60*. Just like the manual states.

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    Quote Originally Posted by Silverrider View Post
    What does the top of the piston look like??
    The top of the pistons had around 1 mm thick hard deposits. The piston rings grooves was very clean, no any deposits in the rings grooves at all.




    I soaked them in Aircraft Remover to clean the piston top.



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    I've seen a lot of pistons in my time, I've never seen that much carbon on any of them, in fact, that's more carbon than I've seen on all of the pistons I've seen put together ! Why would that be, I mean what would cause that ?

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    Quote Originally Posted by njloco View Post
    I've seen a lot of pistons in my time, I've never seen that much carbon on any of them, in fact, that's more carbon than I've seen on all of the pistons I've seen put together ! Why would that be, I mean what would cause that ?
    There are many reasons for carbon buildup, Most carbon buildup is from oil getting past the wiper rings on the piston. Rather common on a high mileage engine. Can also occur from an excessively rich mixture, but that is very rare on a modern fuel injected engine with electronic ignition and controls.

    Another source is a bad PCV valve that can suck excessive amounts of crankcase gases into the intake system.

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    I'm sure if you take a look in your Buell cylinder at 20000 miles you will see the same. Maybe this is how Buell build motorcycles, with bad seals, and there is nothing you can do about it. Here is first random picture from Google search


  10. #10
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    I'm sure if you take a look in your Buell cylinder at 20000 miles you will see the same. Maybe this is how Buell build motorcycles, with bad seals, and there is nothing you can do about it.

    bull****ometer.jpg



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