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Thread: Cylinder Bore Surface Finish

  1. #31
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    AZ is absolutely right about this guy, to just not pay any significance to helpful things people post up about you especially negative statements is very troubling but, I will not waste anymore time on you or your posts even though, I found some of them to be interesting.

    Good luck in your endeavors.

  2. #32
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    AZ, Thanks for the info.

  3. #33
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    Good news! I have inspected the cylinders, and they are good as I expected!

    Here is metrology setup







    Here are measurements results. I measured twice with digital gauge and with dial gauge. On the dial gauge (red color results) I can read between 0.0005" increments with 0.0001", and the dial gauge results correlate with digital gauge results, so pay attention to the red color results. Digital gauge shows rounded results with 0.0005" increments so those results may be confusing.




    Here are calculated deviations




    Here are specifications from service manual for reference





    So as you can see there is only one place (front cylinder bottom area) where out of roundness is just 0.0001" above allowed limit, nothing criminal.


    I also inspected the cylinders flanges flatness, they are perfectly flat, there is no any spot in all direction on top and bottom where I can slide thinnest (0.002") feeler gauge. So both cylinders are not warped at all.







    Here are flatness allowances for reference




    So those cylinders are good to go next round!
    Last edited by TPEHAK; 11-27-2017 at 07:03 AM.

  4. #34
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    Alright, the cylinders have been deglazed to 60 deg crosshatch pattern as manual suggests. Here is my setup.


    I cut 60 deg gauge from transparent film




    Here is difference between original hone angle and the angle manual suggests. As you can see the original crosshatch pattern is significantly sharper





    I cut support plate for the cylinder from plywood





    Glued some wood blocks to support the cylinder from rotation





    And here is how I honed. First of all I measured the Dewalt drill turning speed with slomo camera om my smartphone. I found this drill performs 7 revolution per second at 1st gear at full throttle. I measured hone stroke and created quick 3D CAD model to estimate how much turns per stroke I need to achieve 60 deg hone angle





    I found I need about 1 turn per hone stroke in one direction to get 60 deg pattern, but at 7 revolutions per second I need to move the hone back and forth about 3 times per second which is quite fast and hard to control. So I adjusted speed of the drill to about 2 turns per second and actuated hone with 1 back and forth move per one second. So now I have 1 turn per one stroke and 60 deg crosshatch pattern. Here is my setup





    The new hone lines intersect each other perfectly at 60 deg




    Washed my cylinders with hot water and dishwasher, oiled bore surfaces and wiped off all contaminations





    Now I'm ready to install new rings. Here are freshly honed surfaces

    Last edited by TPEHAK; 11-27-2017 at 07:41 AM.

  5. #35
    Senior Member AZmidget91's Avatar
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    Quote Originally Posted by TPEHAK View Post
    If out or roundness of cylinder bore is within specification it should be sealed good enough with new rings.

    I see one issue in you cylinder cleaning method. It looks like you used scotch bright pads to remove the old gaskets and old gaskets marks from cylinder surface. The issue is you have to wash cylinder thoroughly after this because of those pads have abrasive material which is harder than steel. You did not disassemble this, so you was not able to clean parts good enough. Remained abrasive material from the pads will cause excessive wear of the engine and will damage cylinder and piston components. The engine processed such way will never run right again.
    Cylinders were washed thoroughly to remove any abrasives used and carbon...

  6. #36
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    Quote Originally Posted by AZmidget91 View Post
    Cylinders were washed thoroughly to remove any abrasives used and carbon...
    The issue is you can not reach all the places when piston is in cylinder. Some abrasive material stick between cylinder and piston.

    If I would do such way, I would pour some Aircraft Remover in cylinder bore to dissolve the carbon and remove it by non mechanical way, then washed it with detergent and blow the carbon out with air compressor. Then masked the cylinder bore and piston with tape or foam and only after this cleaned the gasket surface with scotchbright and wiped everything off before removing the mask so no abrasive material will fall in between cylinder bore and piston.
    Last edited by TPEHAK; 11-27-2017 at 07:57 AM.

  7. #37
    Senior Member AZmidget91's Avatar
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    Quote Originally Posted by GregoXB View Post
    AZmidget..... I want to play devil's advocate.... Out of curiosity, how did your pistons get all that carbon crud on there??
    This was as soon as I bought the bike. Was babied by the previous owner, no breather reroute, possibly used cheap gas...

  8. #38
    Senior Member AZmidget91's Avatar
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    Quote Originally Posted by TPEHAK View Post
    The issue is you can not reach all the places when piston is in cylinder. Some abrasive material stick between cylinder and piston.
    Not enough to worry about. Not everything has to be perfect in this world....

  9. #39
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    The Allied forces could have used some of that Aircraft Remover to help us defeat the Luftwaffe in WWII.




    I heard they use that same Aircraft Remover in the Bermuda Triangle though. Dangerous stuff!! Use carefully or you'll never find your aircraft again!






  10. #40
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    Today I inspected the old rings gaps.




    Here are results.





    Here are new components allowances from service manual. As you can see the second compression ring gap is out of new component limit on both cylinders. It looks pretty obvious because of 2nd compression ring is the thickest and the most rigid ring and has the most friction



    Last edited by TPEHAK; 11-29-2017 at 06:50 AM.

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