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Patches on cylinder walls

Discussion in 'XJ Technical Chat' started by Rasput, Apr 1, 2020.

  1. Rasput

    Rasput Member

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    When I first got the 83 xj900 the engine was siezed. I carefully got it freed up but when I took apart the engine I found this on the cylinder walls. The patches are smooth to the touch but still concern me. Would I be able to dingle hone the cylinders to get rid of them or should i have a machine shop bore the 20200401_184955.jpg 20200401_184950.jpg 20200401_184955.jpg 20200401_184955.jpg 20200401_184950.jpg cylinder? I'm trying to keep the repair as simple as possible. Prefferebly just needing new piston rings. Let me know what you think.
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    Hone then then measure them to see if they are in spec for rings.
     
  3. Rasput

    Rasput Member

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    If I hone them do I need new rings since they have a new crosshatch?
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    if you think your rings are undamaged and good you can reuse them. but why risk it and have to do it over

    what was siezed?

    partzilla

    PISTON RING SET (STD)
    15A-11603-00-00

    $45.99
    $32.11
     
    Last edited: Apr 1, 2020
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  5. Rasput

    Rasput Member

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    It was one of the pistons in the cylinders. I also have a compression ring stuck on the number 3 piston. So I should probably replace the rings anyway. Is it pretty easy to dingle hone or should I have a machine shop do it?
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    when you hone it you will need to measure the cylinder walls to make sure the diameter is in spec you want to do this before even buying the rings.

    price it out at a shop

    specs are in manual do you have one?
     
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  7. XJ550H

    XJ550H Well-Known Member Premium Member

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    specs cyl measure.PNG cylspec.PNG
     
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  8. JBurch

    JBurch Active Member

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    You are now in the Twlight zone; between doing a low buck resurrection or a full blown rebuild. Questions are what are your expectations of the bike when you are done; ride and enjoy or fix and flip. IF, IF, there are no scratches on the cylinder walls, you could just hone, do rings and go, that would be the low buck route. If there are scratches, bore it over size. The patches you see; I call that shadowing, is where the pistons were getting real close and personal to the cylinder wall due to moisture and galvanic action between aluminum and iron; I don't think they will hone out with out taking the cylinder out of spec. A "blue berry hone" is not for stock removal, just cylinder wall conditioning, 30 seconds is all that is needed.
     
  9. Rasput

    Rasput Member

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    I am ordering a physical manual soon but I have a pdf one. Compression was good across the board even with a stuck compression ring. Roughly 120-130 with the lowest one being the cylinder with a stuck compression ring. Keep in mind that the bike sat outdoors for 3 years. I'll try to get better pictures of the spots tomorrow and post them.
     
  10. Jetfixer

    Jetfixer Well-Known Member

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    When you hone the cylinder use LOTS of WD40 , I'm sure you already know this but some in the studio audience don't , this saves the hone stones from excessive wear and the same on the cylinder. From the looks that is pretty deep , I would try the hone and see , and by all means replace the rings.
     
  11. a100man

    a100man Well-Known Member

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    I had similar on my Radian motor.. it's water ingress damage - condensation or even rain if the motor was stood without carbs on it. I bought 2-3 more scrap motors for less than 50 quid each trying to find better bores and in the end settled on one which had minimal corrosion on one bore - I posted pics at the time maybe you can even find the thread. I'm cheap so I 'honed' the bores by hand with 300 grit paper I think. Got some new rings (bargain at 100 USD) and buttoned it back up. Compression was slightly down on the 'bad' cylinder but the motor is generally OK. On it's maiden year after the 'rebuild' I went to Isl e of man and put 500 mile on it without any real issues. As JBurch suggests - it depends on your expectations. Hone and rings and it will almost certainly run Ok for most people. As my brother often says of my budget projects ' It's not a race motor is it?'

    BTW Rebore, pistons and rings will cost you at least 500 USD probably more - and that's if you can find the oversized parts. Cars are MUCH cheaper for this kind of thing.
     
  12. Rasput

    Rasput Member

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    Does anybody know if any of the other XJ use the same cylinders?
     
  13. XJ550H

    XJ550H Well-Known Member Premium Member

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    You have a 900 there it's the only bike with those cylinders
     
  14. a100man

    a100man Well-Known Member

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    A guy in Ukraine made Seca-II (Diversion) 600 barrels fit the older model, maybe Seca2 900 barrels will fit yours? He did make some slight mods IIRC. See Gaz 8-ball cafe thread,
     
  15. a100man

    a100man Well-Known Member

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  16. a100man

    a100man Well-Known Member

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    ..don't mention it.
     
  17. Rasput

    Rasput Member

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    That is an awesome build. I brought them to a good machine shop I know. They said it mainly looks like stains and nothing too deep. We are going to try to hone it a little bit and get new rings after checking the specs. Thank you for sharing that link. Anybody know if xjforever's oversized piston rings require over sized pistons.
     
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  18. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Yes, they do!
     
  19. Rasput

    Rasput Member

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    You wouldn't by chance know where to obtain oversized pistons for the xj900rk? I'm just trying to plan out worst case scenario.
     
  20. XJ550H

    XJ550H Well-Known Member Premium Member

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    if you cant get oversized pistons you may be able to resleve the cylinders
     

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