Buell engine rebuild advice, or

Discussion in 'The Garage' started by B.Curvin, Nov 24, 2010.

  1. B.Curvin

    B.Curvin Feral Chia tamer

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    always look on the bright side of life?

    Maybe it's a good thing the previous owner was ham fisted. I started changing out

    the exhaust studs etc as recommended in my other Buell thread. The PO had insisted

    on repairing an exhaust leak before we traded bikes. I said leave it alone but

    he did it anyway. I found the front cylinder exhaust studs were finger tight.

    The rear cylinder only had a nut on one stud and the stud without a nut was

    cross threaded. I pulled the head off to get better access to the stud and found this.


    Scratches can be felt with a fingernail in the band the red arrow points to.

    [​IMG]

    The piston

    [​IMG]

    The different colors are not a reflection.

    [​IMG]

    So, do I need to strip it all the way down and hone the cylinders and install new pistons?
    #1
  2. GB

    GB . Administrator

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    Nothing here, let's move this to The Garage.
    #2
  3. Tosh Togo

    Tosh Togo Long timer

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    By the look of those scratches, it more likely will be next oversize. Honing enough to make them go away will probably have the original pistons trying to go sideways with all the extra elbow room. Take both jugs to a machine shop (NOT the dealer!) and see how much they think will need to be taken off to start over.

    Pics help, but a machinist with the part in hand is better.

    Let's say you your friendly neighborhood machinist miraculously makes things like new again with only .003" material removal.

    That's not three thou bigger, it's that much gone from each side of the cylinder. :eek1

    With that much unhappiness upstairs, you should also have a good look at the bottom end while you're that far into it.

    If that shows more problems, a better/cheaper answer would be to find another complete engine.

    Or button it back up and sell it.:lol3
    #3
  4. B.Curvin

    B.Curvin Feral Chia tamer

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    No worries there. I never taken anything to a dealer.

    I've got a local cylinder/head guy that is top notch. Reeves in Asheville.

    I figured I'd be going up a size. I'll get Reeves input then grab a set of Wisecos. :clap
    #4
  5. Anorak

    Anorak Woolf Barnato

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  6. bomber60015

    bomber60015 Anatomically Correct

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    fear not -- Tuber motors were ridden in ways Milwaukee never dreamed of, and you can see wear like that in the cylinders all day long without having any appreciable wear in the lower end of the mill.

    1250 kits are reasonable, and you get new pistons and cylinders . . . . . no more work to put together than reassemebling what you've got.

    but, yeah your cylinders/pistons need attention -- maybe valve guides/seal, as well.
    #6
  7. Bobthebiker

    Bobthebiker not normal

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    did the PO run it with low oil or someting? or no air filter? those are some NASTY scoring marks in that cylinder, with what looks like oil buildup on the piston.

    personally, I'd go for new jugs and pistons, along with redoing the heads.
    #7
  8. fatboy

    fatboy Been here awhile

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    Seriously? The answer is that you measure it and make decisions based on the data. If you are not sure how then take it to a machine shop and ask them to do it. Work with the facts.
    #8
  9. B.Curvin

    B.Curvin Feral Chia tamer

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    Thanks :wink:
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  10. RJW

    RJW Adventurer

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    #10
  11. ian03xl

    ian03xl Been here awhile

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    This company is an excelent source for sportster and buell engines. I've used their 1250 kit amazing products and customer service is top notch. Talk to Dan he can set you up with a rebore or anything you may want to do.
    #11
  12. B.Curvin

    B.Curvin Feral Chia tamer

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    Thanks for the tips. I had already spoken with NRHS earlier today. I was

    quiet disappointed when I found out their cylinders are cast in china. I'm going to

    go with Wiseco pistons and have my local guy rebore my stock cylinders

    and possibly redo the heads.
    #12
  13. RJW

    RJW Adventurer

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    make sure they use torque plates when boring cylinders, otherwise they'll be out of round when installed and heads torqued down
    #13
  14. B.Curvin

    B.Curvin Feral Chia tamer

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    :clap

    Thank you thank you for that. I've read that torque plates must be used with Harley

    cylinders in American Iron and such but had not thought about it since I rarely

    (never before actually) work on Harleys. I'm sure Reeves knows this and has them, or would

    send me to someone that does but it's nice to have the info so I know to ask.
    #14
  15. concours

    concours WFO for 41 years

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    This. Hard to judge the scoring from the image, the cross hatch honing pattern is still visible all the way up to and between the scoring. I'd offer an overheating event (like stuck in traffic) was the culprit. It wasn't normal wear, as witnessed by the cross hatch still being visible.
    #15
  16. dentvet

    dentvet Long timer

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    it looks like the scratches are from the carbon on top of the piston kissing the cylinder. there is a halo of bare piston all the way around until you get to the area that is scratched. doesn't look that bad to me. have to measure if your worried its out of round.
    #16
  17. rouser

    rouser Buell Not Dead

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    revperf.com is a better source for 1250 kits. much better jugs, but a little bit more pricey. well worth it.
    #17
  18. B.Curvin

    B.Curvin Feral Chia tamer

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    I think sir that you have nailed it. :1drink

    But, I'm afraid I have to go a bit (a LOT) deeper than I had planned.

    It would seem that 90% of the fasteners on this bike are seized or cross threaded.

    I'm going to make it a long term winter project and take it completely apart

    and fix all the evils bestowed upon it by previous owners. Hell, I can't even get

    the swingarm isolator bolts out.

    The sad current state of affairs.
    [​IMG]
    #18
  19. Motomedic

    Motomedic Long timer

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    The older swingarm isolator bolts (the version using the 1/2 Allen wrench) are indeed a PITA to deal with, usually seizing in the bearing adjusting "bolt". Make sure you use the updated isolator kit with the new, button head Torx bolt. There's a updated front exhaust mount too, so make sure you use that when reassembling the bike.

    Also, the frame comes OFF of the engine/swingarm mount block/swingarm as a unit (with the front end complete) easier than the other way around. Use a jack/lift/swingarm stand to support the powertrain, remove the two pivot bolts and the one Isolator bolt through the front isolator and the frame will come off as a unit. leaving the powertrain behind.

    As for the powertrain, I tend to prefer the Nikasil lined cylinders for hi-perf applications, as I've had the liners come unbonded from the aluminum, causing head gaskets to fail. I've been running the Revolution cylinders for 90k+ miles (installed at about 18k on the bike-I forget exact mileage) and when I had it apart at 90k, the bores ware still perfect after many years of flogging it mercilessly.

    There are a few more updates/tweaks that'll make the bike much more enjoyable, so keep posting and I'll do my best to help along the way (BTW, I've been a certified Buell tech/owner for quite a while now-I'm pretty familiar with the Tubers having owned my S3T for 120K miles/10 years).
    #19
  20. B.Curvin

    B.Curvin Feral Chia tamer

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    Thanks for popping in. First question. Is the later aluminum Cyclone swingarm

    interchangeable with mine? I was thinking of replacing the whole swingarm

    mounting block and swingarm with one from ebay. I shall be bending you ear from time to time.

    Today I was going to lower the whole thing onto wodden blocks on the

    floor, lift the frame off and go from there. The factory loom is chopped

    all to heck so I'll be replacing that too. Fortunately parts are cheap and plentiful

    unlike the 98 Tiger I traded for it.
    #20