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Thread: Rear cylinder leak

  1. #1

    Rear cylinder leak

    Hi all,

    While resetting TPS and renewing engine and primary oil I noticed a oil leak at my rear cylinder.
    Below a small video which I have made during draining of engine oil (in the rear fork) so not while the engine was running.
    The enging was at approximatly 100°C as I just had reset my TPS and had to warm the bike up for fine setting my Idle RPM.
    https://youtu.be/jSAP5GRVfKE
    The bubbles that you see does worries me, is causes by:
    - it gasket faillure?
    - loose bolts?
    - small crack in cylinder?


    I'have the manual from Buell (year 2005) and determined that I need to do the following:
    There are two options:
    1- perform a ENGINE ROTATION for service (3.3) at cylinderhead (3.6)
    --> To check if some bolts are loose
    2- perform a STRIPPING MOTORCYCLE for SERVICE (3.4) of the engine itself
    --> To remove the cylinder and replace the gasket


    My question is, I am a clever guy, I worked on framework of motorcycles but never on engines.
    - Is it possible to do option 1 (from above) if you do not have engine service experience?
    - but which bolts do I need to check causing leakage at cylinder?
    - Is it bad to wait until the winter to bring the bike to dealer for maintenance as I do not have tools to do option 2 (from above)?
    - Or are their other options to do before I do above?


    I will drive a few kilometers to check if the engine have leak problems after driving but I assume it has.
    Below some pictures after cleaning the area where bubbles appear (see movie above) while draining oil.
    Small irregularity at rearcylinder.jpg
    13223433_10156878891810111_766560027_o.jpg
    Can this be a cause for the leakage?

  2. #2
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    Its either a leaking base basket, or rocker box gasket leaking to the bottom and bubbling. Either way you need to rotate the engine to get to those bolts. Its not a hard job to do if you are handy with a wrench at all. Just get yourself the james gasket (JGI-17049-04-X) set and freshen the gaskets up. And if its that bad I would not wait till winter!

    There are 4 large chrome cap bolts 2 are in the open and 2 are under the rocker box so you gotta remove the rocker box to get to those anyway.

    Heres a how-to thread on engine rotation
    http://www.buellxb.com/forum/showthr...gine-With-Pics!
    Last edited by Cosworth; 05-12-2016 at 11:23 AM.

  3. #3
    Senior Member Cooter's Avatar
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    Damn good info ^^^^^

  4. #4
    Quote Originally Posted by Cosworth View Post
    Its either a leaking base basket, or rocker box gasket leaking to the bottom and bubbling. Either way you need to rotate the engine to get to those bolts. Its not a hard job to do if you are handy with a wrench at all. Just get yourself the james gasket (JGI-17049-04-X) set and freshen the gaskets up. And if its that bad I would not wait till winter!

    There are 4 large chrome cap bolts 2 are in the open and 2 are under the rocker box so you gotta remove the rocker box to get to those anyway.

    Heres a how-to thread on engine rotation
    http://www.buellxb.com/forum/showthr...gine-With-Pics!
    Thanks for the link Cosworth, it's like Cooter is saying, awesome good info to start with rotating the engine.
    Small question for you Cosworth, to change the "James Gasket" for the base and the rocker box it's sufficient to rotate only your engine?
    I do not need to strip the motorcycle from the engine to change those gaskets?
    Because at first impression after reading the manual I though I needed to strip for removing cylinder or am I wrong?

  5. #5
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    No need to completely remove the engine it stays on the bike its just rotated around where you can get to the rear cylinder through the frame (basically where the front currently is)
    That gasket set comes with everything you'll need to do the top end of the bike.

  6. #6
    Quote Originally Posted by Cosworth View Post
    No need to completely remove the engine it stays on the bike its just rotated around where you can get to the rear cylinder through the frame (basically where the front currently is)
    That gasket set comes with everything you'll need to do the top end of the bike.
    My HD dealer did not have James Gaskets so I received a set of Original gaskets but not the complete set of all gaskets for the engines.
    just the ones that I needed to change after disassembling my both cylinders.
    At this state my cylinders are disassembled but I can not seems to place a few gaskets which I received, being the following:

    Gasket unknown 1.jpgGasket unknown 2.jpg

    Can you help me and explain what they are for?

    The ones that I know and I defently need to replace are the following and I think that this is sufficient for the assembly that I did:
    engine status 1.jpgGasket known.jpg

  7. #7
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    Did you remove the pistons from the cylinders? If so that may create a long term problem with oil consumption, loss of power, poor starting due to the rings no longer being seated. If so, new rings and a professional honing of the cylinders, after reassembly heat cycled to seat the rings and a few hundred easy miles to wear them in

  8. #8
    Quote Originally Posted by Theycallmecrash View Post
    Did you remove the pistons from the cylinders? If so that may create a long term problem with oil consumption, loss of power, poor starting due to the rings no longer being seated. If so, new rings and a professional honing of the cylinders, after reassembly heat cycled to seat the rings and a few hundred easy miles to wear them in
    I removed the Rocket box, Cylinder head and Cylinder of my engine base.
    So if that is what you mean than yes I did above.
    apart of cleaning my pistons a little bit I did not touch them an further.

    ==> So if I understand you correct, I need to perform the honing?
    Is that something that you need to for each engine, the honing process, if you remove the cylinder of the pistons?
    Because that's the first time that I am hearing this.

  9. #9
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    People remove the pistons from the cylinders and reinstall with no noticable problems, at least that they are aware of. I have done mutiple top end rebuilds where rungs didnt seat properly. Better safe than sorry while its apart, hone the cylinders and get new piston rings



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