I am replacing the oil return tubes on a cylinder head. I have successfully removed the old ones as per the manual and have purchased two new ones. However, the manual states the new ones should be pushed and twisted into place but both are drop fits. I have measured the new oil return tubes along with an original fitted to another head with a micrometer and the new ones are about 0.1mm smaller in diameter. Is this normal or do the ends of the new return tubes need to be flared?

Alan
  • Re: 912 Oil Return Tubes

    by » 6 months ago


    Don't know if this will help ..but at least you'll know someone is thinking about it ;) Is the old original tubes flared a little?? Will it flare when you tighten it???
    I find that even a dumb idea sometimes leads me to something else that might help......

    Thank you said by: Alan. Hunter

  • Re: 912 Oil Return Tubes

    by » 6 months ago


    How about heating the new ones up a bit and hope for expansion?
    0.1 mm isn‘t a lot, is it?

    Thank you said by: Alan. Hunter

  • Re: 912 Oil Return Tubes

    by » 6 months ago


    The Big End has an O-Ring seal.
    The Small End is a close fit sealed with Loctite.

    The end probable Expanded/Crushed slightly when the heads were tightened.
    0.1 mm is about the thickness of a sheet of common printer paper. It isn't much.
    The Locktite on that end will fill the 0.1mm gap without a problem.
    I suspect the "Push and Twist" instruction is half to make sure it goes in all the way, and Half to spread out the Locktite evenly.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    whertzel1@yahoo.com
    Clicking the "Thank You" is appreciated by all.

    Thank you said by: Alan. Hunter

  • Re: 912 Oil Return Tubes

    by » 6 months ago


    What Bill said. :)

    p.s.
    Don’t be shy with the Loctite and make sure it coats the tube all the way around on that end.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-574-1080 Home (TRY HOME FIRST)
    520-349-7056 Cell

    Thank you said by: Alan. Hunter

  • Re: 912 Oil Return Tubes

    by » 6 months ago


    I will do as suggested and let you know results. Alan

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