Stuck Piston - help

Discussion in 'Airheads' started by matteo, Mar 25, 2012.

  1. matteo

    matteo HPM

    Joined:
    Apr 30, 2005
    Oddometer:
    510
    Location:
    San Jose, CA
    I have a R51/3 engine that I am tearing apart. The engine is the same as the /2 engines. One of the pistons is stuck in the cylinder. The engine does not turn over. I got one of the cylinders off, but the other has the piston completely stuck.

    I can unbolt the cylinder from the case and turn the crank, but again the piston will not move within the cylinder.

    I tried soaking it with some penetrating oil for a couple of hours. I also applied heat to the cylinder (got it to the point it was too hot to touch), but absolutely no luck. I tapped the cylinder lightly with a mallet to see if I can get it to break loose, but it did not work.

    Any suggestions?
    #1
  2. Hedge36

    Hedge36 My e-penis is huge.

    Joined:
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    47,579
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    I know a guy who freed one like that by bolting the head on, pouring a half cup of penetrating oil down the plug hole, then chucking an air line to the plug hole and letting it sit with about 25 psi on it. The next morning he heard a muted "pffft" as the loosened piston made its way down the bore.

    There may be better ways, but it was effective and safe.
    #2
  3. elite-less

    elite-less Been here awhile

    Joined:
    Dec 21, 2009
    Oddometer:
    558
    Location:
    The Puget Sound Convergence Zone
    I used this simple tool to remove the stuck piston on my r75. I tapped the metal bar for a threaded rod and bolted it to the head. Double nutted the threaded rod and wrenched away. Popped the piston free in a few moments.

    Not sure how the head is on a /3... but you might glean an idea from this.

    <img src="http://farm6.staticflickr.com/5092/5440487978_c7f6cf38c8_z.jpg" width="480" height="640" alt="IMG_3854">
    #3
  4. knary

    knary sunshine and puppies

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    portland, or
    That cylinder is the prettiest shade of rust.
    #4
  5. fishkens

    fishkens Long timer

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    :lol3

    I hear it never sleeps.
    #5
  6. mykill

    mykill odd

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    Los Angeles
    My buddy has used Coca cola successfully in stuck Hondas. You need to be more patient than a couple hours. I like the sound of the penetrating oil and compressed air trick.
    #6
  7. matteo

    matteo HPM

    Joined:
    Apr 30, 2005
    Oddometer:
    510
    Location:
    San Jose, CA
    Thanks. I'll try a similar setup.
    #7
  8. knary

    knary sunshine and puppies

    Joined:
    Jun 27, 2002
    Oddometer:
    29,630
    Location:
    portland, or
    Like my hunger for doughnuts. :lol3
    #8