Sump Strainers

Discussion in 'Thumpers' started by Stretch67, Dec 20, 2012.

  1. Stretch67

    Stretch67 Mad Scientist

    Joined:
    Mar 22, 2006
    Oddometer:
    8,548
    Location:
    Bent, But Not Broken
    XR400 Sump Strainer


    So... I picked up a '98 XR400 a couple weeks ago. It started on the first kick, ran smoothly, no smoke. I could tell she liked me,
    and she followed me home.

    Cool.

    Oil & filter change went smoothly, as did a cleaning of the frame downtube strainer... a very few small bits, but nothing major for
    a 15-year-old bike. I didn't check the sump strainer quite yet, as I didn't have the right-hand side-cover gasket, and didn't have any other
    reason to go in there.

    Further mechanical meanderings revealed an overly-stretched (don't blaspheme) cam chain. The tensioner spring is good,
    but has no more travel. Okay, that's two reasons to go into the right side of the case... cam chain and check the oil strainer.








    Hol-ee shiiiit!

    [​IMG]
    The ruler wasn't in there, really.

    This pile of scrap isn't from my piston. The bike starts and runs with no smoke, and there wasn't a speck of debris anywhere
    else in the entire sump... just in the strainer cavity.


    [​IMG]
    XR400 Sump Strainer. Remove the bolt (10mm head) and slide the strainer out. Not my photo.

    There is a line of black RTV between the cylinder and case, indicating a reassembly somewhere along the line. I believe after a
    previous piston was nuked, a mechanic didn't know about the existence of a sump strainer in Honda thumpers and let it pass
    unnoticed.

    I was familiar after having done some kick-starter work on my beloved old XL250 years ago.

    I removed my oil pump and back-flushed the pick-up tunnel, then flushed out the debris with kerosene in a large syringe. Medical
    types will recognize this procedure as 'lavage'. I lavaged the hell out of it. My sump is now clean enough to eat off of...
    if you don't mind kerosene residue.


    So... a kind note to mechanics out there: Please look for, check, and clean sump strainers, especially after major engine work.
    #1
  2. StevenD

    StevenD Hmmmm, dirt!

    Joined:
    Aug 3, 2005
    Oddometer:
    1,267
    Location:
    Holland, Amserdammed
    Are you sure its all old piston bits? Nothing magnetic?
    #2
  3. RideFreak

    RideFreak Torque Junkie

    Joined:
    Apr 17, 2009
    Oddometer:
    8,032
    Location:
    Out in the NM Dez somewhere
    Nice move cleaning that crap out of the motor. :clap

    When I purchase something used that has a motor, I naturally assume the worst, esp if it's been apart. I probably wouldn't have purchased it seeing that it's been apart and the mechanic (sic) used RTV to seal up the cases AND decided to leave a worn CC in there. Your picture is further proof of concept. Any mechanic worth his salt will flush out the motor in the event of a componet failure such as that. I'd say you're very lucky that the motor ran and still runs as well as it does.

    Lots of hacks out there.
    #3
  4. clapped_r6

    clapped_r6 The Spoad Warrior

    Joined:
    Jan 3, 2006
    Oddometer:
    3,115
    Location:
    Ridgefield, WA
    nice find.

    at the risk of starting another ktm bashing thread, i kinda like how my new-to-me rfs 450 has 2 strainers that are very easy to get to.
    #4
  5. Shooter1

    Shooter1 Been here awhile

    Joined:
    May 10, 2004
    Oddometer:
    484
    That picture scared ths shit outta me and I ain't scare of nuthin'! :lol3

    Good luck with the new bike.
    #5
  6. kubiak

    kubiak Long timer

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    Nov 25, 2007
    Oddometer:
    4,837
    Location:
    madera california
    dang!
    #6
  7. JensEskildsen

    JensEskildsen Long timer

    Joined:
    Mar 24, 2009
    Oddometer:
    1,259
    Location:
    Denmark
    Daymn... Mine has always showed up spotless, thank god. I would have shit myself if all that stuff came out of my bike :cry
    #7
  8. michael1968

    michael1968 Long timer

    Joined:
    May 20, 2009
    Oddometer:
    1,008
    Location:
    Newcastle, Australia
    Haha, win.

    Good luck with the bike.
    #8
  9. Shooter1

    Shooter1 Been here awhile

    Joined:
    May 10, 2004
    Oddometer:
    484
    What is the big chunk in the top LH corner. For Gods sake that's gotta be something serious doesn't it??? :huh. I changed my oil on my KTM 620 once a number of years ago and found one small pc of what looked to be the end of a cotter pin on the drain plug magnet, about the size of the tip of a lead pencil. I was nervous as a whore in church about that but the consensus was just to go ahead and ride it, so I have and it still runs OK and doesn't make any funny noises, (knock on wood). Hopefully you have the same luck.
    #9
  10. Stretch67

    Stretch67 Mad Scientist

    Joined:
    Mar 22, 2006
    Oddometer:
    8,548
    Location:
    Bent, But Not Broken
    It's a piece of piston skirt a bit bigger than a man's thumbnail. You can also easily recognize the piece of piston ring down near the ruler. Some of the pieces are unrecognizable chunks of slag, I presume from the top of the piston as it melted down. Other pieces are fractured from the piston, and others are bits of steel from the rings.

    Honestly, I'm not worried about the engine as it sits now, as it ran perfectly even before I tore into the strainer here. I just wanted folks out there to know and be on the lookout for sump strainers. Like RideFreak said earlier, "lots of hacks out there".
    #10