'11 990Adv persistent slow oil leak

Discussion in 'Ridiculous streetbikes with 6 CPUs and too much HP' started by kcc, Mar 23, 2014.

  1. kcc

    kcc Been here awhile

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    Last summer I started noticing the skid plate always had some tar in it instead of just dirt. By the end of the summer it would occasionally micturate upon my rug, man, progressing to always leaves a spot...

    Full careful oil change in prep for spring, with the full KTM rebuild kit, removed o-rings and replaced them all along with screens, crush washers, the lot. Squeaky clean everywhere and I hung the plastics back on but left the skid plate off. Warmup, fill/top, ride. No oil, yay!

    Yeah it's back. Guess it just took a while to migrate enough to start to drip again plus new oil is so clean :-) Over the last month it's dripped enough to warrant keeping a pan under it at all times, so I started carefully peeling pieces off to see if I can spot the real source,

    I think it's coming from the oil tank sender line, that has the conical screen inside of it. That's such a simple connection, flat plastic on flat metal, I'm not sure why it would start to ooze and get worse. Torque is correct, I thought the mating surfaces were clean. Any ideas on how to stop it since there is not an o-ring or replaceable of any kind that I remember or see in this drawing?

    [​IMG]

    [​IMG]
    #1
  2. gearheadE30

    gearheadE30 Long timer

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    I'd go with RTV, since that isn't an interface that you'd remove often. The black stuff should work fine, just make sure there is no oil on the surfaces at all until after it dries, which takes about 24 hours.
    #2
  3. kcc

    kcc Been here awhile

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    Thanks gearhead!

    On a related topic... can someone explain what *is* that line? The check valve looks to open out of the reservoir/downward, and the rubber line turns into two hard metal lines that go into what i believe is the dry sump.

    Is this supposed to be a low pressure, suction-only line that pulls oil from the upper reservoir into the oil pump for distribution on the bottom end of the engine?

    I'm just wondering how much pressure that joint is ever intended to be exposed to, since it's flat plastic on flat metal, and why it doesn't have more of a gasket or o-ring interface if it's intended to be pressurized *at all*....
    #3
  4. Boatman

    Boatman Membership has it's privileges ;-)

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    There is an o-ring/gasket for that connection. It's #11 in the pic you posted. And in the line drawing on the left the dark black u shaped part at the bottom of #10.

    [​IMG]


    And #19 on the parts fiche.....

    [​IMG]


    It fits over the base of the screen.
    #4
  5. Boatman

    Boatman Membership has it's privileges ;-)

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    And yes it's the return line
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  6. kcc

    kcc Been here awhile

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    dang Boatman I got all excited. I think that is the green, not toroid washer (#19), right? That one is in there... I had *no* rubber/silicon parts left over from the KTM oil change kit.

    I wonder if that is kinked or pinched? However I go from here, it seems like it's inevitable that I'm dumping this oil change and cleaning it all up again; I will inspect that o-ring carefully. Thanks for the fiche pic, I hadn't thought of that as the next step in the failure tree (was thinking of the technical manual but parts fiche is a lot more accessible!)
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  7. Boatman

    Boatman Membership has it's privileges ;-)

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    Green :huh,,,,, I guess,,, I'm color blind.


    Make sure the gasket is seated on the base of the screen properly.

    Looking at your pic again, one thing I noticed is you have wet oil higher than the connection. Are you sure the leak isn't higher? Clean it all up, puff some baby powder on it and keep a close eye.
    #7
  8. Dusty

    Dusty Long timer

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    I put in one of the kits in last fall and i had a bad green seal that goes on the screen, it was hard to see the flaw... I put the old one back in and all was good.

    my .02
    #8
  9. DirtyADV

    DirtyADV Long timer

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    What about the return hoses from the front valve cover going back to the oil tank. Have seen those quite worn from rubbing against stuff, especially the left side rubbing against the fan cover.

    /Johan
    #9
  10. Sumi

    Sumi Long timer

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    I also had a faulty brand new green gasket last year, which made an exactly same leak. I've changed it for a new one and put a hint of silicone on it while installing - I didn't drain the oil just layed the bike on it's side - asking a friend to hold a rag in the hole while the screen was out of the reservoir (because thats when oil is pouring out). Job was done in 15mins, and lost only about 0.2l oil. No leak since.
    #10
  11. kcc

    kcc Been here awhile

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    Awesome... This sounds like the first procedure for sure.
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  12. kcc

    kcc Been here awhile

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    As usual, good tips from inmates.

    I have an oil sucker so I pulled out a liter or so of oil from the top tank, laid the bike on the right side, and changed out that green o-ring without spilling more than a tablespoon of oil.

    I found the old o-ring had a very visible defect on one side. I oiled the new one and inserted it after inspection, and buttoned everything up, and it looks like I'm now leak free! :clap

    Thanks to those with inputs, my garage floor appreciates it.
    #12