Replacing valve stem seals: Anyone ever do it?

Discussion in 'Dakar champion (950/990)' started by wiseblood, Jan 30, 2015.

  1. wiseblood

    wiseblood OK, boomer Supporter

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    I guess the way it would hurt to try is if the valve drops into the damn cylinder. :bluduh :lol3

    (For the win: Valve drops, air blasts out, blowing the valve collets somewhere in my garage. :lol3 :thumb)
    #21
  2. rider911

    rider911 Shortcut Navigator

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    I have replaced the seals without removing the head.

    I used compressed air and made up a lever arrangement to compress the springs. This is not an uncommon thing to do, contrary to what all the "experts" here are saying.

    I had a brand new 990 2012 that was using oil and I was suss on the valve seals. I think it took a couple of hours to make the lever and do the job. I did it by my self but would have been 10 times easier with another pair of hands.
    #22
  3. rider911

    rider911 Shortcut Navigator

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    Even if you lost air pressure, the valve can only fall a faction at TDC





    .
    #23
  4. Chuckracer

    Chuckracer Jerkus Maximus

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    Use the KTM crank lock bolt to lock the cylinder at TDC...no need for air pressure or rope.
    #24
  5. Oldebonz

    Oldebonz Been here awhile

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    Air or rope must be in combustion chamber or there will be no resistance to hold valve when compressing spring to get retainer and collets off,whole assembly will move till valve contacts piston,probably won't drop in but metal to metal contact could possibly harm something.
    #25
  6. wiseblood

    wiseblood OK, boomer Supporter

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    First, I'd like to say that you're all bad people for encouraging me to do this insanity. :D

    The keeper removal / installation tool seems like it would make getting the spring off pretty easy:

    http://youtu.be/-zvH7xiU0KQ

    Tool is less than $50, which is less than the cost of the gaskets on only one cylinder.

    That being said: How did you pull the seals out? How hard was that to do?

    Also, did it fix your problem?

    Thanks, you bastards. :lol3
    #26
  7. wiseblood

    wiseblood OK, boomer Supporter

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    This. :nod
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  8. rider911

    rider911 Shortcut Navigator

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    that tool is a ripper but I'm not sure you would get it on the rear exhausts. You may be able to cut it down though and make a lever arrangement to operate it. I think I took a pic of the tool I made so i'll see if I can dig it up.
    I used a leakdown tester to put air in the cylinder.

    The seals have very little interference so getting them off was a lot easier than I expected. I think I just levered them with a screw driver. I made a little tool in the lathe to install the new seals so as not to damage the seal but it was not probably necessary. Just use some lube.

    Considering this was a brand new bike the seals were not worn out but I found a slither of rubber under two seals. At the same time I switched back to mineral oil and the problem went away. So I can't say definitively that the seal was the whole cause of the oil consumption.

    I was going to do a valve check anyway so it took very little extra work to change the seals and rule out a possibility that would probably keep bugging me if I didn't do it.
    #28
  9. AdvRonski

    AdvRonski They call me......Ronski

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    I used an exhaust spring puller hook tool to remove the valve seals. Just hook an edge and pull them out.
    I pulled my engine down for the same reason, increased oil consumption and puffs of blue smoke. At 34k miles since last tear-down, I found the rings worn to their limit, with end gaps at .50mm. There was also a lot of oil residue on the exhaust valves. The breather seal was fine, but now it's getting the full treatment. Rings, valves, breather seal, and just for fun, SD cams.
    I remember reading about a dirt-track racing team that runs a 950 engine. They said the bottom end is beefy enough for 200 HP, so it never needs much work, but they put new rings in rather frequently.
    #29
  10. wiseblood

    wiseblood OK, boomer Supporter

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    Well, you know what they say...

    [​IMG]

    :D

    Sounds like you dropped the motor from the frame for the work. I'm thinking about that.

    I haven't decided yet how far I want to get into it. Gonna to the valve check/adjust and then make a decision about everything else. Seems that IF I can get the tool in there to fit, removing the valve springs/keepers would be easy enough, but w/o pulling the engine, that might not be possible.

    My problem is that I'm not more than a "shade tree" mechanic, so this is a big job for me. And, I work SLOOOOOOOOOOW. :snore
    #30
  11. AdvRonski

    AdvRonski They call me......Ronski

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    Well, it's the perfect time of year to tear it all down. The winters are long here in Minnesota, anyway.

    [​IMG]
    #31
    SunshineTom likes this.
  12. TheMuffinMan

    TheMuffinMan Forest Ranger Magnet

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    Day 1 Get plastics off, strip down to basically valve check level. Day 2 drop engine. Day 3 pop heads off and replace valves easily. Day 4 reinstall engine in bike, Day 5 put everything else back on. Five days maybe 3 hours per day at a slow pace.

    I find braking down big jobs into little tasks makes things seem more manageable. YMMV
    #32
  13. Keith

    Keith Slabbing it

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    Air pressure is the preferred method in the car world. It'll keep the valves again their seats. The hard part would be the narrow spark plug well on the LC8.
    #33
  14. wiseblood

    wiseblood OK, boomer Supporter

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    Thanks great advice, right there! :nod :thumb

    Thanks! :beer
    #34
  15. wiseblood

    wiseblood OK, boomer Supporter

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    I have a compression tester which I think ought to work well enough.

    If I go and do this thing, I'll try my best to document the procedure and take pictures. Weather in NYC is pretty bad today and this week, so I don't expect to be able to get to my garage (which is a few miles from my house) for a few days. But, I'm homeful I can make this work.
    #35
  16. wiseblood

    wiseblood OK, boomer Supporter

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    Probably a stupid question.... Has anyone tried this stuff?:

    [​IMG]

    http://www.amazon.com/ATP-AT-205-Re-Seal-Stops-Bottle/dp/B000NVW1LM/ref=cm_cr_pr_product_top

    ATP AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle


    My first instinct is that this is snake oil :topes, and running it in a high-performance, small engine like the LC8 might really mess things up. I'm sure it doesn't lubricate like proper oil, so what is i gonna do to all the small passages and bearings, and what about the wet clutch?

    That being said... if it isn't dangerous BS, I thought I'd at least ask. Any thoughts?
    #36
  17. wiseblood

    wiseblood OK, boomer Supporter

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    I'm finally getting around to working on the bike. It's been cold in NYC! :vardy (Did I mention my garage is unheated?)


    So, bike is now stripped down pretty good. Rather than tie back the carbs, I just removed them entirely. I have in mind to do the headstock bearings, so I might as well get things tidy:

    [​IMG]


    Check out the plugs:

    [​IMG]

    Rear plug on the left, front on the right. Notice the oil fouling! And, I just replaced that plug a month before I parked the bike for service. :eek1


    Looking down the rear intake, I see oil sitting on top of the valve:

    [​IMG]

    This seems to pretty clearly indicate that the rear intake (at least) is leaking oil. :nod
    #37
  18. rider911

    rider911 Shortcut Navigator

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    good work :thumb
    #38
  19. docgonzo

    docgonzo Old Gadfly

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    Jesse, if you needed your appendix removed, would you do it yourself? That's why they have professionals! :wink:

    Two observations:
    1. You have bad luck with motorcycles.... Didn't you go through a few rebuilds with your Triumph? How much of that work did you do yourself?

    2. The bike has 21,000 miles? That's like break in miles. You should have documented the oil burning problem from the beginning, and invoked the Lemon Law on the bike....




    :hide
    #39
  20. unaweep

    unaweep Uses lotsa band-aids

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    Eager to watch this play out. I'm going to do the same on my SE at some point. Appreciate the photography. :thumb
    #40