Replacing valve stem seals: Anyone ever do it?

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

  1. TheMuffinMan

    TheMuffinMan Forest Ranger Magnet

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    Heck yeah, that's definitely valve stem steals. I'm looking forward to more!

    :lurk

    Oh and I get the unheated garage. Mine is unheated and I've been slacking on getting my 525 back together (so I can then start work in the 950 :lol3).
    #41
  2. wiseblood

    wiseblood OK, boomer Supporter

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    Hey Doc! :fyyff



    1. Yes, it's probably me. First, as you know, I'm not exactly what the motorcycle manufacturers had in mind when they designed their vehicles. I'm trying to get a gig battle-testing motorcycles. If anyone at KTM wants to true endurance test (Dakar? Pfffffft. Too easy!) give me a bike for a couple years. I'll ride it with my sasquash-self every day, commuting in the shittiest roads in the Northeast, in the coldest/hottest/wettest weather. I'll even get it knocked over a few times by cars. Want an ABS test, too? I can do that. :nod :thumb

    2. Lemon law applies only to dealers, not to private sales. Also, this bike kicks ass! :ricky

    As far as hiring a "professional" -- aside from saving money, I like to build up my wrenching skills. I was raised by folks who were not very mechanical (though, my mother as an artist/sculptor does have an impressive wood workshop!). I discovered late in life that wrenching on bikes is a very satisfying thing! Especially when I manage to fix it, and not break it more. :augie
    #42
  3. mechcanico

    mechcanico Adventurer

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    Hello , that plug is heavily oil fouled , i am not convinced that that is all from valve stem seals , there is no white oil ash build up on the plug that you get with excessive oil burning .

    The other plug doesnt look so bad yet the valves and seals have only done the same work and are the same age .

    Have you done a compression test ?
    Does the crankcase breather system 'favour' a particular cylinder ?
    Does there seem excessive crankcase pressure ?
    Is the breather system working properly , is there seperator gauze in the pipe work to take the oil mist out of suspense before it gets to the air box .

    Is the air box standard or has it had any modifications , was there oil in the air box

    I have done valve seals on car engines where the seals have not been wiping the valve what so ever and the plugs have not been that badly oil fouled .

    Does it smoke under load aswell as on the over run , is the bike using alot of oil
    #43
  4. Rharr

    Rharr Been here awhile

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    Smoke on over run aka engine breaking from higher revs will be the tell tale sign of a bad valve seal. Do the guys you ride with joke and call you for mosquito abatement?

    Engine breaking at high rpm with throttle shut will create a lot of vacuum and will pull oil past the seals if they are bad.
    #44
  5. wiseblood

    wiseblood OK, boomer Supporter

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    I'm still chugging away at this. Work & family pulls me away for a bit, but I'll get there..... eventually! :hide

    So, since last I posted, I finally got the damn exhaust off. The clamp bolt which connects the small rear header pipe to the rest of the exhaust was a solid block of rust. I finally got the pipes off by removing the oil tank and swinging the pipes around to the left side and dropping it through the swingarm.

    Anyway, here's what I did so far:

    Leak down test. Rear cylinder (the one which is fouling the plugs!) actually had good seal. Only 4-5% leaking, and that was past the rings. (Coming out of the crank case breather, to be specific. :deal)

    The FRONT cylinder, OTOH, was a bit more problematic. On that one, I am getting 9-10% loss, and it's coming from the intake valves. :bluduh I created a separate thread for that. Question I had was, "should I renew the head & valves?" General consensus seems to be "ride it like you stole it. It's probably nothing." Here's to hope! :freaky

    Valve clearance check. Seven of the eight were spot-on. The right side, rear, exhaust was a little tight, by about 0.05mm. (Was between 0.2 and 0.25 -- should be between 0.25 and 0.3.)

    Before I left the garage last night I took a look into the exhaust to check out the valves. I saw a LOT of carbon. Is this normal? Plus, the front cylinder valves had what appeared to be some white calcified crap on the stems. Anyone have a clue what this might be? The exhaust valves don't seem to be leaking. Any suggestions?

    Pictures of front exhaust & valves:

    [​IMG]

    [​IMG]


    Pictures of rear exhaust & valves:

    [​IMG]
    #45
  6. Bowber

    Bowber Been here awhile

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    Not much help with the look of the valve stems but I've changed valve stem seals on a DR350 in situ, bit harder on the KTM though as the valves are down in the bucket holes but it's doable.

    I'd be looking at the rings as well, get your bore scope in the bore and check for marks left by a broken ring.

    Steve
    #46
  7. wiseblood

    wiseblood OK, boomer Supporter

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    That's gonna be my next step. I'm a little bit nervous, because (apparently) I'm a ham-handed gimp of a mechanic. But.... :lol3. What's the worst that can happen? :hide

    Good idea. I'll run it down the spark plug hole next time I'm at the garage.

    BTW... Piloting a borescope is friggin hard! :jerko
    #47
  8. wiseblood

    wiseblood OK, boomer Supporter

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    Did I mention that I work slow? :fpalm

    So, I finally dropped the motor last night:

    [​IMG]

    [​IMG]

    [​IMG]

    I confirmed the valve clearances. Tonight I'm planning on going back to the garage and finally pulling the cams and replacing those stem seals. :clap


    By the way: I had a plan for a bit in which I would remove all the bolts except the swing arm, which I would just loosen, and then rotate the engine down in front. The benefit of that would be getting access to the rear cylinder without having to completely remove the engine. That won't work. :nono

    The engine, it turns out, rests on the frame, preventing it from rotating down in front. You can see that a bit in the first picture above, and also in this picture:

    [​IMG]

    The cross piece below the swingarm bolt prevents the engine from pivoting. So, anyone who wants to replace the seals should assume they have to remove the motor (unless you have a smaller tool for pulling the valve keepers/springs).
    #48
  9. DirtyADV

    DirtyADV Long timer

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    Remove the swingarm axle and it can be rotated down on the lower engine mount enough to lift rear cylinder.

    [​IMG]

    /Johan
    #49
  10. wiseblood

    wiseblood OK, boomer Supporter

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    Top End Selfie...

    [​IMG]

    :lol3
    #50
  11. TheMuffinMan

    TheMuffinMan Forest Ranger Magnet

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    Nice! :clap
    #51
  12. wiseblood

    wiseblood OK, boomer Supporter

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    In my situation, the only reason I was trying not to remove the engine was to avoid removing the swingarm. But, it turned out to not be that big a deal. (Bike didn't fall over or apart.)

    Certainly a heck of a lot easier to work on now! :freaky
    #52
  13. wiseblood

    wiseblood OK, boomer Supporter

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    I found this interesting... probably old hat to most of you, though.

    Cam bridge underside:

    [​IMG]

    Very interesting how the oil travels to the cam lobes. You can see where the passages are next to the big bolt holes on the head:

    [​IMG]

    I guess the oil returns by spilling down the vertical space where the cam chain lives.

    Anyhoo, I'm up to the hard bit. Was too late to get to it last night (11:30 pm on a work night), but I'll be getting to the seals in the next couple days.

    [​IMG]
    #53
  14. wiseblood

    wiseblood OK, boomer Supporter

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    Hey All --

    So, worked last night to remove the valve keepers and springs. I has planned to get through them all in one night, but the process of removing the keepers, and even more so INSTALLING them has been difficult.

    Here's a video of the attempts and process.

    First shot:



    :lol3

    Now, actually getting one out:




    So, here was the removal process:

    1. Remove cams & buckets/shims.
    2. Using a threaded air hose, pump 50-70 psi into the cylinder.
    3. Using valve keeper remover/installer tool, carefully (but firmly!) tap to remove keepers.
    4. Remove retainer and springs
    5. Extract old seal
    6. Install new one (coat w/ oil to avoid damaging seal)

    Installation was SUPPOSED to be:

    1. Pump 50-70 psi into cylinder.
    2. Install springs.
    3. Put keepers into retainer, and place retainer/keepers in place on top of springs.
    4. Using valve keeper remover/installer tool, push firmly down until keepers lock into place.
    5. Drink beer.

    This did not happen. :bluduh

    I have not yet been able to get the keepers back in place for the one valve I removed. One lesson learned, however: You can remove air pressure from cylinder without any risk of losing a valve (assuming you're at TDC). First, valve only will move maybe half an inch down before resting on the piston. Second, there is enough drag from the seals and guides that the valve will stay put unless you physically move it.

    In fact, I'd say, this is an excellent time to see if you have any free play in your valve guides! My right, rear exhaust valve guide appears good: Zero play at all.
    #54
  15. wiseblood

    wiseblood OK, boomer Supporter

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    Here's what you see when you do finally get the keepers off:

    [​IMG]

    Magnet inside tool catches keepers, which is what you see inside the tool.

    Down the rabbit hole:

    [​IMG]

    You can see the valve oil seals at the bottom of the stem. You need some long grabby tool to get it out:

    [​IMG]

    [​IMG]

    Seal removed:

    [​IMG]

    You can see some wear at the top. I never know how to evaluate these things, but you're looking at the seal which caused the most leakage:

    [​IMG]
    #55
  16. unaweep

    unaweep Uses lotsa band-aids

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    Is the valve keeper remover tool necessary for this motor? Or, can any valve spring compressor tool be used?
    #56
  17. Rharr

    Rharr Been here awhile

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    would it be easier to jerry rig up a spring compressor stand like this out of 2x's and bolt it to a table?

    https://youtu.be/up00AC7QcZs?t=59

    FYI, triple check the valve guide after you get the seal off to make sure there is no rubber remnants from the old seal stuck on the guide anywhere.
    #57
  18. wiseblood

    wiseblood OK, boomer Supporter

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    Valve spring compressors usually need you to remove the heads. But, no, a regular compressor will work.
    #58
  19. wiseblood

    wiseblood OK, boomer Supporter

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    Good tip about checking for old rubber!

    That bench compressor is pretty awesome!
    #59
  20. unaweep

    unaweep Uses lotsa band-aids

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    Thanks. I really don't want to remove the heads if I don't have to. $50 for the tool is cheap if it means I don't have to do that. :thumb
    #60