Three times the fun! (LC4 HOWDID)

Discussion in 'Thumpers' started by Tseta, Oct 13, 2010.

  1. Tseta

    Tseta Lost

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    In this thread, I will be posting some photographs and random observations about various KTM related maintenance topics that I will encounter during this winter. This thread will probably receive it's updates as periodic bursts, instead of a steady stream, since I'll only be able to focus on the bikes on longer holidays.

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    Well well well, boys and girls! It's that time of the year again. The regular riding season here in Finland is almost over ( :cry ), which means that many bikes will be needing their "routine maintenance". As I have the privilege and duty to keep three LC4s in running order, I thought I'd share some of the mayhem and carnage with you guys.

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    This year I am well prepared for the mid-winter urge to go riding. :deal

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    This site is only as good as we make it. So, once again, I would like to take the opportunity to thank the inmates here for the various guides, insightful advice and fascinating discussion.

    Cheers,

    Tseta
    #1
  2. Tseta

    Tseta Lost

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    Today I started on the blue Adventure. It is the oldest of the bunch, a 1998, with about 50,000 kilometers on it. The current owner bought it just this summer and has only driven it about 1000 kms. The bike is a bit rough around the edges and the age is surely starting to show.

    The '98 LC4s have the old style mainshaft bearing. However, the previous owner claims that the bearing swap has already been performed. Not much other service history is available for this bike. So, it's time to open her up and see what's up.

    First order of business was to drain the oil. Things started looking quite grim. :uhoh

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    There was a lot of metal shavings (even for a LC4...) on the screen and on the magnets. The oil seemed to also have some sparkle to it. :eek1

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    This magnet seems to have many larger metal pieces on it. Some of the pieces' outlines remind me suspiciously of the profile of a tooth on a gearwheel. However, these pieces are quite thin in cross-section.

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    These are two of the larger bits found on the magnets. The other looks like the edge/corner of a tooth from a gear wheel. The other looks like a miniature solid rivet. The head has a distinct mushroom shape and the shaft shows a break surface. The diameter of the pin is too small for it to be from any needle bearing, though.

    I have a feeling this is going to get expensive. :puke1

    -T
    #2
  3. makazica

    makazica Been here awhile

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    I'm truly jelous! Three LC4's to screw with....

    :clap

    Why do you all have your fork protectors pulled all the way up?
    #3
  4. dlh62c

    dlh62c Long timer

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    My guess is.....somebody installed the forks upside down.

    daryl
    #4
  5. NICO

    NICO Long timer

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    It's Finland. He's trying to keep the bike's legs warm. :D
    #5
  6. Tseta

    Tseta Lost

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    The reasons for having the fork protectors all the way up are varied.

    For the blue Adventure, it is because it has 50mm WP Extreme forks, which are conventional (RSU). Thus, the chrome tubes that need protecting from stones and such are on top, and the neoprene socks are there to protect them.

    For the gray and orange Adventure with the USD forks, the idea is a bit more complicated. They already have the plastic fork guards to protect the lower chrome tubes. If the neoprene was all the way down, it would bunch up when the forks compress. The spokes then rub on the bunched up neoprene, wearing it out. The neoprene socks are low enough to nicely sweep about 5cm below the fork dust seal. Thus they function as a crude tertiary seal/mudflinger on the chrome tube, getting rid of the largest dirt particles before they go to the actual fork seals. Finally, the neoprene also protects the "soft" aluminum uppers from rock damage from roost and such.

    I realized today that the small rivet looking thing is from a bearing. It is one of those rivets that keeps the cage of a ball bearing together. Not good...

    -T
    #6
  7. makazica

    makazica Been here awhile

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    Thumbs up for the neoprene protectors....

    Rivet.....not good.....
    #7
  8. Tseta

    Tseta Lost

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    [​IMG]

    I continued working on the blue Adventure today. I found out many things, mostly unpleasant. I can't say that all of them came as a big surprise though, the issues are well known and documented.

    For example, the cylinder head top section seems to be leaking oil from several spots.

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    The camchain tensioner is leaking as well.

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    Somebody has tried to stop some leaks here with a generous application of goop.

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    One of the radiator mounts had broken. More work for my trusty MIG.

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    And this is what completely stumped me today.

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    Something as simple as the swingarm shaft/bolt. It won't budge. I tried gentle tapping, some heavier knocking and all-out swinging on it with a BFH. I tried heat, cold and penetrating oil. The bolt has not moved one millimeter. I'm eyeing the sawzall in the corner of the garage. The bolt WILL come out, one way or another...

    So, while the penetrating oil is soaking, I measured the valve clearances. They were all out of spec. My thinnest blade is 0.08mm, and it didn't fit for any of the valves. Also, the exhaust rocker arm axial play was about twice the allowed amount (0.2-0.3mm). However, the intake side was fine. The countershaft has about 0.4mm of axial play in it as well.

    I also performed a crude leakdown test. It seems that there is about 5% leakdown, and it sounds like most of it is leaking to the intake manifold.

    I am waiting in horror what damage will be found from inside the engine.

    -T
    #8
  9. laramie LC4

    laramie LC4 crash test dummy!

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    i think we have all had the joy of fixing the tank mounts. if you havent done it yet, you will....

    this is my version of the repair. i promise i wont be breaking anymore.

    [​IMG]
    #9
  10. DaBit

    DaBit Been here awhile

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    three? :eek1
    Wow, only one already keeps me busy!
    #10
  11. makazica

    makazica Been here awhile

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    Don't whanna be a smart ass but most of the oil leaks here seem to come from vents that aren't tightened properly....

    Also, I had the same problems with the swingarm / shaft bolt on a Husaberg that had crushed bearings inside the swingarm....so check that too...

    M.
    #11
  12. wrk2surf

    wrk2surf on the gas or brakes

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    be carefull not to start a fire inside the frame tube when welding those mounts... just doing the same to mine... freind thinks we should purge the tube with argon while welding.. think I will use a brace or pipe between the two rad mounts on mine.. mine has leaks all over too..
    #12
  13. dlh62c

    dlh62c Long timer

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    While your in there....inspect/replace the exhaust flange gaskets. Mine was leaking.....didn't hear a thing.

    daryl

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    #13
  14. Tseta

    Tseta Lost

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    DaBit: Only the gray KTM is mine. The other two belong to my buddies. I would have my hands full with doing regular maintenance on just my own bike. However, with this arrangement, I will have a bit more money for gas, tires and spare parts.

    Laramie: Solid looking welds there! :thumb

    wrk2surf: Thanks for the good tip. I will have to be careful when welding the frame.

    dlh62c: I think I will be replacing any and all gaskets on this engine...

    Makazica: :wave

    ----

    So, the swingarm pivot bolt finally broke loose, but not before plenty of "power" words were said. It was rusted solid, not a pretty sight. Also mangled the pivot bolt's nut in the process and the frame has some additional scratches on it.

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    I was then able to lift the engine out of the frame

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    and onto the table.

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    I then spent some time on making a pivoting LC4 engine stand. Time consuming work, but hopefully it will pay off with added convenience and ergonomics when doing this and other LC4 engines.

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    Oh yeah, be sure to check out my first trip report!

    Cheers,

    Tseta
    #14
  15. makazica

    makazica Been here awhile

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    I'm really really enjoying this.....:clap

    M.
    #15
  16. grimripper

    grimripper 1pissanter

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    It's great to watch someone who knows what their doing :D
    #16
  17. imaybail

    imaybail Been here awhile

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    Yeah, I'm subscribed fershur.
    #17
  18. wrk2surf

    wrk2surf on the gas or brakes

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    its funny the way the 02 has the newer color bottom end .. cases etc but no high flow head.. the older black head... in between year..

    we just made a stand as well.. nice one you got..

    make sure when you get the gasket kit it has at least two colors case gaskets as my buddy a machinist had problems shimming the crank and his only had one black gasket ... mine had two or three thicknesses including a green one.. we have actually sent both motors to a ktm shop (malcolm smith) as the shimming is not going easy.. maybe on our 3rd motor we will understand the black magic of shimming...

    always good work tseta
    #18
  19. makazica

    makazica Been here awhile

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    My friend had an '02 but his didn't have the gray engine, it was completely black, same as my '01....interesting....

    Not to hijack Tseta's thread but how difficult would it be to mount a High flow head to a '01 or '02 bike?

    And yes, always good work!!

    M.
    #19
  20. laramie LC4

    laramie LC4 crash test dummy!

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    aint that the truth. that was the hardest part when i rebuilt mine as well. plus, unless you have the magic KTM tool, you only get one shot. if you didnt shim right the first time, getting those bearing races back off is not easy. we tried everything. i finally sent mine to Chip and had him do it for me, he had the correct tool and it took him a few secs.

    love the engine frame/stand you built, that will make life a lot easier.

    laters,

    laramie :beer
    #20