HELP!! F**KED my LC4 cam

Discussion in 'Thumpers' started by Dotbond, Nov 19, 2007.

  1. tdreyer

    tdreyer KTiM

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    I just went out and looked at the cam bearings I replaced from my 2 previous intake roller failures. The 2 big roller bearings i have are both marked "Japan" and came in a KTM box. They are also sealed on both sides. The smaller needle bearings are both marked "Germany". I think a PO must have replaced that bearing in the past?

    Maybe it's just the pic but that intake roller looks scored? Both of mine were locked up and ground up themselves and the intake lobe of the camshaft.

    Good call, in my book, on going ahead and replacing those rollers. Are you going to rebuild the water pump as well?

  2. Sparrowhawk

    Sparrowhawk Long timer

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    The photo of the rocker arms isn't mine. I stole it from an earlier post just for illustration. My rollers look and feel good as new but I'm still changing them out since I have the cover off. The water pump rebuild is on the to-do list for the same reason - cheap insurance against a failure in the middle of a future long trip.

    Sent from my SCH-I535 using Tapatalk 2
  3. Droptarotter

    Droptarotter Long timer

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    Thoughts on the sealed camshaft bearings...............

    When I did the camshaft bearings on my 520 EXC, I found the bearing to be shielded, not sealed. I thought this odd as this was the first time I had run into a bearing done like that inside a motor.

    I did a little experiment to see if the shielded bearing would get oil. I put enough engine oil in a cup, then tossed the shielded bearing in the cup and bubbles immediatley started coming out of the bearing..........so oil was getting into the balls very quickly. I installed the new bearings with the shields on.

    That was years ago and the 520 has 100's of hours on it since then.

    A couple of things I learned afterward...........sealed bearings are like what you would use in a wheel bearing........the only lube they get is what is packed in them.

    Shielded bearings are used to keep the debris out, but let oil/lube inside to the balls and are common inside motors.

    If the new bearings come with a shield, I would leave it in place and install the bearings that way.

    Cheers
  4. Sparrowhawk

    Sparrowhawk Long timer

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    The replacement cam bearing, KTM part # 0625060040 pictured below, came as an NTN 6004LU. NTN describes this as a "single row radial ball bearing 600 series, pressed steel cage, double lip contact rubber seal one side, Shell Dolium R" Dolium R is a bearing grease made by Shell. Cross references for the bearing include SKF 6004 RSJ (old RS1) and NSK 6004DU. All of these indicate a one-sided seal. The bearing itself, however, has an identical looking rubber seal and markings on both sides. Go figure. In it goes.

    [​IMG]
  5. gunnerbuck

    gunnerbuck Island Hopper

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    I've been running an SKF cam bearing for over 30K KM with little issue... Below is a spiel taken from my rebuild thread:


    I did a little research on the cam ball bearing {6004} and found out that the same bearing in the NTN brand are also used as wheel bearings in some Honda motorcycles... These bearings when ordered for the Honda application also have the TMB 004 stamp on the outer race.... With this info I called the bearing shop and let him run the numbers and he came back with the SKF 6004-2rsh/c3 as a direct replacement... So we'll give her a go and see if the price saving was worth it....

    [​IMG]
    Here are the new cam related parts ...
  6. Tseta

    Tseta Lost

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    Regarding the cam ball bearing, I'd like to point out back to one of my earlier posts in this thread: http://www.advrider.com/forums/showpost.php?p=12784571&postcount=42

    Especially this part, about the TMB-nomenclature in the KTM part description and also visible on the actual bearing itself:

    So, it's (perhaps) not so simple, afterall...

    Cheers,

    Tseta
  7. Umarth

    Umarth Been here awhile

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    Quick question,

    I've just rebuilt my water pump and also replaced the cam shaft.
    While putting it back together, the manual states??:
    1. Put in cam shaft bolt and torque to x nm.
    2. Un'screew camshaft bolt so that slot is vertical.

    Wtf? Why do I need to torque it if I end up loosening it?
    During the procedure, the locking bolt is in the crack shaft, o there is no way to turn that cam shaft bolt without loosening it...
  8. gunnerbuck

    gunnerbuck Island Hopper

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    Some times the shop manual is a bit foggy...

    Here's what you do:
    1. Tighten the cam shaft sprocket retaining bolt to the required torque with the locking bolt in place..
    2. Remove the locking bolt and turn the engine over until the slot is vertical..
    3. Slip the waterpump into place...

    4. Turn the engine around till the cam lobes are facing downward so they don't interfere with the replacement of the rocker cover...
  9. Umarth

    Umarth Been here awhile

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    :splatAh crap!!
    The whole things has been closed up (Honda bound gasket curing as we sleek)
    Looks like I'll be starting over next week end...

    Thanks gunner...
  10. gunnerbuck

    gunnerbuck Island Hopper

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    Good thing you caught it because running around with a loose cam sprocket/bolt is a recipe for disaster... This link might help:http://advrider.com/forums/showpost.php?p=14584812&postcount=115

    One other question for you, did you remember to slack off the cam chain tensioner upon disassembly and then reset the plunger after everything was back together?
  11. Sparrowhawk

    Sparrowhawk Long timer

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    I ran into a stopping point last night trying to put the camshaft back into position. With the new ball bearing slid onto the cam and metal ring in place, I am not able to either tilt the end of the cam down far enough or raise the cam sprocket high enough to slide the splines into the sprocket. I can't put the bearing in place and then slide the cam through the bearing and into the sprocket because there isn't enough room on the other end of the cam. The chain tensioner is removed.

    Any ideas? What's the trick?
  12. gunnerbuck

    gunnerbuck Island Hopper

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    It is a finicky process to get the 3 together as one and takes a bit of trickery..

    What I do is put the chain on the sprocket and hold the retaining ring against the sprocket rather than putting it in it's seat... Then I partly slide the cam into the bearing so the end will tilt up {make sure the needle bearing is also installed} keeping an eye out that the index mark on the shaft lines up to the sprocket mark... Then I work the shaft splines into the sprocket and also move the clip so it fits into the seat, be so carefull not to drop the clip down the cam chain tunnel...
  13. Umarth

    Umarth Been here awhile

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    That's how I did it last week and it worked like a charm. Took like 2-3min to get it back in place.
  14. bmwktmbill

    bmwktmbill Traveler

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    I dropped the washer on the sprocket bolt down the tunnel.

    It was a nightmare to find as it went back behind the balancer or some such.

    Also I have jammed up the chain when I dropped it and had to remove the clutch cover to free it.

    Just saying...I'd stuff the tunnel with something like paper towel or cut a chunk of cardboard to block.

    bill
  15. Umarth

    Umarth Been here awhile

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    Dido on the chain jamming in the bottom part.
  16. Sparrowhawk

    Sparrowhawk Long timer

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    That is a nightmare I was worried about.

    Thanks for the hint. I"ll try it again with less beer and better light. :) My shop is an old storage room and not the best for tricky tasks.

    Sent from my SCH-I535 using Tapatalk 2
  17. gunnerbuck

    gunnerbuck Island Hopper

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    Your shop sounds like a dream compared to mine...
  18. Sparrowhawk

    Sparrowhawk Long timer

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    Thanks much for the instructions. With a rag placed in the cam chain tunnel and the retaining ring held to the sprocket with a dab of grease
    it all went back together. Getting the splines aligned was still difficult.

    [​IMG]

    Everything was in place, lubricated, and lined up at what seemed like the right angle but it refused to go in. Adjusted the alignment and still no go. Tried different angles without success. Kept trying with small adjustments, pushing, adjusting, changing angle, pushing, and finally the shaft slid in with a satisfying smoothness to the hilt just like the the parts were made for each other, giving me a wonderful feeling of joy and success. :D


    I'm not complaining about having a roof, four walls, and electricity. It's just a little cramped at times.

    [​IMG]

    Sent from my SCH-I535 using Tapatalk 2
  19. muttley92

    muttley92 Adventurer

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    So I'm building an LC4 engine into an RS 125 as a project. But the engine seems to have seen better days. I've already replaced the starter clutch, now that it's run for long enough it makes horrible noises. http://www.youtube.com/watch?v=uSKuxUwipiQ. Believing it to the the cam follows I removed the rocker cover and found a camshaft with a big chunk missing and this. http://www.youtube.com/watch?v=aqR0PApUiHs&feature=youtu.be Can anyone confirm if this part can replaced seperately? and what may have caused this? Should also mention that the rocker cover was pretty well sealed on and whoever did it has got sealant all over the valves. :clap
  20. Alik

    Alik viertaKTMotor *****

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    The autodecomp ring seems to be broken. I wonder how the cam followers do look a like... The ring can be replaced AFAIR. but one have to examine the shaft itself. The pin under the autodeco ring could be damaged too.