HELP!! F**KED my LC4 cam

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

  1. Dotbond

    Dotbond Africa, Africa

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    [​IMG]
    Did a weekend ride and tappit noise came back about 100km into the ride.
    Didn't think much of it.
    Just pulled the rocker cover and the inlet cam follower bearing had siezed and has worn the inlet cam lobe about 1mm.:cry
    What to do??
    [​IMG]

    Bike has done 15,500km. Regular oil and filter changes changes. 2004 model.
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    #1
  2. JSL

    JSL Adventurer

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    You need a new cam and the cam follower bearing (no? really!?). This happened to me this fall after about 28600km, though the damage was not nearly as bad. I suggest that you replace both cam follower bearings while you're at it. I replaced only the broken one and the tapping noise came back after ~1000km so I'll have to open it again some time soon.

    The new (standard) cam is ~150 euros and the bearings are ~20 euros each. I've been told that a damaged cam may also be fixed by the same shops that do cam tuning.
    #2
  3. bmwktmbill

    bmwktmbill Traveler

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    Dotbond,
    That sucks, I just wrote a bunch of good stuff about KTM 640 reliability. I take it all back....
    Make sure you peen the shafts for the new bearings in place. I didn't and paid for it when the shaft drifted out and raised a little hell.
    Run a magnet around in the recesses. Check the water pump.
    b.
    #3
  4. rob748

    rob748 resident alien !!!!

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    mine did this at about 15000, do the water pump seal while you have it open
    #4
  5. whitezw

    whitezw General Flunky and Grunt

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    I have a cam from a 1997 LC4 if you are interested...

    Thanks,
    Zeb
    #5
  6. Zerodog

    Zerodog Long timer

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    Dude that sucks. Get a rally cam while you are at it:wink:.
    #6
  7. Spam16v

    Spam16v Squid Rocket

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    good excuse to spend money for more power while it's apart if you ask me... look on the bright side b/c focusing on the negative just sucks.
    #7
  8. Dotbond

    Dotbond Africa, Africa

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    And i suppose you "know" someone who does them.....?:lol3

    Serious couple of questions here.
    1. Will i need to strip the motor down to check it out or will just flushing and changing the oil and filters suffice? I am a student for the next 2 years - poor.

    2. Any body heard of getting the cam repaired?

    3. Do i replace the cam bearings with KTM ones or a known aftermarket brand?

    4. How do i get the cam out?

    Any words of wisdom welcome please.
    #8
  9. holycaveman

    holycaveman Long timer

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    Hmmm, look familiar Rob?:D
    #9
  10. gunnerbuck

    gunnerbuck Island Hopper

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    #1 If the bearing just seized and all the needle rollers are in place only fine particulate may of gone into the motor. If thats the case you may get away with just doing the repair along with with a few oil flushes. Pull the drain plugs and see what the magnets say...

    #2 I would say to just spring for the new part rather than trying to rebuild the old cam.

    #3 I don't know of any aftermarket follower bearings for the 640. The OEMs are not that costly and I think are your only option. They are a little tricky to replace as the bearings consist of loose needles and a pastic containment sleeve that slides out when the shaft is pushed thru. As Bill mentioned you will have to press the old shafts out {I used a ball joint removal press to do mine} as the shaft ends have been flared with a ringstamp. The new shafts can be pushed in by hand and the ends can be flared by carefully dimpling the shaft ends 6-8 times per end with a small centerpunch around the outside edges.

    #4 Use the crankshaft locking bolt to lock the shaft you can then loosen and remove the sprocket retaining bolt. Pry the bearing circlip up out of its groove. You then can tilt the cap bearing end of the camshaft up and slide the shaft out of the sprocket. Once clear of the sprocket the shaft, bearing and circlip can be lifted out together and a dowel can be put in the sprocket to hold it in place....
    #10
  11. Dotbond

    Dotbond Africa, Africa

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    [quote/]#4 Use the crankshaft locking bolt to lock the shaft you can then loosen and remove the sprocket retaining bolt. Pry the bearing circlip up out of its groove. You then can tilt the cap bearing end of the camshaft up and slide the shaft out of the sprocket. Once clear of the sprocket the shaft, bearing and circlip can be lifted out together and a dowel can be put in the sprocket to hold it in place....[/quote]

    Looks like i have a standard length bolt M8x16mm and 1mm thick washer according to the info about the bolt in the manual and i need a special tool.
    I suppose a longer bolt would be the go. An ideas on the length required?
    #11
  12. gunnerbuck

    gunnerbuck Island Hopper

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    I made one out of a stud that had 25+mms of thread. I ground about a 45 degree blunt point in the threaded end to engage the recess in the crank web and a screwdriver slot in the other to torque it in. You could use a bolt as well but may have to remove the filter anytime you wanted to use it. Leave a little flat on the end, in other words dont grind it to a full point and be carefull not to torque it in too hard and distort the crank... You can shine a flashlight into the hole to see the slot in the crankweb at TDC to see what shape to make your point....

    Just measuring up the KTM OEM locking screw and it has about 25mm of thread....

    Good luck...
    David...
    #12
  13. Dotbond

    Dotbond Africa, Africa

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    Thanks for that info. I found your post about this from last year but wasn't too sure.
    Will take a photo of the mesh filter to see the debri from the cam.
    There wasn't any sign of metal when removed the front spin on filter and drained the downtube.
    Lots of fine-ish metal and very fine dust like metal around the two bottom magnetic drain plugs tho.
    Haven't taken off the RH paper filter yet. Tomorrows job.

    Trev.
    #13
  14. bmwktmbill

    bmwktmbill Traveler

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    DB,
    The cam repair is prbably a spray weld hard coating. It might work if you are broke, I understand that problem. A good auto machine sop should be able to help and press in and peen your new cam followers.

    Don't give up.
    This is the bad luck.
    The engine really is tough.

    Use the magnet on the top end and change the oil in the lower end, use cheap stuff, run it for a bit and change it again. I would just do the lower end oil, not the main tube. It is filtered to get in there.

    Finially you can change everything and the filters and use good oil.
    b.
    #14
  15. gunnerbuck

    gunnerbuck Island Hopper

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    If you leave the paper filter on its side to drain you will most likely see some metalflake in the oil.. To test if the oiljet is clear from this filter to the piston I use a thumb lever oilcan to squirt some oil thru the banjo port above the TDC inspection window. A shot with an airgun will also tell you it's open...
    #15
  16. dorkpunch

    dorkpunch Oops...

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    if i'm not mistaken a new cam is only about $150. I think you'd be hard pressed to find a place to repair your cam for that.
    #16
  17. clintnz

    clintnz Trans-Global Chook Chaser

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    Bugger!

    I think I'm going to do those follower bearings on mine now, I've heard too many reports of them failing, esp around 40K km like mine is. The bikes off the road for a few weeks waiting for parts after the sheep incident so it's probably the ideal time to get it done. Might check the waterpump while we're in there too. $50 or $100 of parts is probably cheap peace of mind I reckon.

    Cheers
    Clint
    #17
  18. gunnerbuck

    gunnerbuck Island Hopper

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    I inspected my followers at 40 K and they still looked like new.... But I replaced them anyways , better safe than sorry...

    Another situation for changing them is if your bike has run low on oil for a spell. The followers are the highest thing in the engine and may be the first to feel the effects of oil deprivation...
    #18
  19. Dotbond

    Dotbond Africa, Africa

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    Photos of the Drain Plug with the mesh filter and the pan i drained the engine oil into showing the debris.
    Price for a new cam is $290 NZD
    Bearing is about $40 NZD
    Also got a guesstimate on the time needed to dissasemble the motor, clean and re-assemble was 8 - 10 hours work at the local KTM dealer at about $65/hr. F**k.
    A BMW dealership rate is cheaper than that!!
    Flushing the motor with oil a few times sounds like me.
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    #19
  20. Dotbond

    Dotbond Africa, Africa

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    Regarding the waterpump, I take it the seal is #5 in the picture??
    0760152472 Water Pump Shaft Seal Ring.
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    #20