KTM 640 Horrible engine noise!!!!

Discussion in 'Thumpers' started by moto_psycho, Feb 9, 2013.

?

What is the horrible noise?

  1. Cam chain tensioner

  2. Camshaft rockers / bearings

  3. Big end

  4. Gearbox main shaft bearing

  5. Crankshaft bearings

  6. Other?

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  1. moto_psycho

    moto_psycho Nob.

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    #1
  2. tallbob

    tallbob Been here awhile

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    Sounds louder on the left side. I'd pull the left side case cover and take a look. Just lay the bike down on a couple of tires or something and you won't have to drain the oil. Pull the clutch cover and the clutch so you can see the main shaft bearing and take a good look at the balancer and bearings.

    Make sure it's not something outside the engine vibrating. Exhaust, skid plate, kick starter etc. can vibrate and make a racket. Good luck hope it's not serious.

    Tallbob
    99 LC4E
    #2
  3. moto_psycho

    moto_psycho Nob.

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    I just pulled the right side and there is no play in the rotor.

    There seems to be an accumulation of noises... perhaps I have every common lc4 fault there is. We have people coming round to view the house in a couple hours so I can't really do anything till 2moro :(.

    There does seem to be a bit of a noise at the very front of the left side of the engine. Is that the balance shaft?
    #3
  4. Kawidad

    Kawidad Long timer

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    Is this a new noise or has it been loud?

    The LC4 engines make a lot of weird noises without being defective.

    :ear
    #4
  5. tallbob

    tallbob Been here awhile

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    If I remember right that's where the balancer is. It's been a long time since I've had mine opened up. Your bike probably has the upgraded main shaft bearing but it would be worth a look. If you haven't already, check your oil for metal debris which could mean a bearing problem.
    #5
  6. It'sNotTheBike

    It'sNotTheBike Banned

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    Quit running the bike, period. It is not going to
    fix itself by running, but it may indeed destroy itself.

    Tear the engine down, inspect and repair.
    #6
  7. It'sNotTheBike

    It'sNotTheBike Banned

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    #7
  8. gunnerbuck

    gunnerbuck Island Hopper

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    It is not the mainshaft bearing that is making that sound...

    It is likely one of the bearings on the crankshaft, it actually sounds like the left side crank end bearing is having mini seizures... I would suspect you may also have some piston damage... I would not run the engine any more and start an investigative tear down... With any luck it will be just a seized up balancer, but to me it sounds much worse...
    #8
  9. moto_psycho

    moto_psycho Nob.

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    That fills me with confidence! 1st viewing over, 1 to go, then I'll get that left cover off!
    #9
  10. RideFreak

    RideFreak Torque Junkie

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    Sounds too frequent to be the big end, I think it's in the topend.
    #10
  11. moto_psycho

    moto_psycho Nob.

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    Counter balance shaft is slapping around like a turd in a bucket. I'm gonna try removing it
    #11
  12. moto_psycho

    moto_psycho Nob.

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    Ok, I'm guessing you can't get the counterbalance off without removing the clutch basket and crank pulley?

    Crank is solid and turns nicely, same with clutch...
    #12
  13. gunnerbuck

    gunnerbuck Island Hopper

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    The counter balancer normally feels like it is overly sloppy when the clutch sidecover is off, it takes the second bearing in the cover to hold it steady...

    Yes, you must remove the clutch and gears to get the balancer off... Once removed, you'll be able to see if the balancer is all scraped up from rubbing the cases as well as the cases being scraped up themselves to indicate shot bearings...
    #13
  14. ericGSsti

    ericGSsti Been here awhile

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    My 640 adv started sounding like this today after a run in the mountains. Sounds like a bag of spaners. Dropped it up to my machanic just before closing and he did a quick stethoscope check to try and pin point and it sounds like the clutch area to. So very interested in what you discover. Could be the same thing. :cry
    #14
  15. moto_psycho

    moto_psycho Nob.

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    PayPal have locked my account until £5 clears, so hopefully mid week I will have a strap wrench to take the clutch basket off, afterwards I will take the counter shaft out and start her up again, I'll make the same video again we'll see what wee get!
    #15
  16. gunnerbuck

    gunnerbuck Island Hopper

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    What year is your bike?
    #16
  17. klxmack

    klxmack king of the box

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    Ha ha, Hold it up to the phone again! wait, it sound like opportunity knocking.

    If motor was quiet, then got loud and you have oil in the motor, then its tear down time.

    Taking a pole and getting advise is kinda silly.


    Sorry my friend, shit happens.


    Cheers
    #17
  18. gunnerbuck

    gunnerbuck Island Hopper

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    [quote
    Refer to that thread now, so far no end float in either side of crank, clutch seems fine. Counter balance outer case bearing is fine, but without removing there seems to be a lot of play on the inner bearing. Waiting for tools to arrive to remove. I have a sneaking suspicion it is the counter balance and the cam rockers.quote]

    There doesn't have to be end float on either end of the crank for the bearing to be bad, the running surface of the races only need to be galled... If you have the head/cylinder off you can spin the crank rapidly around in the case and listen for the grinding noise to indicate a rough bearing...

    As for the balancer being shot, I have a sneaking suspicion that you won't get away that easy, but one can only hope...
    #18
  19. moto_psycho

    moto_psycho Nob.

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    Turning it over by hand with the spark plug out doesnt give me any noise, atm I am suspecting counter balance and possibly cam... just waiting for strap wrench to arrive to get clutch off
    #19
  20. Dolly Sod

    Dolly Sod Red Clay Halo

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    So, what's the oil look like?
    #20