05' KTM 640 Adv Main Shaft Wobble and Clutch Noise

Discussion in 'Thumpers' started by Highjnx, Jun 21, 2013.

  1. Highjnx

    Highjnx Serious Orange Crush

    Joined:
    Jan 25, 2010
    Oddometer:
    65
    Location:
    Seattle, WA
    Bike has 21k miles. Started losing clutch fluid inside the motor on the last ride. Was also having a loud clutch noise and vibration (wobbling basket sound) until I would engage the clutch lever. Now that the drive chains off I notice the front sprocket turned to some extent in neutral, no matter if clutch lever was engaged or not. I assumed this would be a simple slave O-Ring replacement.

    In preparation for replacing the clutch slave O-Ring, I drained oil and found long metallic shavings and a fine metallic mud on the magnetic drain plugs. Cracked the clutch cover and found that I have excessive play, perpendicular to the main shaft. This is the 05' LC4 Adventure with the newer style bearings. The other side of the transmission main shaft makes a noise as heard in the video. It appears there is play in the main shaft bearing. And when moving the main shaft up and down, it almost feels like the opposite end (interior engine side) has just as much play, and it's simply teeter tottering on the main shaft bearing. I don't have enough experience with the interior end of the main shaft to say this is within tolerance.

    The Countershaft Balancer (front of engine) has an extreme amount of play, however I'm assuming this is normal as it's outer edge normally resides in a bearing on the clutch cover.

    I'm thinking there might be a badly disintegrated bearing on the inside of the case - opposite the main shaft. Transmission Countershaft Main Bearing? I haven't been able to locate any damage inside. All bearings, teeth, retainers all look good. The bike was driven 200 miles after noticing the leak and noise. It's a mystery where the metal came from.

    Questions:

    1) What does the interior end of the transmission main shaft rest on. Or does it float inside the gears. In the parts manual it looks like it just feeds through to gears on roller bearings.

    2) Does this bearing appear to be shot.

    3) Will a new transmission main shaft bearing tighten up this shaft.

    4) Do you have to split the case to replace the newer style bearings. I've read Mark's brilliant LC4 640 Main Shaft Bearing replacement How To. All 15 page which refer to the older (2002 and earlier) 640's with their riveted ball bearings.

    If anyone has some input I'm greatly appreciative. If there's a KTM mechanic that does some side work - and would like to have a crack at this, let me know, I can pull the engine.:ear

    Thanks

    Here's a Youtube video and some photos.

    http://youtu.be/BXecXvvS_aw

    [​IMG][/URL]

    [​IMG][/URL]
    #1
  2. gunnerbuck

    gunnerbuck Island Hopper

    Joined:
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    5,712
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    What your describing does not sound very good, the mainshaft should almost feel static with very little play...

    To me it sounds like the needle bearing on the slave end of the mainshaft may be toast and possibly the mainshaft roller bearing too... What usually kills the needle bearing prematurely is when contamination gets between the needles, the race and the shaft... This is sometimes caused by grit dropping in when the slave has been removed...

    The best thing to do would be to pull the engine, split the cases to guage the extent of the damage... Greydawg went through this in a big way a while back, check out his thread:http://advrider.com/forums/showthread.php?t=551527
    #2
  3. Highjnx

    Highjnx Serious Orange Crush

    Joined:
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    65
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    Seattle, WA
    Thanks Gunner,

    I hadn't seen that thread yet, and now that I have - it's seems like a probable suspect. I haven't pulled the slave yet - will do tonight.

    I was looking around on Ebay for a used motor - fearing the worse. Found a couple of LC4 Cases with bearings in them for under $400.00. It sounds like this is the logical path? Any estimate on the time it would take to swap things out. I appreciate your help...
    #3
  4. gunnerbuck

    gunnerbuck Island Hopper

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    Most of the motor cases on ebay will be pre 03 with the old cam to pushrod style clutch... There was a guy in fleamarket a while back that had most of a 03-04 motor up for sale for $600... I believe it was in Florida so a costly ship...
    #4
  5. gunnerbuck

    gunnerbuck Island Hopper

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    First you need to look inside your cases, to do this it usually takes me 3-4hrs to pull the engine and have it completely stripped apart...

    Once apart you can see if the damage has gone outside the bearing race and into the case If this has happened then you will need to replace the case, if not you can simply drive the old bearing out and replace it... It is very likely that your mainshaft will be damaged where it rides inside the bearing...

    Proper engine reassembly usually takes at least twice as long as teardown because you need to clean gasket surfaces, clean inside engine, check oil pump internals, check oil passageways, measure things to spec, apply loctite to spec and torque fasteners to spec...
    #5
  6. Highjnx

    Highjnx Serious Orange Crush

    Joined:
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    Oddometer:
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    Location:
    Seattle, WA
    Just finished pulling the clutch slave. There was some metallic paste, but overall not to bad. The piston did have some slight wear on the interior edge. But the bad part, the main shaft has about 2mm of play on that side. I'm thankful that I didn't drive this more than 200 miles and tore it down right away.

    So if I understand this. I need to pull the engine and split the case to get at this bearing?

    Thanks Gunner.

    Here's a video of the movement on the slave side and a photo of the slave.

    http://youtu.be/NszFykCKajw

    [​IMG][/URL]
    #6
  7. gunnerbuck

    gunnerbuck Island Hopper

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    Well in theory you could heat the case area around the needle bearing and try to pry it outward as the bearing can be driven both ways... The problem is that even if you get the bearing out and replaced it is likely that the shaft is also worn so the replacement bearing may not last too long...
    #7
  8. Highjnx

    Highjnx Serious Orange Crush

    Joined:
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    Location:
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    Actually looking at this again, the entire bearing assembly is spinning inside the case. I can turn it completely around.

    If that's the case, (no pun intended) :clap then pulling just the bearing doesn't seem like it's plausible - reaffirming your path on this repair. Would you mind taking a look at that video and commentating.

    Found both sets of shafts and gears from an 05' LC4 625 for less than the price of the main shaft $420.00. Do you think it's possible to have the right side case machined for a new bearing.

    I'm thinking it's time to get my 07' out this season, and save this for a rainy Winter project. We have a short season in Seattle.

    And again, thanks for your help.
    #8
  9. gunnerbuck

    gunnerbuck Island Hopper

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    In your video I only see the up and down and a bit of rotational movement of the end of the shaft... The needle bearing assembly looks still to be in the case as it should be.... If you can spin that bearing containment cage in the case then you should be able to easily pull it out of and clear of the shaft...

    Any gearbox from the late 90s on should work in your engine.... The gearboxes in these engines are tuff so the chances of purchasing a good used one are high... I've picked up a couple of spare used LC 4 gearboxes and both show little wear...
    #9