Anyone here lose their clutch?

[isaac_]

In the middle of a race, I go to downshift and find it out the lever pulls all the way in without any tension. I pit in and notice the clutch lever goes all the way in but the little 90 degree lever with the spring down by the engine is rotating when I pull the clutch. So that tells me the cable works and the problem is internal. Anyone experience that before?

I can manually shift through the gears if I roll the bike and tap the shifter. I just can’t use my clutch lever to disengage the clutch.

 

[green_bread]

Yep. The reverse thread nut that holds on the clutch basket has backed itself off. Happened to me during a race weekend once, as well.

Post 46 of 49 in this thread has a picture of a torque wrench on the nut that I am talking about. This is a common problem on the RC/Duke.

390 clutch failure! - Page 5 - KTM Duke 390 Forum

Edit:
Heres another pic for you! (This is not a RC 390 motor, but it looks very similar to this) The nut right in the middle, there.

 

[isaac_]

I locktited that sumbitch and drilled it with an impact gun. I’d be hard pressed to think this backed out. We’ll see what my mech tells me


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[green_bread]

Well, its something in that stack, for sure, unless you snapped the plunger, itself. Youre lacking the required tension in order to be able to compress the springs and move the clutch away from the flywheel.

 

[isaac_]

Well, its something in that stack, for sure, unless you snapped the plunger, itself. Youre lacking the required tension in order to be able to compress the springs and move the clutch away from the flywheel.

I did feel the clutch lever a bit harder to operate when I picked it up from the shop. Mech tells me he didn’t touch the clutch basket other than to remove the clutch cover to inspect it. We’ll see what he says.

 

[isaac_]

Nut backed out completely. Fudge.


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[green_bread]

Nut backed out completely. Fudge.

As expected. Its a pretty common issue on these bikes. Ive seen several threads about it posted here, which is why I always go to that as the cause of the symptoms you described. Had it not happened to me the very first weekend I raced this bike, I wouldnt have had any idea. After I took everything apart and reassembled, it becomes pretty clear as to why the plunger can no longer push the clutch away from the flywheel.

The good news is that it should be a simple fix for your mechanic, assuming nothing got stripped out (mine didnt and I ran it for at least half of a 25 min race like that), to tighten the nut back down and apply a little blue thread locker. ;-)

EDIT: Well, I see that you said you put thread locker on it, before. Damn man.. that sucks. Mine has been completely fine since I re-torqued it with a little of the blue stuff. I hope that yours stays put this time!