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So I heard a knock..

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I heard a knocking in a race this weekend and assumed it was the crank.  It was so severe I felt it in my feet.

I pulled the top end and cannot find anything loose.  The flywheel has no motion, and connecting rod and piston have no vertical play.  Could this still be the crank, or did I possibly pull it apart prematurely and should be looking elsewhere?

The bike is a 2007 200xc.

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I heard a knocking in a race this weekend and assumed it was the crank.  It was so severe I felt it in my feet.
I pulled the top end and cannot find anything loose.  The flywheel has no motion, and connecting rod and piston have no vertical play.  Could this still be the crank, or did I possibly pull it apart prematurely and should be looking elsewhere?
The bike is a 2007 200xc.

ive had mine rarely make a noise like that maybe power valve linkage im not sure

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I should have given more detail, this was only at low RPM, kind of lugging conditions.  The bike continued to rev out great, starts and idles fine, etc.  

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Did the noise go away when holding the clutch? My guess would also be the clutch if the topend and crank rod looked good.

Edited by Cartoscro

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If it's knocking while accelerating or on the throttle and sounds like there are rocks banging in your engine it is most likely detonation. You can richer up whatever circuit you are feeling the knock at 1/8-1/2 pilot, 1/2-3/4 needle, 1/2-wot main jet. The needle will overlap with pilot and main jet but handles mid throttle settings. This should do the trick another thing that helps is adding a splash of race fuel if you have it but the jetting should clear it up.

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Was it doing it while you were lugging the bike in a higher gear than usual? I suspect that the sound you were hearing is chain slap. How are your slider and guide?

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It seems like this has developed further so that now a hard stab of the rear brake is causing seemingly the same thing.  Engine mounting is tight.  Clutch basket?

On 9/24/2017 at 5:57 PM, orangyktmthing said:

Was it doing it while you were lugging the bike in a higher gear than usual? I suspect that the sound you were hearing is chain slap. How are your slider and guide?

This could be, I was considering rolling it around the yard and stabbing the brake without the chain, but this wouldn't isolate chain slap from clutch basket.

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you should only be to fit 3-4 fingers vertically between the top of the swingarm (where the rubber guide ends) and the chain with the rear wheel elevated.

I doubt it has anything to do with the PV. I Have had the control arm gears strip out and i didn't even notice it. That design is pretty robust.

I think something in your chassis is moving around:

Steering head

shock bolts.

swing arm bearings could have play.

One of the wheel hubs (more likely the rear)  could have play.

Edited by 2strokezuke

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Everything is checking out, and I don't know why I didn't pull the clutch cover before.... but.. I take it this isn't correct.  Any idea if this is my basket worn or my clutch plates?  I have spare plates from my 250, before I take it down, these are different.  Correct?

 

 

 

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My older ktms had steel clutch baskets stock. They lasted forever but were very noisy and loose fitting. . They rang like a tuning fork at idle. 

 

 Im having trouble replaying your vid. Is it steel? 

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Yes it's steel.  The plates appear to be alluminum.   I run ATF, could this be a bad combination?  Change to another oil and revisit?  

Screenshot_20171005-060906.png

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 Many run aluminium but i much prefer steel. The oil stays much cleaner. 

 

 I prefer AFT too.  

Edited by seer

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