What Happened to my Clutches?

Frostbite

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I was riding and everything worked fine. I was pulling 8,250 while climbing and and I thought all was well until I did my post ride inspection and looked at my clutches. At first I thought I was seeing water droplets still on my clutches but after a while I realized they were little chips out of my clutch faces. I bought a replacement primary clutch but, I think my secondary may be salvageable?

My question to you is, I have been riding for many decades and I have never seen anything like this before. What would have caused this? I did add a vent in front of my clutches. Could it have been ice? I can't imagine ice being able to do this to a clutch face.
 

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line8

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Do you have a phantom bolt in your brake rotor area?
I had one work out of my frame and drop down there a few weeks back. Luckily I found it before this happened. I did get a couple dimples like that, but nearly as pronounced. I found the bolt in that little area below the rotor.


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Frostbite

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Thanks line8, I didn't think so and found no evidence of what was left of a bolt in the clutch area.

I agree, it sure looks like it must have been a bolt or a nut but, why did it then stick with the belt and travel up and down the clutch faces? The belt looks fine as well.

Very perplexing!
 

line8

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I did have a couple long cut marks on the top of my belt. I kept running it and it did go on the next ride


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kiliki

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you have a piece of metal debris in the belly pan. I have seen the stem inside the back half rivet come out or lose it when you pull it.
 

Frostbite

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That makes sense and I suppose that could be true. It just seems that if a piece of metal got trapped between the belt and the clutch sheaves (which would be the only reason it could damage the entire clutch face up and down) wouldn't there be scape marks up and down the clutch faces?

These appear to be individual dings that seem to have come from perpendicular to the clutch faces.

Strange. It may still be functional but, I don't dare run it.

I think I may give the secondary a try though because it's not damaged nearly as badly.
 

line8

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Are there marks on your belt indicating anything? Like maybe it wedged itself into the side of the belt? Or in the valleys of it somehow? When you zoom on the pic, there are straight lighter type scratches, but you are right those are some aggressive holes.



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Frostbite

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The strange thing is, the belt looks perfect. Either the 0627-083 belts are pretty dang tough or for some reason the belt just wasn't damaged. Strange any way you look like it.
 

Storskogen

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Have you checked the bolts behind the driven clutch? On the non-Bigfin clutch they could break. Had a friend with similar cuts in the primary due to that.

M800 -13, Speedwerx full exhaust, PCV. BC WT 660T -06
 

Frostbite

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No, I haven't looked at those bolts but, I will today. Thanks for the idea.

I think I will save the primary for parts but install a new one. I am thinking of buying a used secondary and swapping out the sheaves as well.

I just hope whatever it is doesn't happen again with a new primary.
 

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jim

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Only takes a few seconds at 8250rpm to make a lot of marks. Very likely you have a partial piece of metal that stuck into the belt and made it around a few hundred times...or a few seconds.

The most common thing I've seen is a broken spring end (hook) getting in there and doing that.

This is why I regularly pull my belly pan and check for metal or debris...seems like there is always something in there.

As for the primary, you can machine the faces a bit and re-shim...same with the secondary. And some out there believe there is a better angle anyway...I think Racin Station will machine the faces. Could optimize your belt to clutch face angle and save the clutches.

Secondary...I'd clean up with scotch brite a bit and keep an eye out or cracks.
 

sno*jet

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you have clutch mites. open up the secondary and you should find their nest. find the queen and kill her, then they will abandon the nest and find a different sled.
some folks have used spiders to hunt the queen. that works too. :spider:
 
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