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Discussion Starter · #1 ·
My '02 XC 500 SP revs to 8600 or 8700 rpm at WOT. But it seems to have lost some top-end speed. If I hold WOT, it will pull that higher rpm all the way to top speed. But, if I hold partial throttle, to keep it at, say 8200 rpm, it will top out around 60 to 80 mph, depending on snow conditions.

So, I think I have a problem with the clutches. What is a likely cause?
 

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sounds like a clutch binding problem.
 

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Discussion Starter · #4 ·
ripperd said:
Huh? So you don't hold full throttle, and it doesn't wind out all the way, or go as fast? Sounds pretty normal to me...
No, if I DON'T hold full throttle, it DOES wind out all the way--8200 rpm. But it won't pull higher speeds. If I hold WOT, it over-revs by 400 to 500 rpm, and still doesn't have the top end speed it used to. On long runs on hard-pack, I used to see 100 mph on the speedo. Now, 90 mph is about the end of it.




madcow said:
sounds like a clutch binding problem.
Would it be binding on the primary or the secondary?
 

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Sounds like the primary is not fully closing.
 

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thats for you to find out.

remove primary, take out spring and see how the sheave moves.
take apart secondary and inspect helix/buttons.
 

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Discussion Starter · #9 ·
Yeah, sorry, after re-reading my post, it wasn't very clear.

Yes, my target rpm is 8200.

I'll start by taking the clutches apart.

But, it doesn't sound like a weak spring to anybody?
 

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bad spring would have your rpms way low.
 

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Discussion Starter · #11 ·
I took apart and cleaned the secondary clutch. It was a little gummy inside, but not bad. The buttons are a little worn, but don't seem too bad.

But, the primary clutch is a different story. I found a little rust on the chrome shaft between the two sheaves.

Auto part Pipe Rim Steel Wheel



And some pitting on the black shaft where the outer sheave slides.

Auto part Tire Wheel Rim Alloy wheel



The outer sheave does not slide completely freely. Can I use some emery cloth on the pitting on the black part of the shaft? Or, even a file? On the chrome part, I don't think I'd want to use that, but maybe some fine steel wool. What suggestions does anybody have?
 

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you can try some emery cloth.
 
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