Is it cooked?

4 replies to this topic
  • cjard

Posted April 11, 2010 - 11:53 AM


My '02 YZ426F clutch was slipping a bit, so I pulled it out..

Posted Image
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Can it be repaired, or is a replacement required?

  • brentn

Posted April 11, 2010 - 12:07 PM


the steel plates have been heated up quite a bit from slippage, they may now be warped. Use a flat plate to find out with some shims, however they may be so bad that you'll be able to see how warped they are just by eyeballing it. The friction plates look thin but a side shot is needed to tell, they may be warped as well from the heat.
my guess is an incorrectly set perch where the clutch was never fully engaged and or springs that were out of spec.

If the steel plates are warped they should be replaced or else you'll get grabbing with new fiber plates installed and/or more excessive clutch wear.

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  • cjard

Posted April 13, 2010 - 03:12 AM


Friction material is good, no discernible warping.
Ive cleaned the plates up and come to re fit them (what the heck, if it doesn't work it's not like I've lost anything) and I have a question..

The bike is leaned on its side and I'm looking at the clutch boss, and I can see 2 things I didnt notice before - 2 metal rings of a smaller diameter than the steel plates, as the fist things on the boss. one of them is flat, like a washer, the other is slightly cone shaped

I took a look in my manual and I couldnt see any mention of anything like this to go back on the clutch.. Also my manual said that that the last friction plate to go on should be the "skinny" friction plate (the one in the above picture that is more grey coloured than black like the others)..
When I took the clutch apart, this was at the bottom (i.e. it was the firs tto go on)
It looks like these metal spacers I found fit within the skinny friction plate

Any ideas wha tthey are for?

  • matt4x4

Posted April 13, 2010 - 04:01 AM


This is how it should go back together - I think how you explained taking it apart is the correct way judging by this picture:
Posted Image

  • grayracer513

Posted April 13, 2010 - 09:54 AM


The narrow friction plate with the larger I.D. does go at the bottom of the stack in order to clear the boss spring and spring plate, which are the two very narrow bands of steel you found there.

The first item on the boss should be the spring plate, which is the flat one of the two rings. Next in is the boss spring. This thin ring appears slightly conical when viewed from the side. It works regardless of which way it's installed, but it should be a little better installed with the "small end", or "top" of the cone facing out. Then the above mentioned friction plate. The purpose of the spring is to buffer the engagement of the clutch so that it can't grab suddenly as you release the lever.

The rest of the stack goes in like any normal clutch.

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