YZ426F Clutch issue - steel thickness

I've been doing my reading and have seen people mention that the clutch steel thickness is the same across all years of the YZ426. Is this true? I needed to replace my steels (the friction plates measure within spec) so I ordered the Wiseco WPPS021 which is what is listed for the YZ (mine is a 2001). Went through a million monkey motions trying to get everything to work right (and got a new cable) with no luck. As a matter of fact, one of the friction plates wouldn't fit back in to the stack!

Anyway, I pulled the new steels out and compared them to the old ones. The new stack is nearly twice as thick as the old with the new steels measuring about .065 inch and the old measuring about .043 each. That ain't right! I know things wear, but it should be the friction plates that do most of the wearing, not the steels. Has anybody run into this issue before? Am I not searching the right thing....point me out a thread if not.



2001 YZ426 plate thicknesses are listed as 1.1-1.3mm (.043-.051") for the steels and 2.9-3.1mm (.114-.122") for the frictions. .065" is too thick, and will result in the clutch stack being .112" too thick. I would use OEM Yamaha plates, or at least replace the steels in the set with genuine Yamaha part number 5JG-16325-00-00 (eight required).

The steel plates were the same for all 3 production years of the 426. The Wiseco plates are the wrong dimension.


That's what I suspected. Wiseco is working on figuring out if they mis-packaged some items.


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