Join Date: Jul 2008
Location: Lynnwood, WA, USA
Sorry, but I did not misinterpret.
This older style of locking the sprocket is great for maintenance and quick changes, but not so good for longevity. There is very little inboard / outboard play in the as-new setup. Play is introduced as the retainer and shaft eat into each other, esp when the retainer is badly worn as can be seen as steps in the original pic. The 2004+ STs have the more standard, high torque nut to lock down the sprocket laterally. Inboard / outboard play is not a good thing for wear, this is not a slip joint.
Ancient nascar rear differentials have little to do with our application.
A supplementary keeper with the depth that holds the sprocket in place laterally will, however minimally, reduce wear. Given the amount of wear in the OP, something is needed or a total rebuild will be needed.
Have a good one.
2001 ST4 - Thumper
2013 Ural GearUp (sold)