I found some lock washers that are the right size to take up the slack, but you would need a stack of them, and it wouldn't protect the case at all.
Heat and sometimes lack of fluid make it lock up. Sometimes revving before and while you stop can break it out, but not always, and if you gots more power- that's really not going to work.
The really frustrating part is that sachs still makes clutches for all kinds of cars, and motorcycles- who was asleep when they designed these things?