You mean the screw in thingy that goes into the right fork leg? (4 of them?) If you can get a grip on it with some mole-grips get it out and take it to a nuts/bolts/ screw shop for a replacement Short of that get a bar the same radius and desired length and then die the threads into it.. While you're making 1 make another few, they're prone to failure
Ahh they're also prone to failure, just tend to corrode and kinda fall to pieces.. I took one of my old YZ 250 and it was a perfect fit (probably the only thing that is interchangable between the 2 bikes)