KTM 60 kick starter spline.

Just trying to get some ideas on how to take a bit of giggle out of the kick starter on the external spline. The bolt only holds the lever on the spline. It does not clamp it like a gear lever does. Someone has tried a high tensile bolt before but this takes all the weight of the movement and has broken. I have had issues like this with my 426 and I fixed it by only running higher quality gear levers like hammer head. The spline is not too bad so the fix will not have to be too drastic. Thanks in advance.