Hi,
I'm new too. There's an old bodge which might sort your problem out for a while. What you need to do is remove the bolt from the kickstart lever. Get some sewing needles or pins (needles are best as they are harder material) With the lever positioned where you want it; stick a flat bladed screwdriver in the gap, that the bolt would close up if overtightened, and slightly splay this gap which will loosen the lever even further on the spline. With the lever in the position you want, force the pins in between the lever and the shaft. You may only get a couple in but these will take up the slack. Put your bolt back in and tighten up. Try and snap the excess ends of the needles off with a twist of the pliers. This should do the business but no guarantees.