[roostafish]

Alright, my head has been removed from my nether regions, and here's the scoop.

The Yamaha kickstarter is shallower on the splines, ever so slightly than the Gas Gas. It fits fine, but there is a microscopic amount of play, which got looser over time, and was causing my problem. What I did to fix it was to fill the gap between the back side of the starter, and the raised boss on the shaft. I happened to have a copper washer in my junk drawer, and I drilled it out to fit. It is now acting as a shim, and it should fix the problem permanently. Thanks for the replies. At least it gave me an excuse to post here!