to the OP: If the ZX7 gets head-shake and leaks coolant, as a fellow track rider, I wouldn't want it anywhere near me, or the track on which i'm riding. Your personal safety is one issue. I'd encourage you to make smart choices there, but leaking fluids on the track or riding a bike that you aren't sure is safe (sounds like you might have tweaked forks) is unsafe for those around you as well. If that's what it comes down to, ride the ZX10, or drop some cash and make sure the ZX7 is in proper working order. And yeah, crashing is always a possibility, but I wouldn't call it "common." On a bad day at the track, you'll see 10 crashes. Consider that you've probably got 100+ people riding, and you're looking at a 90% chance that you WON'T crash. Ultimately, you control your pace. Ride within your limits, and your odds of crashing drop drastically.