Has anyone used one on this bike? Our local track had open practice last sunday, and I was getting a good bit of wheelspin. We have a int-soft terrain track, so it was actually good. It just seemed to hit so hard, like the flywheel was light. Or that my arms are not strong enough yet. What a beast. I was just wondering if anyone had tried one, and if so, what size weight woiuld be good to add. I tried a 7 oz. weight on an older KX and I couldn't really tell it was there.