Thanks James..to be honest, I thought that it broke a shaft, but it turns out that the screw holding the piston on had backed out. It was weird, I had a 'feeling' that something felt funny while I was racing because my truggy was behaving really funny at times but I couldn't figure out why. I only noticed it after the race was over when I went to dust it off lol. I love this CRE Bonito engine, the power is outstanding, and it's not even close to it's full potential yet..I can't wait.