Not to revive a dead thead but same thing just happened with mine. It was torqued to specs as the instructions say. I thought everything was good. My bike started first kick with no issues. After warming up I did the usual with adjusting the ignition and carbs. About 6 minutes into it the nut just fell off and the bike cut out. I ordered another one at $42 plus shipping. I was so careful not to over tighten it by using my snap-on digital 1/4 torque wrench "which is brand new" and it only got to 5 ft lbs before snapping off. Now I am too in the search for and genuine yamaha one. This is rediculous.