[Loffer]

thats looks sheared from a bolt I agree, it has a curved groove cut in it. Usually you hear some initial grinding when a bolt starts to back out. Had it happen on a v-twin sprotor, red locktited the sprocket bolts and never happened again with mucho miles and 130hp to the wheel. Its usually an assembly related problem and not the failure of the sprotors themselves.

 

[Loffer]

Mine only came loose on shakedown run after mochup ( no loctite). After full assembly it never did again. 130hp, 130mph and at least 6k or so.. The bike was run on the dragstrip a couple times. Every bolt was still locked in place under inspection before I sold it a couple months ago. Just to be fair, i replaced the button heads with 5 point grade 8 fasteners with crush washers ,red loctite. anything can be made to stay in place. Saftey wire even ???

 

[Loffer]

Glad your ok man. We all have opinions