12 point head bolt, rear jug left front side, bike sounded like a beast, pull over and see a missing bolt, idles fine but under load a warm left thigh and sounding like a beast, where is the bolt and how is it gone...thought I might measure the depth of the hole to see if maybe part of the bolt is in the hole, hoping a retorqued new 12 point will fix, so the head gasket is not blown out right, that's a question. Any thoughts very much appreciated, thanks for reading.
RE: 95 EVO 1340 stock

 

My dad had a case stud pull on his Evo, then the Timesert pulled a few miles later just like your issue.

Then as a hail Mary we used a big-*** threaded insert from McMaster Carr. It's a 9/16"-12 outer thread, much larger than a Timesert or Helicoil so you'd have a lot more surface area objecting the forces from the head bolt. It was kinda hard to tap such a large hole but he took his time and did it as perpendicular as possible.

Low and behold, that was a few thousand miles ago.