same happened to me ! I tapped holes to 1/4-20 and went to menards and found some allen head (socket head) type bolts , my stud had broke flush into the motor and just used a 3/32 drill bit to drill a hole and a easy out to remove stud! , since then I have'nt had a problem!
You boys using a torque wrench when messing with the nuts/studs that hold the head on?
i too have just fallen to the dreaded broken stud. Was on my way to the auto parts store to get some 2 stroke oil when something hit my leg and the motor was vibrating like mad. I stopped to inspect and sure enough the stud has broken. i limped the bike back to the house at 10kph and then i took the engine loose and the spacer off to find i am one of the lucky ones and there was some threads showing so i was able to back the broken piece out with some pliers. I will be off to get new hardware tomorrow. Figures it would break on me it was the last OEM bolts on the bike and it is going up for sale tomorrow.