Yepper.. the back one on the right side broke today. (more issues with trying to remove that engine guard) MY stud seemed to be turning with the nut.. maybe i'm nuts but it felt that way. Mine broke right at the cap nut, so with the header and flange off, you can still grab the stud. Whats the easiest way to get that out and put in a new one. In the meantime, i assume there is no problem with running the bike. The other cap nut on that side is plenty snug
BTW.. all other issues seem to be resolved and Franco is running great.. topped 100mph just to say i did
The good news is that you still have a substancial portion of the stud to grab onto.
I suggest spraying the stud joint with your favorite penetrating oil (PB Blaster or whatever) 2 or 3 times during the day, and let it sit for a few hours or even overnight.
Grip the exposed remaining stud firmly with a pair of Vice Grips with good teeth.
Beginning gently, slowly twist the stud back and forth to break the corrosion seal. Don`t break the stud again!!
Alternate firm raps with a hammer on the stud with further twisting.
Judicious application of heat with a propane torch may help as well.
Just don`t put too much heat into the aluminum block.
Go slow and easy. The expression "worry it off" comes to mind here.
When you get it out, clean the blind hole threads with the appropriate sized thread tap.
Keep it lubricated with squirts of penetrating oil as you turn the tap in a bit and feel resistance.
Stop, back tap out, clean crud off with spray or small brush and repeat unil you get to the bottom of the hole.
Prior to installing a new stud, apply a bit of CopperCote or other anti-seize coating to the threads.
On the upper end of the stud, screw on two nuts and using two wrenches tighten against each other to lock them together. You now have a place to use a wrench to tighten the stud in the hole. Use the two wrenches again to unlock the nuts and remove from stud.
You can also use an ordinary cap screw (bolt) instead of a stud and nut, if you are not concerned about not having a shiny chrome acorn nut in that place.
Stainless steel might be a better choice if you go this route.