Unfortunately, this is a very bad thing. The long bolt goes way past the cylinder head, and it threads into the cylinder. The pressure oil supply to the head surrounds this bolt - and no oil will go to the head until the bolt is held in tightly. This oil galley also prevents you from drilling and tapping any new threads.
You potentially could get lucky if you take a threaded 6mm rod, and taper the threads and cut a groove across a few threads.....so that the threaded rod can maybe cut some new threads. Insert the rod into the hole and see if it starts in a few threads that may remain....and continue turning lightly until it stops turning. Mark the top of the rod about 1/4" above the top of the head cover - then remove the threaded rod and cut it off where you marked it. Then get a long 6mm nut....the kind they use to attach threaded rods together.....and put it on the top end of the threaded rod, then insert a 6mm bolt in the top of the long nut until it bottoms out against the threaded rod. Then insert the shaped end of the threaded rod into the hole, and begin turning....then you feel the rod bottom out, tap the top with a hammer, then screw the threaded rod in a bit more, then tap again and wrench again - repeat until you are afraid to tighten the nut any additional (that part is going to take some educated judgement). Then remove the bolt at the top, remove the long nut, install the special rubber sealing washer with a bit of RTV sealant on both sides. Then put some RTV sealant on the threads, and snug down a nut. Don't overtighten it, as you don't have much threads holding.
(If you need me to.....I can make the pieces you need to get this done, as I have done one for another member. Unfortunately he had his bike all torn down for painting and I never got to see it in action).
If this doesn't work - your next step is to take the engine apart....and do this:
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1448209911/0#0