Replace Rear Wheel Bolt?

I was replacing my rear sprocket yesterday on my 85 KZ1000P everything came off okay but going back on is the problem one of the bolt studs just spins around and around so I can't tighten it upm it's just finger tight.

What do I have to do to get this thing tight?

on my 78 the back of the stud is square and fits into a slot to hold it while you tighten it, maybe it is spinning? If the slot is actually broken I'd just try to jam something in there to hold it enough to get it to bite (screwdriver maybe) so you can torque it the rest of the way. Unless your bike it totally different anyway. Make sure it is firmly seated, IE you can see the same amount of thread on that stud as the rest of them. Sometimes they miss the hole and you have to push it into place from the back. Not sure if the design changed on your bike and they really are studs pressed in place and not bolts like mine. If that's the case you might just try an impact gun or something and see if it will take a bite after a minute or so.

I assume you are talking about disassembling the rear hub to see the bolt heads?

yep,pull the sprocket holder off and flip it over;)