Help! KZ750 Cylinder bolt

I’m rebuilding a 1982 KZ750 and was putting in the head bolts. They seem to be streatching and not getting to torque spec which is 22 foot pounds. So I bought some normal shank bolts and threaded one in. I torqued them down the all of a sudden one bolt went loose. So I pulled the head and I have stripped the threads in the cylinder head. Now I’m really mad and frustrated. Are these bolts supposed to pull/stretch? Or should I go with the shank bolt?

I know that I’ll need to tap it and rethread it with a helicoil. But should I just try the shank bolts on them again?


I really need help. This is very frustrating cuz IDK what to do.


Thanks.

Those are special bolts designed to stretch more than a normal bolt, that's why the shank is necked down. I strongly recommend replacing them with new OEM parts during the rebuild. When torquing, I found on my rebuild that they will not tolerate the full 22 ft-lbs before starting to stretch. I stopped tightening at about 20 or so, when I could feel that they were not going to tighten any further.