We are working on a 81 cb750c and after rebuilding carbs and fixing all other mechanical items, after starting we noticed oil accumulating on fins of the front of the cylinder jugs. When checking things out we noticed that the 2nd stud from the crankcase spins with finger pressure from outside of the block, but when removing valve cover the same stud that enters into camshaft head does not move when the stud is spun from the outside. We think that the jug may not be fully or evenly tightened and allowing some oil to leak at gasket area when engine is running. Is there some type of sleeve over the outside of that stud between the crank and cam head or is that the actual stud, if so, why does it move under finger pressure but the final threaded section of stud in camshaft head does not appear to move also? Can this stud be tightened down from camshaft head or will head and jugs need to be pulled to fix at crankshaft block?