Yes you can reuse the O rings, thats the nice nice nice thing about havin them! Unless they get tore up for some reason. And yeah you should just retorque back to 20-25 lbs.

i was told 18 ft lbs for a o ring head

I just recently picked up a motor supposedly built by Q. It has a O ringed head. The motor has not been started since being built. I removed the head to check the piston size. My quuestion is can I reuse the orings and is the tourqe rating still 20-25 ft lbs as stock?suzukiquadracerhq

25ft-lbs is too much for an 8mm stud whether it is o-ringed or for the engines that use a conventional head gasket.  Any thing over 20 ft lbs stresses the fragile threads in the aluminum casting.  Anything over 20 ft-lbs also distortes the bore.  Do not drive thumb tacks with a sledge hammer.  More torque is not the solution to stopping leaking head gaskets. 

Look at the bore on an engine that has been run a while and has had the monster 10mm and 3/8" studs and was torqued to 25 to 30 ft-lbs.  You will usually see 6 or 7 (number of studs) verticle shinny streaks and brown or golden color on the cylinder wall between the shinny streaks.  The shinny streaks are where the rings are touching the cylinder wall and the golden areas are where the rings are leaking.

Well I finally got to run the motor and it has a tiny antifreeze leak at the front of the head. Will have to pull the head and change the O rings. only torqued it ti 20lbs. Now if i could just fiqure out who built the motor. It has a 88mm piston, welded ears, ported , o ringed and squish set. Who ever built it used some kind of dark red sealer at the intake, powervalve cover and crankcases. I kind of doubt it is a Q motor cause the left crank case has been welded up around the shift shaft and sprocket shaft. And there is no etching on the cylinder. Now if the weather would just turn cold I could finally break this thing in on the ice

The studs are wet on the o-ring heads.  It will leak coolant around the head bolt nuts if acorn nuts and copper washers are not used  .................  or use a dap of silicone on both sides of the washers, threads and nuts.