Im making a animation and i woud like to paste the rotation of a bone from one keyframe to another. But the problem is that i also paste the location of it. I tried locking the transform but it still didnt work.
If we assume you are not using automatic keyframe insertion, you can copy keyframe and paste as stated in your question.
Next only insert keyframe rotation. The menu i show choices for selective keyframe insertion. You can move the frame cursor back and forth to confirm you have only set a keyframe for rotation, not location.