I think what is happening is 1st like everyone says you're too tight. 2nd your not turning the clevis on the wire when you tighten, you're twisting the wire. easy to fix use needle nose or slip joint pliers to grap the unthreaded end where the clevis threads on to the wire. Now tighten the clevis and don't let the wire turn inside the pliers.
Look inside the fuselage to make sure you haven't caused the wire to untwist.