You might check with a string line and check the distances diagionally to a common point, loosen the triple trees and twist it back in line if it still doesnt steer straight check the triple clamps that they are not bent, a mate with a Golwing had a simalar problem and that is where I started looking and in his case it was the lower triple clamp bent and a very slight bend in the fork at the triple clamp. lots of measuring and straight edge work, good luck. hope it helps