wildcard

I just wanted to ask a couple questions. What is the diameter on the handle bars for the 82 xj 750 seca? i tried a 1 inch bar and a 7/8 inch bar. The 1 inch bar is too big. the 7/8 inch bar is ok for the risers, but the throttle and control boxes wont tighten down. Its got me baffled. I am trying to put a set of drag bars on it. Another question....is there a way to widen the back tire without messing up the drive shaft ailgnment??? Thanks, wildcard