From:Leroy Lange Electronic:twostrokers -A-
Subject:RE: 62 hummer handle bar not tightening up ? Date:Wed Oct 5 21:58:52 2011
Response to:16409
Let me figure this out, hmm,ok, got it.
Your tripple tree has a 3/16" pin inside going left to right, your bars should have a slot going left to right also. The bars should go in 2",(measured from the bottom up)to slide over the pin inside to prevent turning. Now this is a stock application not knowing what you have for handlebars.

ive got a 62 hummer bought a replacement handle wont tighten up when i tighten top nut. bar still moves in the socket and info appreciated ..thanks