Got a great deal on these bar end mirrors for only 15 bucks each.
The mirrors and arms are decent quality, but boy did they skimp on the inside bar clamp.
I was skeptical at first if they'd hold but installed them anyway to see. They didn't hold very well. The steel is so soft that the nut just grooved it's way right down never really tightening up inside the bar. One of the mirrors flopped back at me fast on the freeway. That's not good.
So I grabbed some 3/4" conduit which fits smoothly inside the handle bar. Made an angular slice and then another straight one to end up with the two pieces shown. I just happened to have a couple of flange nuts that fit the bolt and the flange just happened to be 3/4"... perfect. If you don't have a flange nut a standard lock washer with the provided nut will work just as well.
With the assembly loose just wiggle it into the bar to where you want it. You can also leave it hanging out a little so it doesn't interfere with the throttle. Tighten it up and it will clamp on strong!
And they come back off just as easily!