1990 K75 RT Mirror Repair

Six years ago on the second day I owned this bike I "dropped" it. More like a slow settling at a stop. At any rate the mirror broke away but the back of the mirror shell separated from the front. It looks as though it must have been glued at the factory. If so, what did they glue it with? The material looks to be ABS so I tried some ABS glue but it didn't hold. Any suggestions as to what glue will give a good hold?

Also how would one go about clamping the whole works together since there are no flat or parallel surfaces?

I've done this to both mirrors on my K75 Rt; Broken open the mirror half's
Get some plastic compatible epoxy and glue the halves together and hold them tight with rubber bands.
Easy fix

Forgot what I used, but putting it back together is doable.

Maybe check with a body shop for a suggestion for the best glue.

I checked with body shop and they recommended two things. Use a couple of spots of urethane windshield adhesive between the inner and outer shells to provide some vibration resistance. There is very small surface that bonds the two shells together so this is belts and braces approach. Then apply some CAA adhesive to the edges where the original bond took place. The recommended adhesive is s slow set until an accelerator is applied. This gives time to wrap tape around the halves and line everything up. Then spray the accelerator on it and let everything sit for a day to allow the urethane to set up. I'll see how well it works.