I had this real clean 650sx pump from my old JetJon, (man I miss that thing) but I had to cut the ears off so it would mate up to the pump tunnel I was using. It has been sitting in a tub for the last 2 years. The wear ring was like new but practically useless for anything else so I never tossed it.
The wear ring in the pump I got on that 650 hull was pretty swelled.
Sooooo I swapped them.
Easy as pie! Only took like an hour.
I put the ring in the freezer and the pump in the oven. A couple of taps and it slid right in. Set screw even lined up