Yeah Jeff, while it doesn't happen every day, it's a fairly common thing with old DID or Akront rims. I was working in the shed on Sunday arvo and I heard a ringing like two rims hitting together. Thinking it was the cat rummaging through my rim stash I didn't worry about it. A couple of weeks later I was going through them and found an XL Honda DID front rim split and seperate just like yours. There's a thread elsewhere on here (Alison?) describing others experiences with split rims.