In typical ATV fashion, it was worn to hell. Measured from 86.50mm at the bottom to 86.15mm aboot mid way up, the narrowed to 86.55 at the top.
One I did tonight needed a whole mm to clean up because of the rust in it. It was so bad, I bead blasted the bore before I hogged it out. It came off a KVF650 V-Twin, the other cylinder was within .01mm of 86.50 all the way down. It didn't have water sitting in it for months and months.
This is the second one I've found in the last week. Something must scare the byrd off before it eats it. It's aboot a foot long. I tossed it in the pond a the big turtle clamped onto it, took off with it and swam around with it. Probably ate it.