We just rebuilt my buddies 2002 MXZ500. His son had an accident with it December 2006, so it sat for the last 13+ months. Damage was mostly to plastic and a bit to suspension. Engine ran after the accident (just on and off the trailer). We repaired it this month and it wouldn't start. Compression was 30lbs. We opened it up, and the rings, pistons, and needle bearings were rusted. Everything was in good shape, but extreme rust. We replaced the needle bearings and rings (although the rings looked good), cleaned up the rest, and it runs great. Only 1300 miles on this sled.

It was stored in his garage since the accident. Ever heard of this? How do you avoid it?

use a brand of oil with rust inhibitors, sounds like maybe he didn't?

Synthetic.........will rust em out everytime