From A Garage Kept 99 Ski-Doo Formula 3 600 with 3500 miles.  Crank shaft was rebuilt and pistons changed 400 miles before teardown. Compression on #1 was 130#. There is some scratching lines in cylinder but you cannot feel any of them with finger or finger nail. The cylinder and piston are matching set. This was a good running engine until CDI went out. I cleaned top of piston. The piston looked like #3 in last picture when taken out. Comes with bearing and pin. I will pack with piston lubed and inside cylinder. Boxed securely.