Looking at buying a 2002 mxz 700. It has 3000 miles on it. Very clean machine but one cylinder is at 60 lbs and the sled sat for a while with old gas in it. Would bad gas cause a problem with the piston or rings. And what would a worst case scenario cost be to replace jug, piston, rings etc. He is offering the sled at a fairly good price. Any help would be appreciated.