The scooter piston ring Placement on the piston is crucial to proper compression and oil distribution.  If there is any writing on the rings, that is the top side of ring.  The top ring if it has writing usually will have a 1 and or a single letter.  The top ring is usually polished as well. The second ring if it has writing will usually have 2 and or a letter or pair of letters.  The Oil Ring has the expanding ring on the inside with the 2 thin side rings on the top and bottom of the expanding ring. 

Pay close attention to the gap placement in reference to the other rings.  The Mercede's Benz Logo helps to remind of their 120 degree rotational offsets.