if the rings are upside down on a banshee, are they not able to be compressed fully/properly into the ring groove? i know some sleds are like this. if that is the case, maybe that is this guys problem? for proper ring orientation, you need to look for a little letter marking, very near the ring end gap. the side w/the marking should face up. hope this helps. maybe you do have the wrong piston size? did you measure the outside diameter of the piston and the inside diameter of the cylinder bore, to see if something obvious sends up a red flag?