Looking for piston/rings and cylinder for the XL910.
While there may be other part numbers, the cylinder I have is stamped 63012 and I believe the piston 68033.
The IPLs show: Cylinder 63012-2 for the XL-700 and XL-901 68294 for the XL-921 Piston 63780 for the XL-700 and XL-901 This does not include the rings. 68033 for the XL-921 -This part number includes the rings. Piston rings for all these is 55038.
The pistons, except for the wrist pin retainers, are probably identical. The 700 and 901 used two different retainers where the 921 used the same retainer on both sides. There is probably some small change between the two cylinders too. Could be something with the ports or maybe the muffler bolt holes. Anytime something changed, either with the design or with the packaging, a new part number was assigned.