To remove the piston rings, gently expand the ends of the top piston ring away from the piston and insert three or four thin metal strips between the ring and the piston, sliding these round behind the ring until it is possible to slide the ring upwards over the piston crown. Take care not to spring the rings any more than is necessary to put the strips into place and to raise them out of the grooves as piston rings are rather brittle. This applies particularly to the slotted oil control ring. Some early engines have "stepped" section scraper rings in the third groove from the top and in a groove at the bottom of the skirt.
The current type of piston is of the "Slipper" pattern and carries two compression rings and a slotted oil control ring.