The set includes 2 liner seals, only one should be used. They are marked yellow or red. The red (5.0 mm) is used for early engines with grooves-Ø 118.54 to 118.80 mm. The yellow (4.7 mm) is used to late engines with grooves-Ø from 118.32 to 118.58 mm. The change occurred in autumn of 1979.