ORIGINAL STANDARD BORE IS 83MM, 725cc 747cc Used in CH25, CH26, CH730, CH735, CH740, CH745, CH750, CV25, CV26, CV724, CV725, CV730, CV740, CV745, CV750, LH755, LH775, SV710, SV715, SV720, SV725, SV730, SV735, SV740, SV810, SV820, SV830, SV840, ECV749 THAT REQUIRE 1.5MM THICK RINGS.