for different cycles, e.g. convertible from two-stroke to four stroke

Internal-combustion engines convertible into other combustion-engine type, not provided for in group; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types > for different cycles, e.g. convertible from two-stroke to four-stroke

Internal-combustion engines convertible into other combustion-engine type, not provided for in F02B11/00; Internal-combustion engines of different types characterised by constructions facilitating use of same main engine-parts in different types > for different cycles, e.g. convertible from two-stroke to four stroke