(subclass TwoCylinderEngine IntermittentCombustionEngine) | Cars.kif 4540-4540 | Two cylinder engine is a subclass of intermittent combustion engine |
(subclass HarleyDavidsonKnuckleheadEngine TwoCylinderEngine) | Cars.kif 4578-4578 | Knucklehead is a subclass of two cylinder engine |
(subclass HarleyDavidsonPanheadEngine TwoCylinderEngine) | Cars.kif 4682-4682 | Panhead is a subclass of two cylinder engine |