| 123 / | HD | INTERNAL-COMBUSTION ENGINES |
| 65 R | DF | TWO-CYCLE {24} |
| * | DD | .~ Rear compression {2} |
| 73 R | DF | .~.~ Crankcase {17} |
| 73 C | ![]() | .~.~.~ Fuel to cylinder {3} |
| 73 CA | DF | .~.~.~.~> Lengthwise scavenging of cylinders from head |
| 73 CB | DF | .~.~.~.~> With liquid pump to separate inlet |
| 73 CC | DF | .~.~.~.~> With gas or vapor pump to separate |