Main Group 1 - Engine, Clutch, Cooling, Fuel/Air

00 - Engine
01 - Crankcase
99 - Engine to transmission securing parts
01 - Cylinders, Cylinder head
05 - Crankshaft, Connecting rods, Crankshaft bearings
07 - Piston, Piston rings
09 - Camshaft, Valves
15 - Oil pump
15 - Oil filler
17 - Oil cooler
19 - Air cooling
19 - Cooling air control
19 - Engine cover plates
27 - Fuel pump
27 - Fuel lines
29 - Carburetors
29 - Air cleaners
29 - Intake manifold and intake pipe
31 - Exhaust Control System
41 - Clutch 
98 - Repair kits