CONTENTS
Section Title Page
1. SPECIFICATIONS....................................................................................................... 1
2. PERFORMANCE ........................................................................................................3
2-1 MAXIMUM OUTPUT........................................................................................................ 3
2-2 CONTINUOUS RATED OUTPUT .................................................................................... 3
2-3 MAXIMUM TORQUE ....................................................................................................... 3
2-4 PERFORMANCE CURVES ............................................................................................. 4
3. FEATURES..................................................................................................................6
4. GENERAL DESCRIPTION OF ENGINE COMPONENTS .......................................... 7
4-1 CYLINDER AND CRANKCASE ....................................................................................... 7
4-2 MAIN BEARING COVER ................................................................................................. 7
4-3 CRANKSHAFT.................................................................................................................7
4-4 CONNECTING ROD AND PISTON ................................................................................. 8
4-5 PISTON RINGS ...............................................................................................................8
4-6 CAMSHAFT ..................................................................................................................... 8
4-7 VALVE ARRANGEMENT ................................................................................................. 9
4-8 CYLINDER HEAD............................................................................................................ 9
4-9 GOVERNOR SYSTEM .................................................................................................... 9
4-10 COOLING SYSTEM..................................................................................................... 10
4-11 LUBRICATION SYSTEM.............................................................................................. 10
4-12 IGNITION SYSTEM ..................................................................................................... 10
4-13 CARBURETOR............................................................................................................ 10
4-14 AIR CLEANER ..............................................................................................................11
4-15 DECOMPRESSION SYSTEM ......................................................................................11
4-16 SECTIONAL VIEW OF ENGINE.................................................................................. 12
5. DISASSEMBLY AND REASSEMBLY.......................................................................16
5-1 PREPARATIONS AND SUGGESTIONS........................................................................ 16
5-2 SPECIAL TOOLS (EH12-2D)......................................................................................... 16
5-3 DISASSEMBLY PROCEDURES.................................................................................... 17
5-4 REASSEMBLY PROCEDURES..................................................................................... 30
5-5 BREAK-IN OPERATION ................................................................................................ 46
6. MAGNETO ................................................................................................................ 46
6-1 OPERATION AND FUNCTION ...................................................................................... 46
6-2 BASIC THEORY ............................................................................................................ 46
6-3 WIRING DIAGRAM....................................................................................................... 48
7. AUTOMATIC DECOMPRESSION SYSTEM............................................................. 49
8a. FLOAT TYPE CARBURETOR (EH09D) ................................................................. 50
8a-1 OPERATION AND CONSTRUCTION.......................................................................... 50
8a-2 DISASSEMBLY AND REASSEMBLY........................................................................... 51