| Item | Part No. | Part Name | Qty | Serial No. |
| ENGINE, TIER I (SEE FIG. A0100-01A0) | A20637-A20813- | |||
| YM723900-11100 | CYLINDER HEAD | A20637-A20813- | ||
| 1 | (NSS) | HEAD | A20637-A20813- | |
| 2 | YM123900-11080 | SEAT, VALVE | A20637-A20813- | |
| 3 | YM123900-11090 | SEAT, VALVE | A20637-A20813- | |
| 4 | YM119000-11810 | GUIDE, VALVE | A20637-A20813- | |
| 5 | YM238710-05000 | PLUG | A20637-A20813- | |
| 6 | YM272414-00000 | PLUG | A20637-A20813- | |
| 7 | YM273100-90000 | KEEPER | A20637-A20813- | |
| 8 | YM123900-11100 | VALVE | A20637-A20813- | |
| 9 | YM123900-11110 | VALVE | A20637-A20813- | |
| 10 | YM123900-11120 | SPRING | A20637-A20813- | |
| 11 | YM121850-11150 | SEAL, VALVE | A20637-A20813- | |
| 12 | YM121850-11180 | RETAINER | A20637-A20813- | |
| 13 | YM119171-11370 | CAP | A20637-A20813- | |
| 14 | YM119625-11870 | PROTECTOR | A20637-A20813- | |
| 15 | YM119625-11880 | GASKET | A20637-A20813- | |
| 16 | YM119625-11900 | RETAINER | A20637-A20813- | |
| 17 | YM262160-60302 | STUD | A20637-A20813- | |
| 18 | YM263660-60002 | NUT | A20637-A20813- | |
| 19 | YM123900-07900 | LIFTER | A20637-A20813- | |
| 20 | YM261061-00202 | BOLT | A20637-A20813- | |
| 21 | YM119174-01200 | BOLT | A20637-A20813- |
