| Catalog No. | O.S. Stock No. | Description | Optional? | Photo |
| OSMG8676 | 22447005 | Screw Set .20 FP-M | | Photo |
| OSMG5673 | 22826140 | 21RZ Exhaust Gasket | | Photo |
| OSMG4222 | 23701010 | Crankcase .21 RZ-R | | |
| OSMG4499 | 23702000 | Crankshaft .21 RZ-B/M | | Photo |
| OSMG4852 | 23703010 | Cylinder & Piston .21 RZ-R | | Photo |
| OSMG5185 | 23704100 | Cylinder Head Marine .21 RZ-M | | Photo |
| OSMG3922 | 23705000 | Connecting Rod .21 RZ B | | Photo |
| OSMG4080 | 23707200 | Cover Plate .21 RZ-R | | |
| OSMG6086 | 23714000 | Gasket Set .21 RZ-B | | Photo |
| OSMG3086 | 23730000 | Rear Bearing .21 RZ-B | | Photo |
| OSMG3042 | 23731000 | Front Bearing .21 RZ-B | | Photo |
| OSMG7476 | 23817000 | Piston Pin Retainer RX/RZ/XM | | Photo |
| OSMG2463 | 23881000 | Carburetor #20G .21 RZ-M | | Photo |
| OSMG7642 | 23906000 | Piston Pin .21 EX-B/R | | Photo |
| OSMG3644 | 23981700 | Carburetor Retainer .21 EX-B/R | | Photo |
| OSMG7896 | 24025923 | Water Nipple #2 | | |
| OSMG2643 | 71802030 | Flywheel #2E .21 EX-M | | Photo |