| Yamaha RD specs- | *These are aircooled models. | |||||
| RD125 | RD200 | RD250 | RD350 A/B | RD400 | ||
| Pist. Side Clearance (in.) | .0014-.0016 | .0016-.0018 | .0016-.0018 | .0016-.0018 | .0012-.0014 | |
| Ring End Gap (in.) | 0.008-0.016 | 0.006-0.014 | 0.006-0.014 | 0.008-0.016 | 0.012-0.020 | |
| Oil Pump-Min stroke (mm) | 0.20-0.25 | 0.20-0.25 | 0.20-0.25 | 0.20-0.25 | 0.20-0.25 | |
| Compresion Ratio | 7.1:1 | N/A | 6.6:1 | 6.6:1 | 6.2:1 | |
| BoreXStroke (mm) | 52x46 | N/A | 54x54 | 64x54 | 64x62 | |
| Weight (stock)-LBS | 256 . | N/A | 309 . | 315 . | 342 . | |
| Carb Type | Tekiei-Y20P-1A | N/A | Mik- VM28SC | Mik- VM28SC | Mik- VM28SC | |
| Main Jet | 94 . | 94 . | 120 . | 140 ('75 =110) | 115 . | |
| Pilot Jet | 44 . | 44 . | 30 . | 25 . | 25 . | |
| Float Level (mm) | 20 | 20 | 15 | 15 . | 23 | |
| Jet Needle | 4D50-2 | 4F51-2 | 514-3 | 514-3 | 5L1-3 | |
| Needle Jet | N30 | N80 | O-8 | O-8 | P-2 | |
| Air Screw Turns out | 1 1/2 | 1 1/4 | 1 1/4 | 1 3/4 | 1 1/2 | |
| Point Gap (mm) | 0.30-0.40 | 0.30-0.40 | 0.30-0.40 | 0.30-0.40 | 0.30-0.40 | |
| Spark Plug -NGK # | B8HS | B8HS | B9HS | B9HS | B8ES | |
| Plug Gap (mm) | 0.6-0.7 | 0.6-0.7 | 0.5-0.6 | 0.5-0.6 | 0.6-0.7 | |
| Timing- @mm BTDC | 1.8 | 1.8 | 2 | 2 | 2.3 | |
| Transmisson Ratios: | ||||||
| First | 2.833 | N/A | 2.571 | 2.571 | 2.571 | |
| Second | 1.705 | N/A | 1.777 | 1.777 | 1.777 | |
| Third | 1,250 | N/A | 1.318 | 1.318 | 1.318 | |
| Fourth | 1.045 | N/A | 1.04 | 1.04 | 1.083 | |
| Fifth | 0.916 | N/A | 0.888 | 0.888 | 0.961 | |
| Sixth | N/A | N/A | 0.785 | 0.785 | 0.888 | |
