1983 Yamaha YZ125 Specifications and Specs
Specifications and workshop reference information for the 1983 Yamaha YZ125, including engine, chassis, service data and setup details.
Note: Specs are compiled from factory data, manuals and owner feedback. Bikes vary — if yours is different, jump into the forum and share it.
General Specifications
| Engine Type | 124cc, liquid-cooled, 2-stroke single |
| Displacement | 124 cc |
| Bore × Stroke | 56.0 mm × 50.0 mm |
| Compression Ratio | ~7.4:1 |
| Maximum Power | ~30 hp |
| Maximum Torque | ~19 Nm |
| Carburetor | Mikuni VM34SS | Replacement Options |
| Lubrication | Premix |
| Fuel Mix Ratio | 32:1 | Premix Calculator |
| Ignition | CDI |
| Spark Plug | NGK BR9ES |
| Spark Plug Gap | 0.6–0.7 mm |
Transmission
| Transmission Type | 6-speed manual |
| Clutch | Wet multi-plate |
| Primary Reduction | ~3.409 |
| Final Reduction | ~3.769 (49/13) |
| Overall Reduction | N/A |
Dimensions
| Overall Length | ~2130 mm |
| Overall Width | ~820 mm |
| Overall Height | ~1230 mm |
| Wheelbase | ~1420 mm |
| Ground Clearance | ~330 mm |
| Fuel Tank Capacity | ~8.5 L |
| Bearing Sizes |
Bearing Finder |
Chassis
| Frame Type | Steel single cradle |
| Caster Angle | ~27.0° |
| Trail | ~115 mm |
| Front Suspension | KYB conventional forks | Fork Oil Levels |
| Rear Suspension | Monocross monoshock |
| Front Suspension Travel | ~290 mm |
| Rear Suspension Travel | ~300 mm |
Brakes & Wheels
125cc Other Specs
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