1981 KTM 125 MX Specifications and Specs
Specifications and workshop reference information for the 1981 KTM 125 MX, 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 | Air-cooled, single-cylinder, 2-stroke |
| Displacement | 124 cc |
| Bore × Stroke | 54.0 × 54.0 mm |
| Compression Ratio | Approx. 7.5:1 |
| Maximum Power | Approx. 20–22 hp |
| Maximum Torque | N/A |
| Carburetor | Bing / Dell’Orto (approx. 28–30 mm) | Replacement Options |
| Lubrication | Premix |
| Fuel Mix Ratio | 25:1 – 32:1 | Premix Calculator |
| Ignition | Motoplat CDI |
| Spark Plug | NGK B8ES |
| Spark Plug Gap | 0.6 – 0.7 mm |
Transmission
| Transmission Type | 6-speed manual |
| Clutch | Wet multi-plate |
| Primary Reduction | N/A |
| Final Reduction | Chain |
| Overall Reduction | N/A |
Dimensions
| Overall Length | N/A |
| Overall Width | N/A |
| Overall Height | N/A |
| Wheelbase | Approx. 1400 mm |
| Ground Clearance | N/A |
| Fuel Tank Capacity | Approx. 9.0 L |
| Bearing Sizes |
Bearing Finder |
Chassis
| Frame Type | Steel single cradle |
| Caster Angle | N/A |
| Trail | N/A |
| Front Suspension | Telescopic forks | Fork Oil Levels |
| Rear Suspension | Twin shock swingarm |
| Front Suspension Travel | Approx. 250 mm |
| Rear Suspension Travel | Approx. 120 mm |
Brakes & Wheels
125cc Other Specs
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