1975 Yamaha YZ250B
Specifications and workshop reference information for the 1975 Yamaha YZ250B, 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 | Single-cylinder, two-stroke, air-cooled |
| Displacement | 246 cc |
| Bore × Stroke | 70.0 × 64.0 mm |
| Compression Ratio | 6.8:1 |
| Maximum Power | ~34 hp |
| Maximum Torque | |
| Carburetor | Mikuni VM36 |
| Lubrication | Premix |
| Fuel Mix Ratio | 25:1 |
| Ignition | Magneto |
| Spark Plug | NGK B8ES |
| Spark Plug Gap | 0.5 – 0.6 mm |
Transmission
| Transmission Type | 5-speed constant mesh |
| Clutch | Wet multi-plate |
| Primary Reduction | 3.409 |
| Final Reduction | 3.000 |
| Overall Reduction | |
Dimensions
| Overall Length | 2,150 mm |
| Overall Width | 820 mm |
| Overall Height | 1,200 mm |
| Wheelbase | 1,420 mm |
| Ground Clearance | 280 mm |
| Fuel Tank Capacity | 9.0 L |
Chassis
| Frame Type | Steel single cradle |
| Caster Angle | |
| Trail | |
| Front Suspension | Telescopic forks |
| Rear Suspension | Twin shock |
| Front Suspension Travel | |
| Rear Suspension Travel | |
Brakes & Wheels
| Front Tire | 3.00 – 21 |
| Rear Tire | 4.00 – 18 |
| Front Brake | Drum |
| Rear Brake | Drum |
250cc Other Specs
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