| Attribute | Value |
| General |
| Production from | 2018 year |
| Make | Yamaha |
| Model | Yamaha YZ125 |
| Category | Cross / motocross |
| Engine and transmission |
| Engine type | Single cylinder, two-stroke |
| Valves per cylinder | Add |
| Fuel system | Carburettor. Mikuni TMX 38 |
| Engine details | Reed-valve-inducted |
| Displacement | 124 cm³ |
| Power | Add |
| Max RPM | Add |
| Fuel consumption | Add |
| Cooling system | Liquid |
| Transmission type,final drive | Chain |
| Torque | Add |
| Bore | 54 mm |
| Stroke | 54.5 mm |
| Gearbox | 6-speed |
| Greenhouse gases | Add |
| Fuel control | Add |
| Emission details | Add |
| Driveline | Add |
| Ignition | CDI |
| Clutch | Multiplate wet clutch |
| Lubrication system | Premix |
| Compression | 10.7:1 |
| Exhaust system | Add |
| Chassis |
| Front suspension | KYB® Speed-Sensitive System inverted fork; fully adjustable |
| Rear suspension | KYB® single shock; fully adjustable |
| Front brakes | Single disc. Hydraulic. |
| Rear brakes | Single disc. Hydraulic. |
| Diameter | 245 mm |
| Frame type | Semi-double cradle aluminium frame |
| Front tyre | 80/100-21 |
| Rear tyre | 100/90-19 |
| Seat | Add |
| Wheels | Dunlop® MX52 |
| Front wheel travel | 300 mm |
| Rear wheel travel | 315 mm |
| Trail | 109 mm |
| Rake (fork angle) | 26 degree |
| Other |
| Battery capacity | Add |
| Starter | Kick |
| Color options | |
| Carrying capacity | Add |
| Light | Add |
| Instruments | Add |
| Electrical Voltage | Add |
| Dimensions |
| Wheelbase | 1,443 mm |
| Kerb weight | 93.9 kg |
| Dry weight | Add |
| Power/weight ratio | Add |
| Overall height | 1,295 mm |
| Overall length | 2,136 mm |
| Overall width | 828 mm |
| Seat height | 975 mm |
| Alternate seat height | Add |
| Ground clearance | 366 mm |
| Front percentage of weight | Add |
| Rear percentage of weight | Add |
| Performance |
| Top speed | Add |
| Acceleration 0-100 km/h | Add |
| Length | Add |
| Reserve fuel capacity | Add |
| Fuel capacity | 8 l |
| Oil capacity | 0.7 l |
| Width | Add |
| Height | Add |