2017 Yamaha YZ250
General Specifications
| Model | Yamaha YZ250 |
| Year | 2017 |
| Category | Motocross / Competition Off-Road |
| Engine Type | Liquid-cooled, single-cylinder, 2-stroke, reed-valve induction with Yamaha Power Valve System (YPVS) |
| Weight | 103 kg (227 lb) wet / curb weight |
Engine
| Displacement | 249 cc |
| Bore x Stroke | 66.4 x 72.0 mm |
| Compression Ratio | 8.9–10.6:1 |
| Fuel System | Keihin PWK38S, 38 mm flat-slide carburettor with throttle-position sensor and reed-valve induction | Replacement Options |
| Ignition | Digital CDI magneto ignition |
| Spark Plug | NGK BR8EG (resistor type) |
| Spark Plug Gap | 0.5–0.6 mm (0.020–0.024 in) |
| Cooling System | Liquid-cooled, twin radiators; coolant capacity 1.20 L |
| Starting System | Kick starter |
Transmission
| Transmission | 5-speed constant-mesh close-ratio manual |
| Clutch | Wet, multi-plate, cable-operated |
| Final Drive | Chain drive; standard gearing 14T front / 50T rear (3.571:1) |
Dimensions
| Overall Length | 2,147 mm (84.4 in) |
| Overall Width | 827 mm (32.6 in) |
| Overall Height | 1,299 mm (51.2 in) |
| Wheelbase | 1,446 mm (56.9 in) |
| Ground Clearance | 367 mm (14.4 in) |
| Seat Height | 976 mm (38.4 in) |
| Fuel Capacity | 8.0 litres (2.1 US gal) |
Chassis
| Frame | Aluminium semi-double-cradle frame with removable rear subframe |
| Front Tyre | 80/100-21 51M, tube type | Tyre Size Guide |
| Rear Tyre | 110/90-19 62M, tube type | Tyre Size Guide |
Suspension
| Front Suspension | 48 mm KYB upside-down Speed Sensitive System (SSS) twin-chamber spring forks, adjustable compression and rebound damping | Fork Oil Levels |
| Front Suspension Travel | 300 mm (11.81 in) |
| Rear Suspension | KYB gas/oil-damped Monocross linkage shock with adjustable spring preload, high-speed and low-speed compression damping and rebound damping |
| Rear Suspension Travel | 315 mm (12.40 in) |
| Fork Oil | Yamaha Suspension Oil S1. KYB twin-chamber forks: inner damper filling quantity 205 mL (6.93 US oz) per leg before bleeding. Outer chamber standard quantity 320 mL (10.8 US oz) per leg; adjustment range 300–365 mL per leg. The inner damper must be correctly bled and excess oil discharged according to Yamaha's service procedure. Inner and outer chamber quantities are separate. |
Brakes & Wheels
| Front Brake | Hydraulic single disc, 270 mm rotor on updated US-market specification; 250 mm listed for some other market specifications. Twin-piston caliper. Verify fitted rotor diameter before ordering parts. |
| Rear Brake | Hydraulic single disc, 245 mm rotor, single-piston caliper |
| Front Wheel Size | 21 x 1.60-inch aluminium spoked rim |
| Rear Wheel Size | 19 x 2.15-inch aluminium spoked rim |
Service Data
| Fuel Type | Premium unleaded petrol, minimum 95 RON, mixed with suitable competition-grade 2-stroke oil |
| Premix Information | 30:1 petrol-to-oil ratio using Yamaha Yamalube 2-R or suitable equivalent 2-stroke oil. Approximately 33.3 mL oil per litre of petrol | Premix Calculator |
| Gearbox Oil | Yamalube SAE 10W-40 motorcycle oil, API SG or higher, JASO MA. Periodic transmission oil change: 0.75 L (750 mL). Total transmission oil capacity: 0.80 L (800 mL). |
| Air Filter | Reusable, oil-treated foam air-filter element |
| Service Notes | The 2017 YZ250 continued the established two-stroke engine, aluminium chassis and KYB SSS suspension introduced in earlier generations. Updated graphics were accompanied by a larger 270 mm front brake rotor in the US specification, replacing the previous 250 mm disc. Some regional listings retained a 250 mm specification, so confirm the installed brake assembly before purchasing replacement parts. Maintain the specified 30:1 fuel premix and adjust carburettor jetting for temperature, altitude and fuel quality. Inspect piston, piston rings, reed valves and YPVS components according to competition operating hours. Spark plug tightening torque: 20 Nm (14 ft-lb). Clean and oil the foam air filter regularly and change transmission oil frequently under racing conditions. Inspect fork seals, steering-head bearings, suspension linkage bearings, wheel bearings, coolant, brake pads, drive-chain tension and spoke tension. The YZ250 motocross model differs from the YZ250X cross-country model in transmission ratios, suspension settings and equipment. Verify model identification when ordering replacement components. |
2017 Yamaha YZ250 – Proven Two-Stroke Performance with Improved Braking
The 2017 Yamaha YZ250 continued the Japanese manufacturer's long-standing commitment to two-stroke motocross. Following the significant bodywork and suspension updates introduced for 2015, the 2017 motorcycle remained largely unchanged mechanically. However, Yamaha introduced a larger 270 mm front brake rotor for the US-market model, improving braking performance while retaining the familiar engine and chassis combination that had made the YZ250 a favourite among traditional motocross riders.
The 249cc liquid-cooled two-stroke engine retained Yamaha's Power Valve System, a 38 mm Keihin PWK carburettor and a five-speed close-ratio gearbox. Its immediate throttle response, strong midrange acceleration and relatively straightforward maintenance remained major attractions. Correct carburettor jetting continued to be important for consistent performance in changing riding conditions. Owners investigating fuel-system maintenance can explore the MXOwners carburettor information and replacement options.
Suspension remained one of the YZ250's strongest features. The 48 mm KYB Speed Sensitive System forks provided 300 mm of travel, complemented by a fully adjustable rear Monocross shock with 315 mm of travel. These components offered predictable handling and excellent bump absorption, particularly when correctly maintained. The MXOwners fork oil levels and suspension guide can assist owners planning routine fork servicing.
By 2017, the YZ250's aluminium frame had been in production for more than a decade, yet the motorcycle remained popular with riders who valued simplicity and familiar handling. Its established design also meant extensive aftermarket support and good availability of replacement components. Owners restoring or maintaining a machine can investigate suitable parts through the MXOwners motorcycle parts finder.
The 2017 YZ250 demonstrated Yamaha's continued confidence in the traditional two-stroke motocross motorcycle. While four-strokes dominated much of professional racing, the YZ250 offered responsive performance, straightforward top-end servicing and an engaging riding experience. With its proven suspension, established engine and braking improvement in selected markets, the 2017 model remains an appealing example of Yamaha's enduring two-stroke heritage.
