2014 Yamaha YZ250
General Specifications
| Model | Yamaha YZ250 |
| Year | 2014 |
| Category | Motocross / Competition Off-Road |
| Engine Type | Liquid-cooled, single-cylinder, 2-stroke, piston 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 (effective compression ratio varies with exhaust-port timing) |
| Fuel System | Keihin PWK38S, 38 mm flat-slide carburettor with reed-valve induction | Replacement Options |
| Ignition | 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 approximately 1.20 L |
| Starting System | Kick starter |
Transmission
| Transmission | 5-speed constant-mesh manual |
| Clutch | Wet, multi-plate, cable-operated |
| Final Drive | Chain drive; standard gearing 14T front / 50T rear (3.571:1) |
Dimensions
| Overall Length | 2,179 mm |
| Overall Width | 827 mm |
| Overall Height | 1,307 mm |
| Wheelbase | 1,481 mm |
| Ground Clearance | 382 mm |
| Seat Height | 994 mm |
| Fuel Capacity | 8.0 litres |
Chassis
| Frame | Aluminium semi-double-cradle frame |
| Front Tyre | 80/100-21 51M, tube type (USA / Australia specification) | Tyre Size Guide |
| Rear Tyre | 110/90-19 62M, tube type (USA / Australia specification) | Tyre Size Guide |
Suspension
| Front Suspension | 48 mm KYB upside-down Speed Sensitive System (SSS) twin-chamber cartridge forks, adjustable compression and rebound damping | Fork Oil Levels |
| Front Suspension Travel | 300 mm (11.8 in) |
| Rear Suspension | KYB gas/oil-damped Monocross linkage shock with adjustable spring preload, compression and rebound damping |
| Rear Suspension Travel | 315 mm (12.4 in) |
| Fork Oil | Yamaha Suspension Oil S1. KYB twin-chamber forks: inner damper assembly 205 mL per leg; outer chamber standard approximately 330 mL per leg. Inner and outer chamber quantities are separate. Verify the correct outer-chamber quantity and adjustment range against the 2014 regional service manual before servicing. |
Brakes & Wheels
| Front Brake | Hydraulic single disc, 250 mm rotor, twin-piston caliper |
| 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 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 2014 YZ250 was mechanically carried over from the 2013 model, with updated graphics. Maintain the specified 30:1 fuel premix and adjust carburettor jetting for temperature, altitude and operating conditions. 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. Change transmission oil frequently under racing conditions. Inspect fork seals, suspension linkage bearings, steering-head bearings, wheel bearings, brake pads, coolant, chain tension and spoke tension. Regional specifications and original carburettor settings may vary. The 2014 model retains the earlier bodywork and suspension configuration, before the styling and front suspension revisions introduced for 2015. |
2014 Yamaha YZ250 – The Last of the Classic-Style Two-Strokes
The 2014 Yamaha YZ250 marked the final year of the familiar bodywork design that had defined Yamaha's aluminium-framed two-stroke motocross motorcycles for nearly a decade. While the company's four-stroke range was receiving significant technical development, the YZ250 continued with its proven engine, chassis and suspension combination. Compared with the 2013 model, changes were limited primarily to revised graphics.
The foundations of the motorcycle dated back to Yamaha's major 2005 redesign, which introduced the lightweight aluminium frame. The following year brought the highly regarded Kayaba Speed Sensitive System suspension. By 2014, the combination had become well established, offering responsive handling and suspension performance that remained competitive despite the design's age.
Its 249cc liquid-cooled engine retained Yamaha's Power Valve System, a 38 mm Keihin PWK carburettor and a five-speed transmission. The engine's strong midrange, lively throttle response and comparatively straightforward maintenance continued to attract riders who preferred two-strokes over increasingly sophisticated four-stroke machines. Correct carburettor jetting was particularly important for consistent performance, and owners can investigate the MXOwners carburettor information and replacement options when maintaining the fuel system.
The 2014 YZ250 also retained its 48 mm KYB SSS forks and adjustable rear Monocross shock. These components helped establish the motorcycle's reputation for predictable handling on rough motocross circuits. Regular suspension servicing remains worthwhile, particularly on older examples. The MXOwners fork oil reference guide provides additional information for maintenance and setup.
For owners today, the 2014 model offers a proven platform with extensive aftermarket support. Keeping the engine healthy requires regular piston inspections, clean air filters, fresh transmission oil and attention to the power-valve mechanism. Replacement components can be researched through the MXOwners motorcycle parts finder. With refreshed styling and suspension components arriving for 2015, the 2014 YZ250 represents the end of a distinctive chapter in Yamaha's two-stroke motocross history.
