2020 Yamaha YZ250
General Specifications
| Model | Yamaha YZ250 |
| Year | 2020 |
| 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 |
| Spark Plug Gap | 0.5–0.6 mm (0.020–0.024 in) |
| Cooling System | Liquid-cooled, twin radiators |
| 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 | 2,185 mm (86.0 in) |
| Overall Width | 825 mm (32.5 in) |
| Overall Height | 1,290 mm (50.8 in) |
| Wheelbase | 1,485 mm (58.5 in) |
| Ground Clearance | 360 mm (14.2 in) |
| Seat Height | 970 mm (38.2 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 coil-spring 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, high-speed and low-speed compression damping and rebound damping |
| Rear Suspension Travel | 315 mm (12.4 in) |
| Fork Oil | Yamaha Suspension Oil S1. KYB twin-chamber forks: initial inner damper filling quantity 205 mL (6.93 US oz) per leg, followed by bleeding and discharge of excess oil. Outer chamber standard quantity 320 mL (10.8 US oz) per leg; adjustment range 300–365 mL per leg. Inner and outer chambers are serviced separately. Follow the correct Yamaha service procedure rather than treating the initial damper fill as the final retained oil quantity. |
Brakes & Wheels
| Front Brake | Hydraulic single disc, 250 mm wave rotor, twin-piston caliper (Australian specification) |
| Rear Brake | Hydraulic single disc, 245 mm wave rotor, single-piston caliper |
| Front Wheel Size | 21-inch aluminium spoked rim |
| Rear Wheel Size | 19-inch aluminium spoked rim |
Service Data
| Fuel Type | Premium unleaded petrol, minimum 95 RON (Australian specification), premixed with suitable competition-grade 2-stroke oil |
| Premix Information | 30:1 petrol-to-oil ratio using Yamaha Yamalube 2-R or suitable equivalent competition-grade 2-stroke oil. Approximately 33.3 mL oil per litre of petrol. Follow Yamaha's separate engine break-in instructions where applicable | Premix Calculator |
| Gearbox Oil | Yamalube SAE 10W-40 motorcycle oil meeting the applicable Yamaha specification, API SG or higher and 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 2020 YZ250 was mechanically carried over from the 2019 model, with revised radiator shroud graphics. Maintain the specified 30:1 fuel premix and correct carburettor jetting for temperature, altitude and fuel quality. Standard spark plug: NGK BR8EG, gap 0.5–0.6 mm. Inspect piston, piston rings, reed valves and YPVS components according to operating hours and competition conditions. Regularly change transmission oil, clean and oil the foam air filter, and inspect coolant, chain adjustment, brake pads and spoke tension. Check fork seals, steering-head bearings, suspension linkage bearings and wheel bearings. Use DOT 4 brake fluid where specified by the reservoir cap and service manual. The YZ250 motocross model differs from the YZ250X cross-country two-stroke and the YZ250F four-stroke; verify model identification before ordering engine, gearbox or suspension components. |
2020 Yamaha YZ250 – The Two-Stroke That Stayed True to Its Roots
The 2020 Yamaha YZ250 continued one of motocross racing's most enduring two-stroke traditions. While Yamaha introduced a substantially redesigned YZ450F four-stroke for 2020, its legendary 249cc two-stroke remained mechanically unchanged from the previous year. The only notable update was revised radiator shroud graphics, making the 2020 YZ250 another example of Yamaha refining a proven design rather than replacing it.
The motorcycle's engineering heritage stretched back to the aluminium-frame redesign of 2005 and the introduction of Kayaba Speed Sensitive System suspension in 2006. Yamaha refreshed the bodywork and suspension components in 2015, but retained the established engine design. By 2020, the YZ250 was the only Japanese-manufactured 250cc two-stroke motocross motorcycle available new, giving it a distinctive position in a market increasingly dominated by four-strokes and European two-strokes.
The liquid-cooled engine retained Yamaha's Power Valve System, a 38 mm Keihin PWK carburettor and five-speed transmission. Its responsive power delivery and comparatively straightforward servicing remained attractive to riders who preferred traditional two-stroke performance. Correct jetting and fuel mixture were essential for consistent operation, particularly when riding at different temperatures or elevations. Owners investigating fuel-system components can explore the MXOwners carburettor information and replacement options.
Suspension remained one of the YZ250's strongest features. The 48 mm KYB SSS forks provided 300 mm of travel, complemented by a fully adjustable rear Monocross shock offering 315 mm. Correct spring settings, fresh fork oil and regular linkage maintenance help preserve the handling characteristics that made the motorcycle popular. Owners planning fork maintenance can consult the MXOwners fork oil reference guide.
For present-day owners, the 2020 YZ250 benefits from extensive aftermarket support and mechanical similarities with surrounding model years. Regular piston inspections, clean air filters, fresh gearbox oil and bearing maintenance remain important for reliability. Suitable replacement components can be researched through the MXOwners motorcycle parts finder. Although the 2020 model introduced no major technical changes, it demonstrated why Yamaha's familiar two-stroke continued to attract motocross riders seeking simplicity, responsive performance and a direct connection to the sport's racing heritage.
