2009 Yamaha YZ250F
General Specifications
| Model | Yamaha YZ250F |
| Year | 2009 |
| Category | Motocross |
| Engine Type | Liquid-cooled, 4-stroke, DOHC, 5-valve single-cylinder |
| Weight | 93.0 kg dry |
Engine
| Displacement | 249 cc |
| Bore x Stroke | 77.0 x 53.6 mm |
| Compression Ratio | 13.5:1 |
| Fuel System | Keihin FCR-MX37 flat-slide carburettor | Replacement Options |
| Ignition | CDI magneto |
| Spark Plug | NGK CR8E |
| Spark Plug Gap | 0.7-0.8 mm (0.028-0.031 in) |
| Cooling System | Liquid cooled |
| Starting System | Kick starter with automatic decompression |
Transmission
| Transmission | 5-speed constant-mesh |
| Clutch | Wet multi-plate |
| Final Drive | Chain, 13-tooth front / 49-tooth rear sprocket, 3.769:1 |
Dimensions
| Overall Length | 2,161 mm |
| Overall Width | 825 mm |
| Overall Height | 1,303 mm |
| Wheelbase | 1,468 mm |
| Ground Clearance | 370 mm |
| Seat Height | 986 mm |
| Fuel Capacity | 7.0 L |
Chassis
Suspension
| Front Suspension | 48 mm KYB inverted Speed Sensitive System cartridge fork, adjustable compression and rebound damping | Fork Oil Levels |
| Front Suspension Travel | 300 mm (11.8 in) |
| Rear Suspension | Link-type Monocross with KYB gas/oil shock, titanium spring and adjustable preload, high-/low-speed compression and rebound damping |
| Rear Suspension Travel | 310 mm (12.2 in) |
| Fork Oil | Yamaha Suspension Oil S1; damper assembly approximately 195 cc; standard outer chamber oil quantity approximately 340 cc per fork |
Brakes & Wheels
| Front Brake | Hydraulic single disc, 250 mm |
| Rear Brake | Hydraulic single disc, 245 mm |
| Front Wheel Size | 21 x 1.60 in aluminium spoked wheel |
| Rear Wheel Size | 19 x 1.85 in aluminium spoked wheel |
Service Data
| Fuel Type | Premium unleaded petrol, minimum 95 RON |
| Premix Information | Not applicable - 4-stroke engine |
| Gearbox Oil | Engine and transmission share the same dry-sump engine oil supply; approximately 1.05 L periodic oil change, 1.15 L with oil filter replacement and 1.30 L total capacity. API SG or higher, JASO MA motorcycle oil. |
| Air Filter | Wet-type foam element |
| Service Notes | Dry-sump lubrication. Maintain frequent oil and filter changes, inspect valve clearance regularly, keep the foam air filter clean and correctly oiled, and maintain correct FCR carburettor jetting and accelerator-pump operation. The 2009 model retained the established aluminium-frame, five-valve carburetted platform with targeted engine, exhaust and chassis refinements. |
2009 Yamaha YZ250F: The Mature Carburetted Five-Valve YZ250F
The 2009 Yamaha YZ250F was an evolutionary update rather than a new generation. By this stage Yamaha had spent several years refining the aluminium-framed YZ250F introduced in 2006, and the basic formula remained unchanged: a 249 cc five-valve four-stroke engine, Keihin FCR-MX37 carburettor, aluminium semi-double-cradle frame and KYB suspension.
The engine retained its 77.0 x 53.6 mm bore and stroke and 13.5:1 compression ratio, but Yamaha continued to refine intake, ignition and exhaust characteristics to improve usable power. The Keihin FCR carburettor remained central to the bike's throttle response, and correct jetting, accelerator-pump function and hot-start operation are still important on surviving examples. Owners servicing one can compare options through the MXOwners carburettor reference.
Suspension remained a major strength of the model. The 48 mm KYB Speed Sensitive System fork provided 300 mm of travel, while the linkage-operated Monocross rear suspension offered around 310 mm. The fork and shock were revised in detail for 2009 to improve balance and control while retaining the familiar overall design. Fork service information can be checked through the MXOwners fork oil reference.
The aluminium chassis, five-speed gearbox and shared dry-sump engine and transmission lubrication system were also retained. Regular oil changes, clean air filtration and valve-clearance inspection remain essential on these high-revving competition engines, especially now that many examples are more than fifteen years old.
For owners today, the 2009 YZ250F represents one of the most developed versions of Yamaha's long-running carburetted five-valve platform. When restoring or maintaining one, model-year parts should still be checked carefully through the MXOwners Parts Finder, while the standard 80/100-21 front and 100/90-19 rear tyre sizes can be compared using the MXOwners Tyre Size Guide.
