Segment:
Competitive Motocross Segment
Target Audience:
Motocross racers, performance enthusiasts, DIY mechanics
Competitors 2008:
Honda CRF250R, Kawasaki KX250F, Suzuki RM-Z250, KTM 250 SX-F
Engine Architecture:
DOHC, 4-valve, liquid-cooled, 250cc four-stroke
Chassis Design:
Aluminum bilateral beam frame
Suspension Tech:
Kayaba (KYB) Speed Sensitive System (SSS) front forks and rear shock
Engine:
Complete disassembly, inspection, assembly, tuning
Transmission:
Gearbox teardown, inspection, lubrication, clutch service
Fuel System:
Carburetor tuning, cleaning, float adjustment, fuel pump inspection
Ignition System:
CDI, spark plug analysis, ignition timing
Cooling System:
Radiator service, coolant checks, water pump inspection
Suspension:
Front fork (USD) service, rear shock absorber maintenance, adjustments
Brakes:
Hydraulic brake system bleeding, pad replacement, rotor inspection
Electrical System:
Wiring diagrams, lighting, battery maintenance
Chassis:
Frame inspection, steering head bearing service, wheel bearing replacement
Bodywork:
Fairing removal, seat inspection
Maintenance:
Regular service, oil changes, filter replacement, chain adjustment
Repair:
Complete engine rebuild, gearbox repairs, suspension overhauls
Troubleshooting:
Diagnosis of common problems, electrical fault finding, performance issues
Diagnostics:
Step-by-step diagnostic guides for various systems
Torquing:
Critical torque specifications for all fasteners
Depth:
Comprehensive factory-level detail for all repair and maintenance tasks
Visuals:
Illustrations and photographs for clarity
Part Identification:
Includes part diagrams for component identification
Engine Type:
250cc, Liquid-cooled, 4-stroke, DOHC, 4-valve
Bore X Stroke:
77.0 mm x 53.6 mm
Compression Ratio:
12.5:1
Carburetor:
Keihin FCR39 (flat slide, single)
Horsepower Est:
Approx. 38-40 HP (at crankshaft, varies with tuning)
Torque Est:
Approx. 20-22 lb-ft (at crankshaft, varies with tuning)
Fuel Delivery:
Carbureted
Fuel Type:
Unleaded gasoline, 91 octane or higher recommended
Oil Type:
Yamalube 4-stroke Motorcycle Oil (or equivalent SAE 10W-40 API SG or higher)
Oil Capacity:
1.00 L (1.06 US qt) without filter change; 1.10 L (1.16 US qt) with filter change
Type:
Constant-mesh 5-speed sequential
Clutch:
Wet, multiple-disc, cable-operated
Gear Ratios:
1st: 2.615 (34/13), 2nd: 1.933 (29/15), 3rd: 1.500 (27/18), 4th: 1.235 (21/17), 5th: 1.045 (23/22)
Transmission Oil Type:
Yamalube 4-stroke Motorcycle Oil (same as engine oil)
Transmission Oil Capacity:
0.75 L (0.79 US qt)
Safety Certification:
N/A (Off-road vehicle, not designed for road use)
Brakes Front:
Hydraulic disc, 250 mm diameter
Brakes Rear:
Hydraulic disc, 245 mm diameter
Tires Front:
80/100-21 51M
Tires Rear:
110/90-19 62M
Frame Material:
Aluminum bilateral beam
Handlebar:
Aluminum, customizable position
Infotainment System:
N/A (Dedicated Motocross Motorcycle)
Driver Assistance Features:
N/A (Dedicated Motocross Motorcycle)
Connectivity Options:
N/A (Dedicated Motocross Motorcycle)
Engine Management:
Basic ignition timing controlled by CDI unit, carburetor provides fuel delivery.
Engine Oil Change:
Every 10-15 hours of riding or annually
Air Filter Cleaning:
Every 5-10 hours of riding, or as needed based on conditions
Spark Plug Inspection:
Every 15-20 hours of riding
Valve Clearance Check:
Every 20-25 hours of riding
Chain Lubrication Adjustment:
Every 5-10 hours of riding
Engine Oil Spec:
SAE 10W-40, API SG or higher (e.g., Yamalube 4-Stroke)
Coolant Type:
Permanent type antifreeze, 50% mixture with distilled water
Brake Fluid Type:
DOT 3 or DOT 4
Common Wear Items:
Clutch plates, piston rings, valve guides, timing chain, wheel bearings
Carburetor Tuning Sensitivity:
The FCR carburetor can be sensitive to altitude and temperature changes, requiring re-jetting for optimal performance.
Suspension Seals:
Regular inspection and maintenance of fork seals and shock seals are crucial due to the high demands of motocross riding.
Brand Focus:
Yamaha is renowned for its long history in motorcycle racing and performance engineering.
Yz250F Development:
The YZ250F has consistently been a top contender in the 250cc four-stroke class, known for its potent engine and advanced suspension. The 2008 model featured significant updates and refinements over previous generations.
Manufacturing Location:
Japan (Primary)
Production Years:
The YZ250F model line began in 2001.
