Market Segment:
High-performance motocross competition segment
Target User:
Motocross racers, serious off-road enthusiasts, mechanics
Key Competitors:
KTM 250 SX-F, Honda CRF250R, Kawasaki KX250F, Suzuki RM-Z250
Engine Technology:
Yamaha's signature DOHC, four-valve, liquid-cooled engine with a focus on accessible power delivery and broad torque curve.
Suspension Technology:
Industry-leading KYB Speed Sensitive System (SSS) front forks and KYB rear shock, offering exceptional damping and adjustability.
Chassis Design:
Lightweight aluminum bilateral beam frame for optimal mass centralization and handling.
Fuel Injection:
Advanced Mikuni DFI (Digital Fuel Injection) system for precise fuel metering and improved throttle response across varying conditions.
Manual Benefit:
Enables owners and technicians to perform all necessary maintenance, repairs, and tuning for peak performance and longevity.
Engine:
Complete internal and external engine components, top-end and bottom-end rebuilds
Fuel System:
Fuel injection system, fuel pump, injectors, fuel tank
Ignition System:
CDI, spark plug, ignition coil, timing
Cooling System:
Radiator, water pump, coolant passages, hoses
Transmission Drivetrain:
Clutch, gearbox, shift mechanism, final drive (chain and sprockets)
Suspension Front:
KYB Speed Sensitive System (SSS) forks, adjustments, internal components, seals
Suspension Rear:
KYB monoshock, linkage system, adjustments, internal components, seals
Brakes Front:
Hydraulic disc brake system, caliper, master cylinder, rotor, pads
Brakes Rear:
Hydraulic disc brake system, caliper, master cylinder, rotor, pads
Wheels Tires:
Wheel assembly, spokes, bearings, tire changing
Electrical System:
Wiring diagrams, battery, lighting (if applicable), starter system (if applicable)
Frame Chassis:
Frame, subframe, bodywork, controls (handlebars, levers, pedals)
Fuel Injection System:
ECU, throttle body, sensors, troubleshooting fuel delivery issues
Maintenance Routine:
Regular checks, lubrication, filter changes, chain adjustment
Major Overhaul:
Complete engine tear-down and rebuild procedures
Troubleshooting Diagnostics:
Step-by-step guides for identifying and resolving common issues
Suspension Setup Rebuild:
Fork and shock internal rebuild, seal replacement, clicker adjustments
Brake Service:
Brake bleeding, pad replacement, caliper servicing
Clutch Service:
Clutch adjustment, plate replacement
Electrical Component Testing:
Testing of ignition system, sensors, and wiring
Depth:
Comprehensive, covering all aspects from basic maintenance to full engine rebuilds and specialized system diagnostics.
Detail Level:
Detailed text, step-by-step instructions, high-quality pictures, and clear part diagrams.
Specification Detail:
Includes critical torque specifications for all fasteners.
Engine Type:
Four-stroke, DOHC, 4-valve
Bore X Stroke:
77.0 mm x 53.6 mm
Compression Ratio:
13.5:1
Starting System:
Primary kick
Horsepower Estimated:
Approx. 38-40 HP (at crankshaft, varies by tuning)
Torque Estimated:
Approx. 20-22 lb-ft (at crankshaft, varies by tuning)
Fuel System:
Mikuni DFI, 44mm throttle body with dual injectors
Fuel Type:
Unleaded gasoline, premium octane (91+ recommended)
Fuel Tank Capacity:
7.0 L (1.85 gal)
Oil Change Interval:
Refer to manual for specific hours/miles, typically every 10-15 hours of moderate use.
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions (e.g., every few hours).
Spark Plug Inspection:
Refer to manual for mileage/hour interval, typically inspect annually or every 25 hours.
Valve Clearance Check:
Crucial maintenance, refer to manual for interval (e.g., every 25-30 hours for competitive use).
Engine Oil Type:
Yamalube 4 (10W-40) or equivalent API SG or higher, JASO MA compatible
Engine Oil Capacity:
0.80 L (0.85 US qt) for oil change, 0.90 L (0.95 US qt) with filter change
Coolant Type:
High-quality engine coolant, mixture of 50% ethylene glycol and 50% distilled water
Common Wear Items:
Clutch plates, piston, piston rings, valve seats, timing chain, wheel bearings, suspension seals.
Potential Problems From Manual:
The manual would detail specific potential issues like valve clearance drift, clutch fade, and wear on the fuel injector system, along with their diagnostic and repair procedures.