Segment:
Motocross/Off-Road Competition
Competitors:
KTM 250 EXC, Honda CR250R, Suzuki RM250
Performance Focus:
Aggressive power delivery, agile handling, proven motocross performance
Manual Benefit:
Enables owners and mechanics to maintain, diagnose, and repair the 1997 Yamaha YZ250 effectively, preserving its performance and longevity.
Engine:
Top-end rebuild, bottom-end assembly, lubrication, cooling, ignition system, carburetor tuning, exhaust system
Transmission:
Clutch operation, gear shifting mechanism, transmission disassembly and assembly, lubrication
Chassis:
Frame inspection, suspension (forks, shock absorber) servicing and adjustment, steering system, swingarm maintenance
Brakes:
Hydraulic front and rear brake systems, caliper overhaul, master cylinder servicing, bleeding procedures, pad replacement
Electrical:
Wiring diagrams, lighting system, ignition coil, stator, CDI unit, troubleshooting electrical faults
Fuel System:
Fuel tank maintenance, fuel petcock, carburetor service and adjustment (Mikuni VM series), fuel line inspection
Bodywork:
Fairing removal and installation, seat maintenance, fender mounting
Maintenance:
Regular servicing, oil changes, filter cleaning/replacement, spark plug maintenance, chain adjustment, bearing lubrication
Repair:
Complete engine overhaul, carburetor rebuild, suspension fork seal replacement, wheel bearing replacement, exhaust pipe repair
Troubleshooting:
Diagnostic charts for common performance issues, starting problems, electrical faults, and component failures
Depth:
Comprehensive, covering from basic maintenance to full engine and component rebuilds, including detailed specifications and diagnostic procedures.
Engine Type:
Liquid-cooled, 2-stroke, Reed valve, YPVS (Yamaha Power Valve System)
Bore X Stroke:
68.0 mm x 68.0 mm
Compression Ratio:
8.4:1 (or similar, check manual for exact)
Ignition:
CDI (Capacitor Discharge Ignition)
Horsepower:
Approx. 45-50 HP (manufacturer figures often vary, expect peak performance)
Torque:
Not officially specified, but strong mid-range power is characteristic.
Carburetor:
Mikuni VM38SS (38mm)
Fuel Type:
Unleaded gasoline with 2-stroke oil pre-mix (refer to manual for specific octane and mix ratio)
Fuel Capacity:
8.0 Liters (2.1 US gallons)
Transmission Oil Type:
Yamaha Gear Oil 10W-30, or API GL-4 SAE 80 hypoid gear oil
Transmission Oil Capacity:
0.65 Liters (0.69 US quarts)
Features:
N/A (Pure performance off-road motorcycle, no infotainment features).
Features:
N/A (No electronic rider aids or driver assistance systems).
Features:
N/A (No electronic connectivity features).
Ypvs Control:
The YPVS is an electromechanical system that opens and closes exhaust ports based on engine RPM to broaden the powerband.
Oil Change Transmission:
Every 10-15 hours of riding or annually. Check manual for specific recommendation.
Air Filter Cleaning:
After every few rides, or more frequently in dusty conditions.
Spark Plug Inspection:
Every 5-10 hours of riding.
Engine Top End Rebuild:
Recommended every 30-50 hours of hard riding, or as indicated by performance degradation.
Coolant Type:
Yamaha Super Coolant or equivalent ethylene glycol-based coolant with distilled water (50/50 mix). Check manual for exact specification.
Premix Oil:
High-quality 2-stroke synthetic or semi-synthetic racing oil. Refer to manual for specific brand and ratio recommendations.
Ypvs Sticking:
The YPVS mechanism can sometimes become sticky due to carbon buildup, requiring cleaning. The manual details the procedure.
Carburetor Tuning:
Proper carburetor jetting and adjustment are crucial for optimal performance. The manual provides detailed tuning guidelines.
Clutch Wear:
As with any performance motorcycle, clutch wear is normal and requires periodic inspection and replacement. The manual guides this process.
Cleaning And Lubrication:
Regular cleaning of the air filter, chain lubrication, and general inspection are vital for longevity.
Yamaha Motorsport:
Yamaha has a rich legacy in motocross and off-road racing, with a strong track record of innovation and performance.
Yz Series:
The YZ250 has been a cornerstone of Yamaha's motocross lineup for decades, undergoing continuous development and refinement.
Production Period:
The YZ250 model has been in continuous production, with the 1997 model representing a specific iteration of this long-running lineage.
