Market Segment:
Entry-level to intermediate motocross racing and off-road riding
Key Competitors:
KTM 85 SX, Kawasaki KX85, Suzuki RM85, Honda CR85 (older generation)
Yz85 Reputation:
Known for its powerful engine and competitive chassis, a staple in youth motocross
Manual Benefit:
Enables owners to perform all necessary maintenance and repairs, reducing dependence on dealerships and increasing bike longevity
Engine Systems:
Engine disassembly, assembly, lubrication, cooling, ignition, fuel, exhaust
Transmission Clutch:
Clutch operation, maintenance, repair; Transmission gear inspection, replacement
Chassis Suspension:
Front fork (USD) maintenance and overhaul, rear shock absorber service, swingarm, linkage
Brakes:
Front and rear brake system maintenance, bleeding, caliper and master cylinder service, pad replacement
Electrical System:
Wiring diagrams, lighting, ignition system, charging system, component testing
Fuel System:
Carburetor disassembly, cleaning, adjustment, fuel tank, fuel lines
Cooling System:
Radiator, hoses, coolant, water pump
Exhaust System:
Muffler and pipe inspection and replacement
Wheels Tires:
Wheel bearing service, spoke tensioning, tire changes
Body Frame:
Fairing, seat, handlebar, footpegs, frame inspection
Routine Maintenance:
Oil changes, filter replacements, chain lubrication and adjustment, spark plug checks
Troubleshooting:
Diagnostic charts, common problem identification and solutions
Engine Rebuild:
Piston, cylinder, crankshaft, connecting rod, crankcase service and replacement
Suspension Overhaul:
Fork seal replacement, damper rod service, rear shock rebuild
Brake System Repair:
Piston seal replacement, hydraulic line flushing and replacement
Electrical Diagnostics:
Component testing using multimeter, fault finding
Carburetor Tuning:
Jetting adjustments, idle speed setting, mixture screw adjustments
Wheel Truing:
Spoke tension adjustment for wheel alignment
Assembly Disassembly:
Step-by-step instructions for all major components
Depth Level:
Complete engine rebuilds, advanced suspension tuning, detailed electrical troubleshooting
Diagnostic Capabilities:
Detailed diagnostic flowcharts and specifications
Torque Specifications:
Precise torque values for all fasteners
Clearances:
Engine component clearances (piston-to-cylinder, bearing clearances, etc.)
Wiring Diagrams:
High-quality, detailed electrical schematics
Engine Type:
Liquid-cooled, 2-stroke, reed valve induction
Bore X Stroke:
47.0 mm x 47.1 mm
Displacement:
10.1 cu. in. (163 cc)
Carburetor Model:
Keihin PWK36
Ignition Type:
CDI (Capacitor Discharge Ignition)
Spark Plug Type:
NGK BR9EG
Horsepower Approx:
30-35 hp (estimated)
Torque Approx:
15-18 lb-ft (estimated)
Fuel Type:
Unleaded gasoline, 91-98 octane recommended
Fuel Oil Mixture:
50:1 (Premium 2-stroke oil)
Fuel Tank Capacity:
1.45 US gallons (5.5 L)
Cooling Medium:
Liquid (Ethylene glycol-based coolant)
Oil Change Interval:
Every 10-15 hours of riding or annually, depending on usage
Air Filter Cleaning:
After every few rides, or as needed based on dust conditions
Spark Plug Inspection:
Every 10-20 hours of riding
Chain Lubrication Adjustment:
Every 5-10 hours of riding, check slack before each ride
Top End Rebuild Recommendation:
Typically between 40-60 hours of hard use, depending on maintenance and riding style
Fork Oil Type:
Yamaha Fork Oil G10 or equivalent SAE 10W fork oil
Fork Oil Level:
Refer to manual for specific level (e.g., 110 mm from top of inner tube with spring removed)
Coolant Type:
Yamaha Super Coolant or equivalent permanent type (50% mixture with distilled water)
Common Wear Items:
Piston rings, clutch plates, fork seals, wheel bearings, chain and sprockets due to demanding use.
Carburetor Jetting:
May require re-jetting based on altitude and temperature changes for optimal performance.
Yamaha Offroad Legacy:
Yamaha has a long and successful history in motocross and off-road racing, with the YZ line being a cornerstone of their performance offerings for decades.
Yz85 Development:
The YZ85 has evolved significantly, with continuous improvements in engine performance, suspension technology, and chassis design to remain competitive in youth racing classes.
Production Era:
The YZ85 platform has been in continuous production, with significant updates and redesigns occurring periodically.
