Model Segment:
Entry-level to intermediate performance motocross motorcycle
Target Audience:
Junior motocross racers and recreational riders seeking a capable and reliable machine
Key Competitors:
KTM 85 SX, Kawasaki KX85, Honda CR85R, Suzuki RM85
Engine Configuration:
Liquid-cooled, 2-stroke, single-cylinder engine known for its strong power delivery
Suspension Technology:
Often equipped with high-quality KYB suspension components, renowned for their performance and adjustability
Chassis Design:
Lightweight and strong chassis providing agility and stability on the track
Transmission Type:
6-speed constant mesh transmission for precise gear changes
Primary Coverage:
Comprehensive service, repair, and troubleshooting for Yamaha YZ85 motorcycles
Geographic Coverage:
Global Yamaha specifications, assuming North American market focus unless otherwise specified
Estimated Page Count:
Refer to product listing for exact count; typically 300-500 pages for comprehensive manuals
Manual Type:
Service/Repair/Workshop Manual
Manual Completeness:
Full Service/Repair Manual
Engine Systems:
Top-end rebuild (cylinder, piston, rings), bottom-end rebuild (crankshaft, bearings, seals), cooling system, lubrication system, fuel system (carburetor), ignition system, exhaust system
Transmission Drivetrain:
Clutch assembly, gearbox internals (gears, shift drum, forks), final drive (chain, sprockets)
Chassis Suspension:
Frame, front fork (KYB SSS or similar), rear shock absorber (Monocross), swingarm, linkage, steering system
Brakes:
Front and rear hydraulic disc brake systems (calipers, master cylinders, lines, pads, rotors)
Electrical System:
Ignition system components, wiring diagrams, lighting (if applicable for off-road), battery (if equipped)
Bodywork Controls:
Handlebars, controls (throttle, clutch lever, brake lever), footpegs, seat, plastic body panels (shrouds, fenders, side plates)
Routine Maintenance:
Oil changes, filter cleaning/replacement, chain adjustment, spark plug inspection/replacement, air filter service, brake pad inspection, coolant level check
Troubleshooting:
Diagnostic procedures for common starting issues, engine performance problems, electrical faults, and handling quirks
Engine Rebuild:
Detailed steps for complete engine disassembly, inspection, component replacement (piston, rings, con-rod, crankshaft, seals, gaskets), and reassembly
Suspension Service:
Fork seal replacement, fork oil changes, shock absorber service, linkage bearing maintenance
Carburetor Tuning:
Carburetor disassembly, cleaning, jetting adjustments, float bowl settings
Wheel Tire Service:
Tire changes, wheel bearing maintenance, spoke tensioning (if applicable)
Diagnostic Capability:
Advanced diagnostics with detailed specifications and troubleshooting flowcharts
Repair Scope:
Complete overhaul and repair procedures, including component replacement and alignment specifications
Calibration Adjustment:
Detailed specifications for carburetor jetting, ignition timing, suspension settings, and chain slack
Engine Type:
Liquid-cooled, 2-stroke, reed valve, single-cylinder
Displacement:
84.7 cc (This is a standard for the YZ85)
Bore X Stroke:
Approx. 47.5 mm x 47.8 mm (Spec to be confirmed in manual)
Compression Ratio:
Typically around 8.6:1 (Spec to be confirmed in manual)
Carburetor Model:
Likely a Keihin PWK series (e.g., PWK38) or Mikuni TMX (Spec to be confirmed in manual)
Horsepower:
Estimated 20-25 HP (Varies with tuning and year; exact figures in manual)
Torque:
Estimated 15-18 Nm (Varies; exact figures in manual)
Fuel Delivery:
Carbureted
Fuel Type:
Unleaded gasoline with appropriate octane rating (91 or higher recommended for performance)
Fuel Oil Mix:
Pre-mix (e.g., 20:1 or 32:1, depending on oil and usage - SPECIFIC RATIO IN MANUAL)
Fuel Tank Capacity:
Approx. 5.0 Liters (1.3 US gal) (Spec to be confirmed in manual)
Transmission Type:
6-speed constant mesh
Clutch Type:
Wet, multiple-disc, cable-actuated
Optional Gear Ratios:
N/A (Standardized factory ratios)
Transmission Fluid Type:
Yamaha Gear Oil, SAE 10W-30 or equivalent motorcycle-specific transmission oil (SPECIFIC TYPE AND CAPACITY IN MANUAL)
Final Drive:
Chain drive (e.g., 428 or 520 series chain, specific sprocket teeth count in manual)
Length:
Approx. 1805 mm (71.1 in) (Spec to be confirmed in manual)
Width:
Approx. 740 mm (29.1 in) (Spec to be confirmed in manual)
Height:
Approx. 1135 mm (44.7 in) (Spec to be confirmed in manual)
Wheelbase:
Approx. 1255 mm (49.4 in) (Spec to be confirmed in manual)
Ground Clearance:
Approx. 315 mm (12.4 in) (Spec to be confirmed in manual)
Dry Weight:
Approx. 72 kg (159 lbs) (Spec to be confirmed in manual)
Wet Weight:
Approx. 79 kg (174 lbs) (Spec to be confirmed in manual)
Oil Change Interval:
Refer to manual; typically after every few race days or a set number of hours of use for premix engines.
Air Filter Cleaning:
Frequent cleaning recommended, after every ride or few rides depending on conditions.
Spark Plug Replacement:
As needed, or per manual's recommendation (e.g., 20-40 hours of use).
Piston Ring Replacement:
Recommended at regular top-end rebuild intervals, typically 40-60 hours of hard use (precise interval in manual).
Clutch Inspection:
Regular inspection for wear, fluid level, and free play.
Engine Oil Type:
N/A (2-stroke premix)
Transmission Oil Spec:
Yamaha Gear Oil, SAE 10W-30 or equivalent (Specifics in manual)
Coolant Type:
High-quality ethylene glycol-based coolant, mixed 50/50 with distilled water (Specifics in manual)
Brake Fluid Type:
DOT 4 hydraulic brake fluid (Specifics in manual)
Common Wear Items:
Piston rings, clutch plates, chain and sprockets, wheel bearings, fork seals, brake pads.
Potential Performance Issues:
Carburetor jetting sensitivity to altitude/temperature, wear in the powervalve mechanism affecting performance, clutch slippage if not maintained.
Suspension Maintenance:
Regular fork oil changes and seal replacements are crucial for maintaining optimal performance.
Yamaha Motorsports:
Yamaha has a long and storied history in motocross and off-road racing, consistently producing competitive and innovative machinery.
Yz85 Development:
The YZ85 has been a staple in Yamaha's junior motocross lineup, evolving with chassis and engine improvements to maintain competitiveness.
Generation Details:
The 2007-2011 models represent a specific generation of the YZ85, likely featuring refined suspension, engine tuning, and styling updates over earlier models.
Manufacturing Location:
Likely manufactured in Japan or other Yamaha global facilities (specifics in manual or VIN data)
Sales Figures:
Sales data not publicly available, but the YZ85 is a consistent seller in the youth motocross market.
