Segment:
High-performance sport ATV
Target Audience:
Enthusiasts, recreational riders, racers, and DIY mechanics seeking in-depth technical knowledge for maintenance and repair.
Competitors:
Honda TRX450R, Suzuki LT-R450, Kawasaki KFX450R.
Atv Highlight:
Renowned for its powerful engine and capable chassis, a popular choice for trail riding and recreational off-roading during its production run.
Manual Value Proposition:
Provides factory-level diagnostic and repair procedures, essential for maintaining optimal performance and longevity of the YFM660R.
Engine:
Complete overhaul, disassembly, assembly, tuning, diagnostics, lubrication, cooling system, fuel system (carburetor), ignition system, exhaust system.
Transmission:
Clutch (wet multi-plate), gearbox, drive shaft, final drive (chain drive), disassembly, assembly, adjustment, lubrication.
Chassis:
Frame, suspension (front and rear, including shocks and linkages), steering system, wheel bearings, hubs, brake systems (front and rear discs).
Electrical System:
Wiring diagrams, battery, charging system (stator, regulator/rectifier), lighting, ignition system components (CDI, spark plug), starter motor, instrumentation.
Body And Trim:
Body panels, fenders, seat, handlebars, controls, footpegs, graphics.
Maintenance:
Regular inspections, oil changes, filter replacements, chain maintenance, brake checks, carburetor cleaning and adjustment, valve clearance checks and adjustment, spark plug replacement.
Troubleshooting:
Diagnostic charts, common problems and their solutions, electrical system diagnostics, engine performance issues.
Repair And Rebuild:
Step-by-step instructions for major component overhauls, engine rebuilds, transmission repair, suspension component replacement, brake caliper servicing.
Technical Specifications:
Torque specifications, clearances, fluid capacities, electrical resistance values, engine timing, carburetor jetting.
Depth:
Comprehensive: Covers everything from basic maintenance to full engine and transmission rebuilds. Includes detailed diagrams, exploded views, and diagnostic procedures.
Engine Type:
Four-stroke, SOHC, 5-valve, liquid-cooled
Bore X Stroke:
100.0 mm x 83.9 mm
Starting System:
Electric Start
Horsepower Estimate:
Approximately 50-55 hp (factory figures often understated)
Torque Estimate:
Approximately 45-50 lb-ft
Carburetor:
Mikuni BSR42, single, flat-slide
Fuel Type:
Unleaded gasoline, minimum 87 octane
Oil Type:
Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher, JASO MA certified.
Oil Capacity With Filter Change:
2.40 L (2.5 US qt)
Oil Capacity Without Filter Change:
2.10 L (2.2 US qt)
Coolant Type:
Permanent antifreeze, mixture of 50% ethylene glycol and 50% deionized water
Coolant Capacity:
1.50 L (1.6 US qt)
Type:
5-speed constant mesh, manual clutch
Clutch Type:
Wet, multi-plate
Final Drive:
O-ring sealed chain
Gear Ratios:
Detailed in manual (1st: 2.615, 2nd: 1.944, 3rd: 1.556, 4th: 1.292, 5th: 1.045)
Fluid Type:
Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher, JASO MA certified.
Fluid Capacity:
0.90 L (0.95 US qt)
Crash Test Information:
Not applicable for ATVs as per automotive standards.
Brakes:
Front: Dual hydraulic disc. Rear: Single hydraulic disc.
Parking Brake:
Mechanical disc brake (rear caliper lever lock)
Handlebars:
Wide handlebars for control and leverage.
Footpegs:
Aggressive, serrated footpegs for grip.
Infotainment System:
N/A (Basic instrumentation only)
Driver Assistance Features:
N/A
Connectivity Features:
N/A
Instrument Panel:
Digital speedometer, odometer, trip meter, neutral indicator, reverse indicator, oil warning light, coolant temperature warning light, neutral indicator.
Engine Oil Change:
Every 1,000 km (600 miles) or 6 months (whichever comes first), or more frequently for hard use.
Air Filter Cleaning:
Every 100 km (60 miles) or monthly; replace as needed.
Spark Plug Replacement:
Every 3,000 km (1,800 miles) or 12 months.
Valve Clearance Check:
Every 3,000 km (1,800 miles) or 12 months.
Chain Lubrication And Adjustment:
Every 500 km (300 miles) or monthly; inspect more frequently.
Engine Oil Specification:
Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher, JASO MA certified.
Transmission Oil Specification:
Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher, JASO MA certified.
Coolant Specification:
50% ethylene glycol and 50% deionized water.
Brake Fluid Specification:
DOT 3 or DOT 4 hydraulic brake fluid.
Common Wear Items:
Clutch plates, wheel bearings, tie rod ends, swingarm bushings, front suspension bushings, brake pads.
Carburetor Tuning:
Can require periodic adjustments due to altitude or temperature changes, and jetting may need modification for aftermarket exhaust systems.
Engine Performance Tips:
Regular cleaning of the carburetor and air filter, and proper valve adjustments are critical for maintaining the 660cc engine's robust performance.
