Target Audience:
Honda NSR125F-R owners, mechanics, and enthusiasts performing maintenance and repairs.
Value Proposition:
Provides factory-level diagnostic and repair information for a classic performance motorcycle.
Manual Type Comparison:
Factory service manual offers more detail and accuracy than aftermarket generic guides.
Authenticity:
Genuine factory service manual content.
Completeness:
Covers all systems, maintenance, and repairs for the specified model range.
Visual Content:
Extensive use of photos and diagrams for clarity.
Engine:
Complete engine disassembly, assembly, tuning, and troubleshooting.
Fuel System:
Carburetor overhaul, fuel pump operation, fuel lines, and tank maintenance.
Ignition System:
CDI unit, spark plug specifications, timing adjustments, and troubleshooting.
Cooling System:
Radiator, fan operation, coolant specifications, and bleeding procedures.
Transmission:
Clutch operation, gear selection, gearbox disassembly and reassembly, and lubricant specifications.
Suspension:
Front fork overhaul, rear shock absorber service, spring rates, and damping adjustments.
Brakes:
Hydraulic brake system service, caliper maintenance, master cylinder overhaul, pad replacement, and fluid specifications.
Electrical System:
Wiring diagrams, lighting system, charging system, battery maintenance, starter motor, and component testing.
Bodywork And Frame:
Fairing removal and installation, seat, fuel tank, and frame inspection.
Maintenance:
Regular scheduled maintenance, oil changes, filter replacements, chain adjustment, and general upkeep.
Troubleshooting:
Diagnostic charts for common problems, electrical and mechanical fault finding.
Repair:
Step-by-step instructions for component repair and replacement.
Disassembly Reassembly:
Detailed instructions for complete breakdown and rebuilding of all major systems.
Depth Level:
Comprehensive (from basic maintenance to advanced diagnostics and rebuilds).
Diagnostic Capability:
Detailed troubleshooting guides with symptom-based diagnosis.
Visual Aids:
Hundreds of photos and illustrations.
Electrical Diagrams:
Complete wiring diagrams for all circuits.
Engine Type:
Liquid-cooled, 2-stroke, single-cylinder
Bore X Stroke:
54.0 mm x 54.5 mm (typical for JC20)
Compression Ratio:
7.2:1 (typical for JC20)
Power Output:
Approx. 26.5 HP @ 11,000 RPM (for European models)
Torque:
Approx. 17.5 Nm @ 10,500 RPM (for European models)
Carburetor:
Keihin PE28 (typical for JC20)
Ignition:
Digital CDI with electronic advance
Fuel Type:
Unleaded gasoline (91-98 octane recommended)
Fuel Tank Capacity:
Approx. 12 Liters (including reserve)
Oil Mixing:
Automatic oil injection system
2-Stroke Oil Spec:
JASO FC or FD certified 2-stroke motorcycle oil
Safety Ratings:
Motorcycle safety standards for the era; specific crash test data not applicable like cars.
Braking System:
Front: Hydraulic disc; Rear: Hydraulic disc
Tire Sizes:
Front: 100/80-17; Rear: 130/70-17 (typical)
Lighting:
Halogen headlight, LED taillight, incandescent indicators.
Oil Change Interval:
Refer to manual for specific mileage/time recommendations (typically 3,000-5,000 km).
Spark Plug Replacement:
Refer to manual for specific intervals (e.g., 5,000-10,000 km).
Air Filter Cleaning Replacement:
Refer to manual for specific intervals based on riding conditions.
Chain Lubrication Adjustment:
Regularly, and adjustment based on slack specification (refer to manual).
Engine Oil:
Not applicable (2-stroke, uses pre-mix or oil injection).
Cooling System Coolant:
Honda Type 2 Coolant or equivalent ethylene glycol based coolant (50% mixture with distilled water).
Brake Fluid:
DOT 3 or DOT 4 hydraulic brake fluid.
2 Stroke Oil:
JASO FC or FD certified 2-stroke motorcycle oil.
Common Wear Items:
Piston rings, clutch plates, fork seals, exhaust packing, and ignition components.
2 Stroke Specific Concerns:
Carbon build-up in exhaust and cylinder head, potential power valve issues if not maintained.
Electrical Issues:
Corrosion on connectors, regulator/rectifier failure (typical for older bikes).
Brand Focus:
Honda is renowned for its engineering excellence, reliability, and performance in motorcycles.
Nsr Lineage:
The NSR series is a legendary line of performance-oriented 2-stroke sportbikes, inspired by Honda's Grand Prix racing machines.
Jc20 Designation:
The JC20 is a key iteration of the NSR125, popular for its performance and handling.
Manufacturing Location:
Japan (primarily)
Model Recognition:
The NSR125F-R is highly regarded in the 125cc sportbike category for its performance and racing heritage.
Performance Ratings:
Consistently praised in period reviews for its handling, acceleration, and rev-happy engine.
Certification Standards:
Complies with all relevant emissions and safety certifications for its production years and markets.
