The Yamaha R5C, produced in 1972 and 1973, represents a performance-oriented, air-cooled, two-stroke parallel-twin motorcycle that emphasized lightweight design and spirited acceleration. This model reflects the engineering and styling prevalent in Japanese motorcycles of the early 1970s, competing with similar displacement offerings from other major manufacturers. Its design focused on delivering a dynamic riding experience, characteristic of Yamaha's early reputation for high-performance two-stroke engines. This comprehensive workshop service manual provides detailed guidance for the maintenance and repair of the Yamaha R5C. It covers essential systems including the engine, transmission, chassis, electrical components, and bodywork. The manual includes step-by-step repair instructions, routine maintenance procedures, troubleshooting guidance for common issues, and critical technical specifications such as torque settings and fluid capacities. This resource is designed to assist owners and technicians in keeping the R5C in optimal working condition. 🏷️ Basic Information Identification Make: Yamaha Model: R5C Year: 1972, 1973 Codes Model Code: R5C 👋 Introduction Market Position Positioning: Performance-oriented twin-cylinder motorcycle of its era, targeted at enthusiasts and riders seeking spirited performance. Competitive Analysis Competitors: Competed with other 350cc to 400cc two-stroke motorcycles from manufacturers like Kawasaki, Suzuki, and Honda. Key Features Engine Type: Air-cooled, two-stroke, parallel-twin Performance Focus: Emphasis on lightweight design and strong acceleration characteristic of two-stroke engines. Design Era: Reflects the styling and engineering prevalent in Japanese motorcycles of the early 1970s. 📋 Manual Details Coverage Areas Coverage Type: Comprehensive Workshop Repair & Service Page Count Pages: 113 Manual Type Type: Workshop Service Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Engine assembly, disassembly, tuning, lubrication, cooling, fuel, ignition, exhaust Transmission: Clutch, gearbox operation, maintenance, troubleshooting Chassis: Frame, suspension (front and rear), steering, wheels, tires, brakes (front and rear drum) Electrical: Lighting system, ignition system, charging system, wiring diagrams, battery, instrumentation Bodywork: Body panels, fuel tank, seat, handlebars, fenders Procedures Included Maintenance: Routine maintenance, oil changes, filter replacements, chain adjustment, spark plug service Troubleshooting: Diagnostic procedures for common mechanical and electrical issues Repair: Detailed step-by-step instructions for component disassembly, repair, and reassembly Specifications: Torque specifications, clearances, fluid capacities, electrical resistance values Technical Depth Depth: Designed for mechanical technicians, covering in-depth repairs and diagnostics 📊 Manual Specifications File Format Format: Digital (PDF) Print Quality Quality: High-resolution scans suitable for printing Binding Type Binding: N/A (Digital Download) Paper Type Paper: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: Two-stroke, air-cooled, parallel-twin Displacement: 347 cc (21.18 cubic inches) Bore X Stroke: 54.0 mm x 74.0 mm (2.13 in x 2.91 in) Compression Ratio: 6.8:1 Carburetion: Two (2) Mikuni VM30SC carburetors Ignition: CDI (Capacitor Discharge Ignition) Performance Horsepower: Approximately 33 HP @ 7,500 RPM (Manufacturer claimed) Torque: Not explicitly stated, but characteristic of its class for the era. Fuel System Fuel Type: Unleaded gasoline with 2-stroke oil mixture (e.g., 50:1 or 32:1 depending on oil quality and manufacturer recommendation). Fuel Tank Capacity: Approx. 2.6 US gallons (9.8 Liters) 🔧 Transmission Standard Type: Constant mesh, 5-speed Clutch: Wet, multiple disc Features Drive Type: Chain drive 📐 Dimensions Exterior Overall Length: Approx. 82.3 inches (2090 mm) Overall Width: Approx. 31.7 inches (805 mm) Overall Height: Approx. 46.3 inches (1175 mm) Weights Dry Weight: Approx. 348 lbs (158 kg) Wet Weight: Not explicitly specified, but would include oil, fuel, and battery weight. 🛡️ Safety Features Ratings Safety Standards: No formal crash ratings or safety certifications like modern vehicles; safety relied on rider skill and mechanical integrity. Active Features Brakes: Front and Rear Drum Brakes. Mechanical actuation via cables. Passive Features Lighting: Headlight, taillight, brake light, turn signals (depending on market specification). Frame Construction: Steel cradle frame designed for rigidity and handling. 💡 Technology Features Infotainment Features: N/A. This is a vintage motorcycle; technology features are limited to essential functions. Driver Assistance Features: N/A. No driver assistance systems. Connectivity Features: N/A. No electronic connectivity features. 🔧 Maintenance Service Intervals Oil Change: Refer to manual for specific engine oil change intervals based on mileage or operating hours. Typically every 2,000-3,000 miles or annually. Spark Plug: Regular inspection and cleaning/replacement recommended based on mileage (e.g., every 1,000-2,000 miles). Chain Maintenance: Frequent lubrication and tension adjustment is critical for longevity and performance. Fluid Specifications Engine Oil Type: Specific 2-stroke pre-mix oil suitable for air-cooled engines. Manual will specify viscosity and API classification, if applicable. Gearbox Oil: Yamaha Gear Oil 10W-30 or equivalent is commonly recommended for the transmission. Capacity: ~1.2 Liters. Brake Fluid: Not applicable, as drum brakes are mechanically actuated. Cable lubrication is required. Known Issues Two Stroke Wear: Typical for vintage two-strokes: piston ring wear, cylinder scoring, carbon buildup in ports and exhaust, reed valve wear. Carburetor: Carburetors (Mikuni VM30SC) can be prone to clogging, worn jets, and float issues if not maintained. Electrical System: Aging wiring harnesses, corroded connectors, and failing stator or rectifier can cause electrical gremlins. Clutch...