Target Audience:
Enthusiasts and mechanics working on the 1980 Yamaha XS650G/SG models.
Value Proposition:
The definitive resource for maintaining, troubleshooting, and repairing the Yamaha XS650G/SG, ensuring longevity and optimal performance.
Manual Type Advantage:
Official factory manual provides accurate and complete technical data often missing in aftermarket guides.
Completeness:
Provides the complete factory service information, covering all aspects of the motorcycle.
Usability:
Digital PDF format allows for easy searching, printing of specific sections, and digital access.
Engine:
Detailed coverage of the 653cc parallel-twin engine, including disassembly, assembly, tuning, and troubleshooting.
Fuel System:
Comprehensive coverage of the Mikuni VM34 carburettors, fuel pump, and fuel lines.
Ignition System:
Detailed information on the electronic ignition system, including ignition timing and component testing.
Transmission:
Coverage of the 5-speed constant mesh transmission, clutch operation, and gearbox disassembly/assembly.
Drivetrain:
Detailed instructions for maintenance and repair of the final drive system (chain drive).
Frame And Suspension:
Information on frame inspection, steering head bearings, front forks (telescopic), and rear suspension (swingarm, shock absorbers).
Brakes:
Comprehensive coverage of front disc brake system and rear drum brake system, including hydraulics and adjustments.
Electrical System:
Extensive details on the entire electrical system, including wiring diagrams, lighting, charging system (alternator, battery), starter motor, and switches.
Wheels And Tires:
Specifications and maintenance procedures for wheels, spokes, and tyre replacement.
Bodywork And Trim:
Information on fuel tank removal, seat, fenders, and other cosmetic components.
Maintenance:
Routine maintenance tasks such as oil changes, filter replacements, chain adjustment, and lubrication.
Troubleshooting:
Systematic diagnostic procedures for common problems and fault finding.
Engine Rebuild:
Step-by-step instructions for complete engine overhaul, including piston, ring, valve, and crankshaft replacement.
Carburetor Tuning:
Detailed guidance on adjusting and synchronizing the VM34 carburetors for optimal performance.
Electrical Diagnostics:
Procedures for diagnosing electrical faults using multimeters and wiring diagrams.
Suspension Adjustment:
Instructions on adjusting front and rear suspension settings.
Brake System Maintenance:
Procedures for brake pad replacement, fluid bleeding, and caliper/drum servicing.
Depth:
Comprehensive, from basic maintenance to full engine and transmission rebuilds.
Diagnostic Level:
Advanced diagnostic information, including troubleshooting charts and electrical schematic interpretation.
Specification Detail:
Detailed torque specifications, clearances, tolerances, and fluid capacities.
Engine Type:
4-stroke, air-cooled, parallel-twin
Displacement:
653 cc (39.8 cubic inches)
Bore X Stroke:
75.0 mm x 74.0 mm (2.95 in x 2.91 in)
Valve Train:
Overhead camshaft (OHC), 2 valves per cylinder
Horsepower Est:
Approx. 50 hp @ 6500 rpm (varies slightly by specific model variant)
Torque Est:
Approx. 37.7 lb-ft @ 5500 rpm (varies slightly by specific model variant)
Carburetor Type:
Twin Mikuni VM34-17 carburetors
Fuel Delivery:
Mechanical fuel pump
Fuel Type:
Unleaded gasoline (Octane rating as per Yamaha recommendations for the era, typically 91 RON or higher)
Safety Ratings:
N/A (Motorcycle of this era did not have standardized crash ratings)
Braking System:
Front disc brake, Rear drum brake.
Lighting:
Halogen headlamp, taillight, brake light, turn signals.
Frame Construction:
Steel tube frame provides structural integrity.
Oil Change Interval:
Every 3,000 km (1,800 miles) or 6 months (refer to manual for precise recommendations).
Spark Plug Replacement:
Every 6,000 km (3,600 miles) or 12 months, inspect and gap more frequently.
Valve Clearance Check:
Every 6,000 km (3,600 miles) or 12 months.
Chain Maintenance:
Lubricate and adjust chain every 1,000 km (600 miles) or as needed, check tension.
Engine Oil Type:
Yamalube 4 (or equivalent) SAE 20W-40 API SE (refer to manual for exact grade and API classification).
Brake Fluid Type:
DOT 3 or DOT 4 (check reservoir cap or manual for specific recommendation).
Starter Clutch Wear:
A common wear item that can lead to starter motor disengagement issues. The manual will cover inspection and replacement procedures.
Charging System Rectifier:
Rectifier/regulator units can fail over time, leading to battery charging problems. Manual details testing and replacement.
Carburetor Performance:
Mikuni VM34 carburetors require precise tuning; vacuum leaks or worn internal parts can affect performance. Manual provides detailed tuning guides.
Crankshaft Bearings:
While generally robust, premature wear can occur with improper maintenance or abuse. Manual covers inspection and overhaul.
Oil Leaks:
Common with older motorcycles, leaks can occur at engine gaskets, seals, and O-rings. Manual provides detailed seal replacement procedures.
Manufacturer Origin:
Yamaha Motor Company, Japan
Brand Focus:
Renowned for performance motorcycles, musical instruments, and marine products.
Xs650 Lineage:
The XS650 series, introduced in 1970, was Yamaha's first large-displacement motorcycle and became a significant global success, known for its characterful parallel-twin engine.
1980 Updates:
The 'G' and 'SG' designations typically represent specific styling or minor technical revisions for the 1980 model year, such as updated graphics, minor ergonomic changes, or component supplier variations.
Production Period:
The XS650 was produced from 1970 to 1983 in various iterations.
Manufacturing Locations:
Primarily manufactured in Japan.
