The Yamaha XS400, produced from 1977 through 1982, represents a significant offering in the mid-weight parallel-twin motorcycle segment. Known for its balanced performance and everyday usability, the XS400 series, encompassing models like the XS400G, H, J, K, SH, SJ, and SK, was engineered to provide a reliable and enjoyable riding experience. Its air-cooled, 4-stroke, DOHC parallel-twin engine, typically displacing around 392 cc, delivered approximately 35-45 horsepower, making it a capable machine for both commuting and spirited riding. The model was recognized for its general reliability and smooth engine operation, positioning it as a strong competitor against other offerings from Honda, Kawasaki, and Suzuki during its era.
This comprehensive service repair manual is designed to assist professional technicians and experienced DIY mechanics in maintaining and repairing the Yamaha XS400. It covers a wide array of systems, including detailed procedures for engine disassembly, assembly, tuning, lubrication, cooling, ignition, and fuel systems, as well as drivetrain components like the clutch and transmission. Furthermore, the manual provides in-depth guidance on chassis elements such as suspension and brakes, electrical systems, and bodywork. With clear, step-by-step instructions, diagnostic procedures, and extensive technical specifications, this manual serves as an indispensable resource for all repair, maintenance, rebuild, and restoration needs for your XS400.
Production Years Covered:
1977, 1978, 1979, 1980, 1981, 1982
Model Code Range:
XS400G, XS400H, XS400J, XS400K, XS400SH, XS400SJ, XS400SK (Specific codes may vary by market and sub-model)
Market Niche:
Sportbike/Standard Motorcycle for its era, popular for its balance of performance and everyday usability.
Key Competitors:
Honda CB550/CB650, Kawasaki KZ550/KZ650, Suzuki GS550/GS650.
Manual Benefits:
Empowers owners and technicians with comprehensive, detailed information for all repair and maintenance needs, mirroring professional technician resources.
Manual Presentation:
Structured with numbered steps, notes, cautions, warnings, and clear figure references for ease of use.
Manual Type:
Full Service Repair Manual
Primary Coverage:
Repair, Maintenance, Rebuild, Refurbish, Restoration
Estimated Page Count:
Refer to individual manual; typically 200-500+ pages for comprehensive coverage.
Intended Audience:
Professional Technicians and Experienced DIY Mechanics
File Format:
PDF (Portable Document Format)
Engine Systems:
Engine disassembly, assembly, tuning, lubrication, cooling system, ignition system, fuel system (carburetors), exhaust system.
Drivetrain Systems:
Clutch, transmission, final drive (chain and sprocket), gearbox overhaul.
Chassis Systems:
Frame, front suspension (forks), rear suspension (shocks/swingarm), steering system, wheels, brakes (front and rear).
Electrical Systems:
Wiring diagrams, lighting system, starting system, charging system, battery, ignition coil, starter motor, switches.
Bodywork And Trim:
Body panels, fuel tank, seat, fenders, handlebars, controls, instruments, trim components.
Maintenance Procedures:
Oil changes, filter replacements, spark plug inspection/replacement, chain adjustment, brake fluid changes, carburetor synchronization.
Diagnostic Procedures:
Troubleshooting common problems, electrical fault finding, carburetor performance diagnosis.
Repair Procedures:
Detailed step-by-step instructions for component removal, installation, and repair.
Rebuild Procedures:
Comprehensive instructions for engine and transmission overhauls.
Depth Of Coverage:
Detailed, encompassing everything from routine maintenance to complete engine and transmission rebuilds.
Print Quality:
Full Printable (High Resolution for clear printing)
Binding Type:
Digital (PDF - Printable)
Paper Type Equivalent:
N/A (Digital format)
Delivery Method:
Instant Download
Required Software:
Adobe PDF Reader, WinRAR (for potential archive extraction)
Operating Systems:
All Versions of Windows & Mac
Engine Type:
Air-cooled, 4-stroke, DOHC, Parallel-Twin
Displacement:
392 cc (approx.)
Bore X Stroke:
69.0 mm x 51.4 mm (typical for early models)
Compression Ratio:
9.2:1 (typical)
Horsepower:
Approximately 35-45 HP @ 8000-9000 RPM (varies by year and specific model tune)
Torque:
Approximately 30-35 Nm @ 6000-7000 RPM (varies by year and specific model tune)
Carburetor Type:
Dual Mikuni VM34 or similar constant velocity carburetors
Fuel Capacity:
Approximately 12-15 Liters (varies by model)
Ignition Type:
Electronic Ignition (CDI) or TCI depending on the specific year
Transmission Type:
6-speed, constant mesh
Clutch Type:
Wet, multi-plate
Dry Weight:
Approximately 170-180 kg (varies by model)
Overall Length:
Approximately 2100-2200 mm (varies by model)
Overall Width:
Approximately 750-850 mm (varies by model)
Wheelbase:
Approximately 1400-1450 mm (varies by model)
Seat Height:
Approximately 780-800 mm (varies by model)
Braking System Front:
Single Disc Brake (some later models may have dual discs)
Braking System Rear:
Drum Brake
Frame Type:
Steel Double Cradle Frame
Lighting:
Halogen Headlight, LED/Incandescent Tail and Turn Signals
Instrumentation:
Analog speedometer, tachometer, odometer, trip meter, neutral indicator, oil pressure warning light, high beam indicator.
Charging System:
Alternator with external regulator (or internal on later models).
Oil Change Interval:
Typically every 3,000-5,000 km or 6-12 months (refer to manual for specific mileage/time).
Valve Clearance Check Interval:
Typically every 6,000-10,000 km (crucial for engine longevity).
Spark Plug Replacement Interval:
Inspect every 5,000 km, replace as needed or every 10,000-15,000 km.
Engine Oil Type:
Yamalube or equivalent motorcycle-specific 10W-40 or 20W-50 API SE, SF, or SG (check manual for exact viscosity and API rating).
Engine Oil Capacity:
Approximately 2.0-2.5 Liters (with filter change, check manual).
Brake Fluid Type:
DOT 3 or DOT 4 (check manual, typically replaced every 2 years).
Fork Oil Type:
Yamalube Fork Oil or equivalent SAE 10W (check manual for specific weight and quantity).
Common Wear Items:
Carburetor diaphragm wear, aging electrical connectors, worn fork seals, cam chain tensioner wear.
Typical Maintenance Challenges:
Carburetor synchronization can be finicky, some electrical components may require cleaning or replacement due to age, valve adjustments require care.
Yamaha Motorcycle History:
Yamaha Motor Company, established in 1955, has a rich history in motorcycle manufacturing, known for innovation and performance across various segments.
Xs400 Genesis:
The XS400 was introduced as Yamaha's offering in the mid-weight parallel-twin segment, aiming to provide a balance of sporty performance and everyday practicality.
Xs400 Variants:
The XS400 line saw several iterations within this period, including standard models, 'Special' versions with custom styling (e.g., spoke wheels, different handlebars), and minor engine tuning adjustments across the years.
Manufacturing Location:
Japan
Industry Reputation:
The XS400 was generally well-regarded for its reliability, smooth engine operation, and balanced handling for its class during its production run.
