Vehicle Segment:
Mid-size, parallel-twin cylinder motorcycle, popular for commuting and light touring in its era
Target Audience Manual:
DIY mechanics, restoration enthusiasts, professional motorcycle technicians
Competitors Era:
Honda CB400 series, Yamaha RD400, Suzuki GS400, Kawasaki KZ440 (later)
Engine Configuration:
Parallel-twin, air-cooled, 4-stroke
Design Philosophy:
Balanced performance, reliability, and styling for the 400cc class
Value Proposition:
Provides essential knowledge for maintaining and repairing the KZ400, saving time and money
Completeness:
Offers a complete guide, distinguishing it from basic owner's manuals
Engine:
Engine assembly, disassembly, tuning, troubleshooting, specific component repair (e.g., carburetors, ignition, cooling)
Transmission:
Gearbox, clutch, shift mechanism, lubrication
Drivetrain:
Chain drive, sprockets, rear axle assembly
Chassis:
Frame, suspension (front forks, rear shocks), steering assembly
Brakes:
Front disc brake system, rear drum brake system, hydraulic lines, master cylinder, calipers, linkage
Electrical:
Wiring diagrams, battery, charging system (alternator/stator, regulator/rectifier), ignition system (points, CDI), lighting, instrumentation, starter motor
Fuel System:
Fuel tank, petcock, fuel lines, carburetors (Mikuni VM series typical)
Exhaust System:
Exhaust pipes, mufflers, mounting hardware
Bodywork And Trim:
Fenders, side covers, seat, fuel tank, handlebars, controls, decals
Routine Maintenance:
Oil changes, filter replacement, chain adjustment, spark plug service, brake checks, tire pressure
Troubleshooting:
Systematic diagnosis of common problems, electrical fault finding
Engine Rebuild:
Top-end overhaul (cylinder head, pistons), bottom-end service (crankshaft, bearings), valve adjustment
Carburetor Service:
Disassembly, cleaning, rebuilding, synchronization, jetting adjustments
Electrical Repair:
Component testing, wiring harness repair, charging system diagnosis
Brake Overhaul:
Calibrating drum brakes, servicing disc brake calipers and master cylinders
Suspension Service:
Fork oil changes, seal replacement, rear shock adjustment/replacement
Steering Head Service:
Bearing adjustment and replacement
Depth Level:
Comprehensive, covering basic maintenance to full engine and component rebuilds
Diagnostic Capabilities:
Detailed troubleshooting guides and symptom-based diagnostics
Specifications Detail:
Includes critical torque values, clearances, fluid capacities, and electrical specifications
Engine Type:
Air-cooled, four-stroke, parallel-twin
Displacement:
398 cc (24.3 cu in)
Bore X Stroke:
66.0 mm x 58.0 mm (2.60 in x 2.28 in)
Compression Ratio:
9.0:1 (typical)
Valve Train:
SOHC, 2 valves per cylinder
Horsepower:
Approx. 34-38 HP @ 8,000 RPM (varies slightly by year/model)
Torque:
Approx. 23-25 lb-ft @ 6,500 RPM (varies slightly by year/model)
Carburetion:
Dual Mikuni VM series carburetors (e.g., VM24 or VM26)
Fuel Capacity:
Approx. 12-14 Liters (3.2-3.7 US gal)
Ignition Type:
Battery Coil Ignition (BCI) or CDI (Capacitor Discharge Ignition) depending on year/market
Oil Capacity:
Approx. 2.5 Liters (2.6 US qt) with filter change
Oil Type Specification:
SAE 10W-40 or 20W-40 motorcycle oil API SE or SF rated (consult manual for precise recommendation)
Oil Change Interval:
Every 2,000-3,000 km (1,200-1,800 miles) or 3-6 months (refer to manual for exact mileage/time)
Valve Adjustment Interval:
Every 6,000-10,000 km (3,700-6,200 miles) or annually
Spark Plug Replacement:
Every 6,000-12,000 km (3,700-7,500 miles), depending on plug type and condition
Chain Lubrication Adjustment:
Lubricate every 500-1,000 km (300-600 miles), adjust slack every 2,000 km (1,200 miles)
Engine Oil Grade:
10W-40 or 20W-40
Brake Fluid Type:
DOT 3 or DOT 4 (consult manual for precise type)
Fork Oil Type:
Specific weight oil (e.g., 10W) as recommended in the manual
Carburetor Performance:
Can be prone to fuel mixture issues, float bowl leaks, or jet clogging due to age.
Ignition System:
Points ignition (on earlier models) can require frequent adjustment; CDI components may degrade over time.
Charging System:
Regulator/rectifier failures can lead to battery overcharging or undercharging.
Exhaust Leaks:
Gasket failures at the cylinder head or muffler joints can cause exhaust leaks.
Typical Repairs:
Carburetor rebuild, clutch replacement, front fork seal replacement, brake system servicing.
Kawasaki Motorcycles:
Kawasaki Heavy Industries has a long history of manufacturing motorcycles, known for performance and reliability.
Kz Series Introduction:
The KZ400 was part of Kawasaki's successful KZ line, which offered a range of parallel-twin and four-cylinder motorcycles.
Kz400 Development:
Introduced as a middleweight option, it offered a good balance of performance and economy, competing in a popular segment.
Kz400D Vs S:
The KZ400D was the standard model, while the KZ400S (Special/Custom) often featured cosmetic differences like different handlebars, exhaust, or a smaller fuel tank, and sometimes spoke wheels.
Production Period:
1974-1977
Manufacturing Location:
Primarily Japan
