Segment:
Maxi-scooter segment
Target Audience:
Commuters seeking comfort, practicality, and performance; owners and independent repair shops.
Competitors:
Suzuki Burgman 400, Honda Silver Wing (not a direct 400cc competitor, but in the maxi-scooter class), Aprilia Scarabeo 500.
Distinctive Features:
Comfortable riding position, ample under-seat storage, powerful 400cc engine for highway use.
Manual Advantage:
Provides the essential technical data for maintaining and repairing this specific maxi-scooter model.
General Information:
Covers general guidelines, safety precautions, and vehicle identification.
Specifications:
Detailed technical specifications for all vehicle components and systems.
Periodic Checks And Adjustments:
Procedures for routine inspections and adjustments to maintain optimal performance.
Chassis:
Covers frame, suspension (front and rear forks, shock absorber), steering, wheels, and brakes.
Engine:
Comprehensive coverage of the 400cc engine, including disassembly, assembly, and component details.
Cooling System:
Details on the liquid cooling system, including radiator, coolant, and pump maintenance.
Fuel Injection System:
In-depth coverage of the electronic fuel injection (EFI) system, including sensors, injectors, and ECU.
Electrical System:
Extensive coverage of the electrical system, including battery, charging system, ignition, lighting, and wiring diagrams.
Troubleshooting:
Diagnostic procedures and solutions for common and uncommon issues.
Maintenance:
Scheduled maintenance, fluid changes, filter replacements, spark plug service, and general upkeep.
Repair:
Step-by-step repair instructions for all major components and systems.
Diagnostics:
Detailed troubleshooting guides and diagnostic fault codes (if applicable).
Rebuilds:
Complete engine and transmission rebuild procedures with torque specifications.
Depth:
Factory-level detail suitable for professional technicians and advanced DIY mechanics.
Diagrams:
Includes hundreds of detailed diagrams, schematics, and illustrations.
Accuracy:
Original manufacturer-written content ensuring the highest level of accuracy and completeness.
Engine Type:
4-stroke, liquid-cooled, SOHC, 4-valve
Displacement:
395 cc (24.1 cubic inches)
Bore X Stroke:
92.0 mm x 75.0 mm (3.62 in x 2.95 in)
Compression Ratio:
11.6:1
Horsepower Est Rpm:
Approx. 20.7 kW (27.8 hp) @ 7500 rpm (Manufacturer specified range might vary)
Torque Est Rpm:
Approx. 30.3 Nm (22.4 lb-ft) @ 6250 rpm (Manufacturer specified range might vary)
Fuel Delivery:
Electronic Fuel Injection (EFI)
Fuel Type:
Unleaded gasoline
Oil Type:
Yamalube Performance 4-stroke Motorcycle Oil (or equivalent API SG or higher, SAE 10W-40 recommended)
Oil Capacity:
Approx. 1.7 L (1.8 US qt) without filter change, 1.9 L (2.0 US qt) with filter change
Ignition System:
Digital TCI (Transistor Controlled Ignition)
Spark Plug Type:
CR9E (NGK) or similar
Valve Clearance Intake:
0.09-0.13 mm (cold)
Valve Clearance Exhaust:
0.17-0.21 mm (cold)
Crash Test Ratings:
N/A (Motorcycles/Scooters typically do not undergo standardized car crash testing; safety is assessed through design and active safety features).
Brakes Front:
Dual hydraulic disc brakes (specific diameter typically detailed in manual)
Brakes Rear:
Hydraulic disc brake (specific diameter typically detailed in manual)
Lighting:
Halogen headlights, LED taillight, turn signals.
Frame Construction:
Steel tube frame for rigidity and stability.
Windscreen:
Adjustable or fixed windscreen for rider protection.
Dashboard:
Analog speedometer and tachometer, digital odometer, fuel gauge, coolant temperature gauge, and indicator lights.
ABS:
ABS was not standard on all 2004 models but may have been an option or standard on specific sub-models (manual would clarify).
Charging Port:
Accessory power outlet may be present for charging devices (details in manual).
First Service:
Typically around 600 miles (1,000 km) for initial inspection and oil change.
Regular Oil Change:
Every 2,000-4,000 miles (3,000-6,000 km) or as per manual recommendation.
Air Filter Replacement:
Inspect every 2,000 miles (3,000 km), replace as needed or at specified intervals (e.g., 8,000-12,000 miles).
Spark Plug Replacement:
Replace every 6,000-8,000 miles (10,000-12,000 km) or as indicated by wear.
Cv Belt Inspection Replacement:
Inspect at specified intervals (e.g., 4,000 miles), replace generally between 12,000-24,000 miles depending on wear.
Coolant Type:
Yamaha Yamalube Coolant (or equivalent ethylene glycol-based antifreeze with corrosion inhibitors), mixed 50/50 with distilled water.
Brake Fluid Type:
DOT 4 hydraulic brake fluid.
Common Wear Items:
CVT belt, tires, brake pads, battery, and exhaust system are common wear items.
Potential Issues:
While generally reliable, like any vehicle, issues can arise with fuel injectors, cooling system leaks, or electrical connectors if not maintained.
Heritage:
Yamaha Motor Company is a globally recognized manufacturer of motorcycles, marine products, and musical instruments, known for innovation and quality.
Majesty Lineage:
The Majesty line has a history of producing comfortable, large-displacement scooters aimed at touring and commuting.
Yp400 Introduction:
The YP400 Majesty was introduced to offer a balance of performance and economy in the maxi-scooter market.
Manufacturing Location:
Likely manufactured in Japan or Southeast Asia by Yamaha Motor Co., Ltd.
