The 1988 NT650 is a mid-size sport touring motorcycle featuring a 647cc liquid-cooled V-twin engine, 6-speed transmission, hydraulic disc brakes front and rear, tubular steel frame, and comprehensive instrumentation. This service manual covers maintenance procedures, specifications, troubleshooting, and repair instructions for all major systems including engine, transmission, electrical, brakes, suspension, and chassis components.
Overview of the 1988 NT650 motorcycle and service manual organization.
| Component | Description |
|---|---|
| Model Identification | NT650 V-twin sport touring motorcycle |
| Frame Number Location | Stamped on steering head |
| Engine Number Location | Stamped on crankcase left side |
| Manual Organization | System-based chapters with step-by-step procedures |
| Safety Precautions | Required personal protective equipment and workshop safety |
| Tool Requirements | Standard metric tools and special service tools |
| Service Intervals | Regular maintenance schedule and inspection points |
| Lubrication Points | All grease fittings and lubrication requirements |
| Torque Specifications | Critical fastener torque values throughout motorcycle |
| Diagnostic Procedures | Systematic troubleshooting approach for all systems |
Regular maintenance intervals and service requirements.
WARNING! Failure to perform regular maintenance may void warranty and compromise safety. Always use genuine parts.
Complete engine maintenance and repair procedures.
CAUTION! Engine components are precision parts; handle with care and use proper tools.
Carburetor service and fuel system maintenance.
Carburetor Specifications: Dual CV carburetors, 34mm venturi.
Main Jet: #112, Pilot Jet: #38, Needle Jet: 4th position, Float Height: 12.5mm, Idle Speed: 1200 ± 100 rpm, Fuel Tank Capacity: 18 liters (4.8 gallons). Synchronization: Use vacuum gauges for carburetor balance. Fuel Filter: Replace every 12,000 miles. Throttle Cables: Lubricate every 4,000 miles, adjust free play to 2-3mm.
Complete electrical system diagnosis and repair.
Tip: Always disconnect battery before performing electrical work to prevent shorts.
Hydraulic disc brake service and maintenance.
WARNING! Brakes are critical safety components; always test thoroughly after service.
Front fork and rear shock service procedures.
Front Suspension: 41mm conventional forks, travel 140mm. Spring Rate: 0.70 kg/mm. Oil Capacity: 486ml per leg, 10W oil. Rear Suspension: Single shock with adjustable preload. Wheel Alignment: Check and adjust as needed. Steering Head Bearings: Tapered roller bearings, adjustment procedure. Swingarm Bearings: Inspection and lubrication schedule.
Frame, wheels, and body component service.
CAUTION! Use proper lifting equipment; motorcycle weighs 198 kg (436 lbs).
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | Fuel, spark, compression | Check fuel flow, spark plugs, compression test. |
| Poor idle | Carburetor sync, vacuum leaks | Synchronize carburetors, check for vacuum leaks. |
| Electrical failure | Battery, charging system | Test battery voltage, check stator output. |
| Brake drag | Calipers, master cylinder | Clean and lubricate caliper pins, check master cylinder. |
| Transmission slipping | Clutch adjustment, worn plates | Adjust clutch cable, inspect clutch plates. |
| Overheating | Coolant, thermostat | Check coolant level, test thermostat operation. |
| Oil consumption | Piston rings, valve seals | Compression test, inspect valve seals. |
| Vibration | Engine mounts, wheel balance | Check engine mounts, balance wheels. |
Diagnostic Tools: Multimeter, compression tester, vacuum gauges required.