Segment:
Sport Touring Motorcycle
Target Audience:
Performance-oriented riders seeking comfort for longer distances, with a focus on Italian engineering and V-twin character.
Competitors:
Honda VFR, Yamaha FJR, Kawasaki GTR, BMW R series (e.g., R1100S).
Engine Character:
Desmodromic valve actuation, characteristic L-twin torque delivery, potent performance for its class.
Chassis Suspension:
ST4s featured higher-spec Öhlins suspension and lighter Marchesini wheels, enhancing handling and ride quality.
Design Philosophy:
Blending sportbike performance with touring ergonomics, a hallmark of Ducati's approach to sport-touring.
Engine:
Complete overhaul, disassembly, assembly, tuning, troubleshooting, component identification.
Fuel System:
Fuel injection system, throttle bodies, fuel pump, injectors, fuel pressure regulator, diagnostics.
Ignition Injection:
Ignition timing, ECU mapping, sensor diagnostics (TPS, MAP, Crankshaft position), ignition coil testing.
Brake System:
Front and rear brake calipers, master cylinders, brake lines, fluid bleeding, ABS (if applicable), rotor inspection.
Suspension:
Front fork (Öhlins on ST4s), rear shock absorber, linkage, adjustments, seal replacement, spring rates.
Wheels Tires:
Wheel bearing replacement, tire mounting and balancing, recommended tire pressures, wheel specifications.
Electric System:
Wiring diagrams, component testing, battery, charging system, starter motor, lighting, fuses, relays, ECU diagnostics.
Frame Body:
Frame inspection, bodywork removal and installation, fairings, seat, fuel tank, ergonomics.
Exhaust System:
Exhaust pipe inspection, muffler replacement, catalytic converter (if applicable), lambda sensor.
Maintenance:
Scheduled maintenance, oil changes, filter replacements, chain adjustment, spark plug replacement, valve clearance checks.
Repair:
Engine rebuilds, transmission overhauls, suspension fork rebuilds, brake caliper rebuilds, electrical component replacement.
Troubleshooting:
Diagnostic procedures for common faults, error code interpretation, symptom-based troubleshooting guides.
Installation:
Installation of accessories, bodywork components, and key mechanical parts.
Depth:
Comprehensive, from basic owner maintenance to full engine and transmission rebuilds, including detailed torque specifications and diagnostic procedures.
Engine Type:
Liquid-cooled, 4-stroke, 90° L-twin (Desmodromic valve actuation)
Bore X Stroke:
98 mm x 66 mm
Compression Ratio:
11.5:1 (typical for this engine family)
Valvetrain:
Desmodromic, 4 valves per cylinder
Horsepower Est:
113 hp @ 8500 rpm (ST4), 124 hp @ 8500 rpm (ST4s - approx.)
Torque Est:
94 Nm @ 7000 rpm (ST4), 98 Nm @ 7000 rpm (ST4s - approx.)
Fuel Delivery:
Electronic Fuel Injection (Weber Marelli or similar)
Fuel Type:
Unleaded gasoline, minimum 95 RON
Throttle Body Size:
54 mm (typical)
Safety Standards:
Compliant with relevant European and international motorcycle safety standards for its era.
Braking System:
Dual 320 mm discs with 4-piston calipers (front), Single 245 mm disc with 2-piston caliper (rear). ST4s often featured Brembo components.
ABS:
Optional ABS was available on some models during this period, but not standard on all ST4/ST4s.
Lighting:
Halogen headlamp, LED taillight, turn signals.
Dashboard:
Analog tachometer, digital speedometer, trip computer, coolant temperature gauge, clock, warning lights.
Traction Control:
Not typically available on these models.
Diagnostic Port:
OBD-II or proprietary Ducati diagnostic connector for ECU reading (requires specialized tools).
Oil Change Interval:
Typically every 7,500 km or 12 months. Check manual for specific Ducatidrive recommendations.
Desmo Service Interval:
Valve clearance (Desmodromic service) typically every 10,000-12,000 km. This is a critical and specialized service for Ducati engines.
Belt Replacement Interval:
Timing belt replacement every 2-3 years or 20,000 km, whichever comes first. Crucial to prevent catastrophic engine damage.
Engine Oil:
Synthetic 10W-40 or 20W-50, meeting API SG/SH/SJ or higher. Ducati often recommended specific brands or viscosity grades.
Coolant:
Ethylene glycol-based antifreeze with corrosion inhibitors, typically a 50/50 mix with distilled water.
Brake Fluid:
DOT 4 or DOT 5.1 (check manual for precise specification), changed every 2 years.
Clutch Fluid:
DOT 4, same as brake fluid.
Gearbox Oil:
SAE 75W-90 or 80W-90 gear oil (API GL-4 or GL-5).
Desmo Service:
Proper adjustment of desmodromic valve clearances is critical; neglect can lead to valve damage. Requires specialized knowledge.
Timing Belts:
Belts degrade over time; failure is catastrophic. Regular replacement is non-negotiable.
Electrical Connections:
Some older Ducatis experienced issues with corroded electrical connectors, particularly in humid environments.
Fuel Pump:
In-tank fuel pumps can be a point of failure; proper diagnosis is key.
Regulator Rectifier:
While less common than on earlier models, checking charging system output is always prudent.
Ducati Legacy:
Ducati's reputation for performance V-twins, racing pedigree, and distinctive Italian design.
St Series Origin:
The ST series evolved from Ducati's desire to create a more versatile sportbike capable of comfortable long-distance touring without sacrificing performance.
St4 Vs St4S:
The ST4 utilized the 916 engine, while the ST4s (introduced later) incorporated the more powerful 996 engine, along with upgraded suspension (Öhlins) and wheels (Marchesini) for improved performance and handling.
Manufacturing Location:
Bologna, Italy
