Segment:
Classic British Motorcycle, Modern Classic Segment
Target Audience:
Enthusiasts, owners seeking to maintain or restore their Bonneville.
Competitors:
Other parallel-twin motorcycles of the era, custom builds.
Design Philosophy:
Retro styling with modern engineering for reliability and performance.
Appeal:
Timeless aesthetics, accessible performance, rich brand heritage.
Electrical System:
Comprehensive Wiring Diagrams and Troubleshooting
Chassis And Suspension:
Full Repair and Adjustment Procedures
Bodywork And Cosmetics:
Repair, Refurbishment, and Restoration Guidance
Type:
Full Service & Repair Manual
Format:
Digital (likely PDF)
Engine:
Top End, Bottom End, Cooling, Lubrication, Fuel Injection/Carburetion
Transmission:
Clutch, Gearbox, Final Drive (Chain)
Brakes:
Front and Rear Calipers, Master Cylinders, Lines, Pads, Rotors
Electrical:
Ignition, Lighting, Charging System, Instrumentation, ECU Diagnostics
Chassis:
Frame, Forks, Swingarm, Steering Head Bearings
Wheels And Tires:
Spokes, Rims, Bearings, Tire Pressures, Mounting
Routine Maintenance:
Oil Changes, Filter Replacements, Chain Adjustment, Spark Plug Replacement
Troubleshooting:
Diagnostic Flowcharts, Fault Code Interpretation, Symptom Analysis
Major Repairs:
Engine Overhaul, Transmission Rebuild, Suspension Overhaul
Adjustments:
Carburetor/Throttle Body Sync, Valve Clearances, Clutch Lever Free Play
Wiring Diagrams:
Full Color, Component Identification, Circuit Tracing
Depth:
Comprehensive: From basic owner checks to full engine and transmission rebuilds.
Diagnostic Capabilities:
Advanced, including ECU error code reading and interpretation (where applicable).
Rebuild Instructions:
Detailed step-by-step instructions with torque specifications for all critical fasteners.
Engine Type:
Air-cooled, DOHC, parallel-twin
Displacement:
790 cc (later models often 865cc, but 2003 typically 790cc)
Bore X Stroke:
79 mm x 79 mm (for 790cc)
Compression Ratio:
9.2:1 (typical for 790cc)
Horsepower:
Approx. 61 hp @ 7400 rpm (for 790cc)
Torque:
Approx. 60 lb-ft @ 3500 rpm (for 790cc)
Fuel Delivery:
Carbureted (Keihin CVK 36mm) or early Fuel Injection depending on specific market/variant
Fuel Type:
Unleaded gasoline, 91-98 RON (Octane rating)
Oil Type:
SAE 10W-40 Synthetic or Semi-Synthetic Motorcycle Oil (API SG or higher, JASO MA certified)
Oil Capacity:
3.4 Liters (3.6 US Quarts) with filter change
Type:
5-speed constant mesh
Gear Ratios:
Specific ratios detailed in manual (e.g., 1st: 2.43, 2nd: 1.71, 3rd: 1.32, 4th: 1.09, 5th: 0.92)
Clutch Type:
Wet, multi-plate, cable-actuated
Final Drive:
Chain drive, 525 pitch (typically 104 links)
Transmission Oil Type:
SAE 80W-90 Gear Oil (API GL-4 or GL-5)
Transmission Oil Capacity:
N/A (Lubricated by engine oil)
Length:
Approx. 2230 mm (87.8 in)
Width:
Approx. 750 mm (29.5 in) at handlebars
Height:
Approx. 1100 mm (43.3 in) at seat
Wheelbase:
Approx. 1500 mm (59.1 in)
Dry Weight:
Approx. 205 kg (452 lbs)
Wet Weight:
Approx. 220 kg (485 lbs) with fluids
Gross Vehicle Weight Rating:
Approx. 400 kg (880 lbs)
Safety Certifications:
Meets relevant motorcycle safety standards of the era.
Braking System:
Hydraulic disc brakes front and rear.
Front Brake Spec:
310mm disc, 2-piston caliper
Rear Brake Spec:
282mm disc, 2-piston caliper
ABS:
Optional on some variants, not standard on all 2003 models.
Lighting:
Halogen headlight, LED taillight, turn signals.
Instrumentation:
Analog speedometer, tachometer, fuel gauge, warning lights.
Oil Change Interval:
Every 6,000 miles or 12 months, whichever comes first.
Filter Change Interval:
With every oil change.
Valve Clearance Check:
Every 12,000 miles or 24 months.
Chain Adjustment Interval:
Every 3,000 miles or as needed based on slack.
Engine Oil Spec:
SAE 10W-40 Synthetic/Semi-Synthetic Motorcycle Oil (API SG+, JASO MA)
Brake Fluid Spec:
DOT 4 (for hydraulic clutch and brake systems)
Coolant Spec:
N/A (Air-cooled engine)
Common Wear Items:
Clutch friction plates, steering head bearings, brake pads, chain and sprockets.
Potential Electrical Quirks:
Occasional issues with regulator/rectifier or stator on early models (covered in manual troubleshooting).
Carburetor Tuning:
Can require periodic synchronization and adjustment for optimal running.
Oil Filter Part Number:
e.g., Triumph OE filter 1260003-T0301, or equivalent aftermarket (e.g., Hiflofiltro HF198)
Air Filter Part Number:
e.g., Triumph OE filter T2204250, or equivalent aftermarket
Spark Plug Type:
e.g., NGK CR9EB or equivalent
Heritage:
Triumph Motorcycles Ltd. is one of the world's longest-established motorcycle manufacturers, known for iconic models.
Ancestry:
The modern Bonneville line is a revival and evolution of the legendary post-war Triumph Bonneville. The 2003 model marks the reintroduction of the Bonneville nameplate with modern engineering after Triumph's resurgence.
Key Changes 2003:
Introduction of the parallel-twin engine architecture, 5-speed gearbox, and modern chassis components, distinguishing it from older pre-unit construction models.
Manufacturing Location:
Hinckley, Leicestershire, England
Production Years:
Modern Bonneville line began in 2001. The 2003 model is part of the first generation of these modern Classics.
Model Recognition:
The Triumph Bonneville is consistently praised for its iconic styling and rideability, making it a sought-after modern classic.
Owner Satisfaction:
Generally high owner satisfaction due to its classic appeal and dependable performance when properly maintained.
Certification:
Meets all applicable European and US motorcycle safety and emissions standards for its model year.
