Market Segment:
High-performance British parallel-twin motorcycle.
Key Competitors:
BSA Gold Star, Norton Dominator, Royal Enfield Interceptor.
Performance Focus:
Renowned for power, speed, and distinctive 'rumble' exhaust note.
Brand Reputation:
Triumph's legacy in performance motorcycling, particularly with the 650cc unit construction engine.
Owner Benefit:
Essential guide for new owners to understand and maintain their classic Triumph motorcycle correctly, ensuring longevity and optimal performance.
Engine Systems:
Engine identification, lubrication, cooling, starting, ignition, carburetion ( Amal Monobloc, possibly Type 620 for T120R), exhaust.
Transmission Drivetrain:
Gearbox operation, clutch, chain drive, lubrication.
Chassis Suspension:
Front forks (Telescopic), rear suspension (swingarm with twin shock absorbers), wheels, spokes, tires.
Brakes:
Front brake (Drum, possibly Girling), rear brake (Drum, possibly Triumph Duplex), operation and adjustment.
Electrical System:
Lighting system (Lucas electrics), battery care, wiring diagrams (typically not detailed in owner's manual but may have basic functional descriptions), ignition timing (basic checks).
Controls Instruments:
Handlebar controls, instrument panel (speedometer, tachometer, ammeter), fuel gauge (if applicable).
Routine Maintenance:
Pre-ride checks, oil level checks, chain lubrication and adjustment, brake adjustment, tire pressure checks, cleaning and polishing.
Basic Troubleshooting:
Starting difficulties, ignition issues (basic checks), fuel delivery problems (basic checks).
Storage Seasonal Care:
Recommendations for short-term and long-term storage, winterization.
Depth Level:
Basic operational guidance and routine owner maintenance. Does not typically include detailed disassembly, repair procedures, or comprehensive wiring schematics found in factory service manuals.
Engine Type:
Air-cooled, parallel-twin (vertical twin).
Displacement:
649 cc (39.6 cu. in.)
Bore X Stroke:
71 mm x 82 mm (2.79 in x 3.23 in)
Compression Ratio:
Typically 8.5:1 to 9.5:1 depending on model variant (e.g., 'R' for road, 'C' for competition/custom).
Horsepower Output:
Approximately 40-45 bhp (net) at 6,500 rpm, depending on tuning and specific model.
Torque Output:
Around 37-40 lb-ft at 4,000 rpm.
Carburetor Type:
Single Amal Monobloc (e.g., 30mm or 32mm) for TR6 models and some T120 variants; Twin Amal Monoblocs for high-performance T120R Bonneville.
Fuel Type:
Leaded gasoline (e.g., 91-98 octane RON equivalent), though hardened valve seats were often a later addition or modification for unleaded use.
Oil System:
Integrated dry-sump lubrication system with oil contained within the frame backbone and a scavenge pump.
Oil Capacity:
Approximately 4.5 Imperial pints (2.5 liters) of engine oil.
Oil Change Interval:
Typically every 1,000 - 2,000 miles (1,600 - 3,200 km) or every 3-6 months, whichever comes first.
Major Service Interval:
Every 3,000 - 5,000 miles (4,800 - 8,000 km) for valve adjustments, ignition timing checks, and carb tuning.
Engine Oil Type:
SAE 50 or SAE 20W-50 motorcycle-specific oil. Emphasis on oil suitable for wet clutches and high-temperature operation.
Gearbox Oil Type:
Gearbox oil (often shared with engine oil in early unit construction) or specific gearbox oil as per manual.
Fork Oil Type:
Triumph specifies specific fork oil, often a lightweight hydraulic oil. Capacity around 6-7 Imperial fluid ounces per leg.
Engine Wear Points:
Valve guides, piston rings, and primary chain wear are common due to age and mileage.
Electrical Gremlins:
Lucas electrics of the era can be prone to issues; proper wiring maintenance and connections are crucial.
Carburetor Tuning:
Amal carburetors require regular cleaning and adjustment for optimal performance. Jetting may need to be specific to altitude and fuel.
Oil Leaks:
Common on vintage British motorcycles; gasket and seal integrity needs monitoring.
Oil Filter Type:
Early models often feature an oil strainer or filter screen within the crankcase rather than a spin-on or cartridge filter.
Triumph Legacy:
Triumph Motorcycles, a storied British brand with a long history of innovation and performance, dating back to 1902.
650 Twins Development:
The 650cc parallel twin engine was a significant development for Triumph, evolving from earlier 500cc and 600cc twins. The unit construction engine, introduced in the late 1950s, was a major step forward in design and packaging.
1965 Updates:
The 1965 models refined the previous years' designs, often featuring improved chassis components, braking systems, and engine tuning for various models like the Bonneville (high performance) and Tiger (more robust).
Manufacturing Location:
Meriden Works, Coventry, England.
Significance:
The 650cc models, especially the Bonneville, became iconic in the 1960s and were highly sought after by riders seeking speed and style.
Model Acclaim:
The Bonneville T120 variant, in particular, gained significant popularity and acclaim for its performance and styling, becoming a symbol of the 1960s motorcycle culture.
Performance Reviews:
Contemporary reviews lauded the power and handling of the 650 twins, though often noted the demanding nature of their maintenance.
Historic Significance:
Recognized as a significant milestone in motorcycle engineering and a highly collectible vintage motorcycle.
