Classic and Classy Motorcycles Ltd

Historical Context
The 1978 Triumph Bonneville T140R represents a significant chapter in the storied history of Triumph motorcycles. As the quintessence of British motorcycling heritage, the T140R Bonneville, with its robust 750cc engine and 5-speed gearbox, was designed to deliver an unrivaled blend of performance and reliability. This model year continued the Bonneville's legacy of excellence, adapting to the changing tastes of riders and the increasing competition from overseas manufacturers.

Technical Specifications and Performance

• Year: 1978

• Make: Triumph

• Model: Bonneville T140R

• Engine displacement: 750cc

• Engine type: Air-cooled, four-stroke, parallel-twin

• Compression ratio: 8.6:1

• Carburetion: Twin Amal carburetors

• Ignition system: Electronic ignition upgrade available

• Cooling system: Air-cooled

• Fuel capacity: 3.8 US gallons

• Wheelbase: 58 inches

• Horsepower: 49 bhp @ 6200 rpm

• Torque: 44 lb-ft @ 3700 rpm

• Transmission type: 5-speed manual

• Frame type: Steel tubular double cradle

• Suspension system: Telescopic fork (front), Twin shock absorbers (rear)

• Braking system: Disc brake (front), Drum brake (rear)

• Dry Weight: Approximately 430 lbs

• Top speed: Approximately 110 mph

• Acceleration: 0-60 mph in about 6.5 seconds

Technical advancements
The T140R Bonneville of 1978 benefited from several technical enhancements that kept it competitive. Notably, the model featured improved carburetion and a refined 5-speed gearbox, enhancing both its performance and riding experience. Additionally, the adoption of electronic ignition (as a common upgrade) further increased reliability and ease of maintenance.

Evolution of the Model
Triumph's Bonneville series, with the T140R as a standout example, exemplifies the continuous evolution of the marque's engineering and design philosophy. This model retained the classic aesthetics beloved by Triumph enthusiasts while incorporating updates that addressed riders' needs for power, reliability, and comfort.

Cultural Impact
The 1978 Triumph Bonneville T140R, particularly when accompanied by a box of parts for restoration, symbolizes more than just a motorcycle; it represents the enduring passion for classic bikes and the joy of bringing a piece of motorcycle history back to life. The project resonates with enthusiasts dedicated to preserving the legacy of Triumph motorcycles.

Racing Heritage
While the T140R was primarily designed for the street, the Bonneville line's racing heritage, characterized by agility and power, made these models favored choices for modification by racers and custom builders. The T140R's solid foundation allows for enhancements that can unlock its potential on both the road and the track.

Competitors
In its day, the 1978 Triumph Bonneville T140R faced stiff competition from the rapidly advancing Japanese manufacturers, who offered bikes with higher performance at competitive prices. Despite this, the T140R maintained its appeal through its unmistakable British charm, distinctive style, and loyal following among motorcycle purists.