Target Audience:
Triumph 3TA Twenty One owners, enthusiasts, and independent repair technicians seeking detailed service and repair information.
Manual Value Proposition:
Enables owners to perform maintenance and repairs like a professional technician, saving time and money by avoiding dealership labor costs. Provides reliable information for optimal vehicle performance and longevity.
Special Tools Mention:
References special tools, often identified by Triumph part numbers and illustrations, for specific adjustments and repairs.
Proprietary Component Guidance:
Incorporates instructions for proprietary components, ensuring correct understanding and servicing of unique Triumph parts.
Market Competitors Era:
Models from manufacturers like BSA, Norton, and Royal Enfield within the lightweight motorcycle segment of the late 1950s and 1960s.
Systems Covered:
• Engine Overhaul and Repair
• Fuel System
• Ignition System
• Lubrication System
• Exhaust System
• Electrical System
• Transmission
• Chassis and Running Gear
• Brakes
• Wheels and Tires
• Bodywork and Trim
• Suspension
Engine Specifics:
Detailed procedures for engine disassembly, reassembly, piston and cylinder inspection, crankshaft and con-rod checks, valve timing, and overhaul.
Fuel System Specifics:
Carburetor adjustment, cleaning, jetting, fuel tank maintenance, and fuel line checks.
Ignition Specifics:
Spark plug replacement and gapping, ignition timing adjustment, breaker point service, coil testing, and wiring.
Electrical Specifics:
Lighting system, charging system (generator/alternator), battery maintenance, wiring diagrams, and component testing.
Transmission Specifics:
Gearbox disassembly, inspection of gears and shafts, clutch adjustment and replacement, primary drive maintenance.
Brake Specifics:
Drum brake adjustment, relining, and maintenance for both front and rear brakes.
Body Specifics:
Fender removal/installation, fuel tank mounting, seat assembly, and general trim component service.
Suspension Specifics:
Front fork maintenance (oil changes, seal replacement), rear shock absorber servicing and replacement.
Wheels Tires:
Spoke wheel tensioning, tire pressure recommendations, tube replacement procedures.
Procedures Included:
• Routine Maintenance
• Tune-ups
• Component Removal and Installation
• Assembly and Disassembly
• Troubleshooting
• Repair Procedures
• Overhaul Procedures
• Diagnostic Procedures
Tune Up Details:
Step-by-step guide for achieving optimal engine performance, including carburetor and ignition settings.
Removal Install Details:
Detailed instructions for removing and reinstalling major components like the engine, gearbox, wheels, and body panels.
Technical Depth:
Comprehensive, assuming general automobile practices. Emphasizes product-specific aspects and includes proprietary component manufacturer instructions where applicable.
Diagnostic Approach:
Provides systematic troubleshooting guides for common symptoms and faults.
Special Tool Usage:
Detailed guidance on using specialized tools for tasks like valve adjustments, bearing replacement, and engine timing.
Engine Type:
Parallel-twin, 4-stroke
Displacement:
213cc (approx.)
Bore X Stroke:
63.5 mm x 69 mm (2.50 in x 2.72 in)
Horsepower:
Approx. 16-18 bhp (varies slightly by tuning and year)
Torque:
Not explicitly stated, but characteristic of small displacement twins of the era.
Carburetion:
Single Amal carburetor (specific model varies, e.g., Amal Monobloc)
Ignition Type:
Coil and Distributor (or Magneto depending on specific build)
Lubrication System:
Wet sump
Cooling Method:
Air-cooled
Required Safety Equipment:
Safety glasses, gloves, proper footwear. Emphasis on torque wrench usage for fastener tightening.
Crash Test Ratings:
N/A (Historical vehicle, no modern crash ratings apply)
Braking System:
Drum brakes, front and rear.
Tune Up Interval:
As needed or specified in manual (typically involves spark plugs, ignition timing, carburetor adjustment).
Engine Oil Type:
Typically SAE 20W-50 or SAE 30 motorcycle specific oil (refer to manual for precise recommendations).
Transmission Oil Type:
Motorcycle specific gearbox oil (refer to manual for precise recommendations).
Fork Oil Type:
Specific fork oil viscosity recommended (refer to manual).
Brake Fluid Type:
Typically DOT 3 or DOT 4 for older drum brake systems if hydraulic (though often cable actuated).
Common Wear Items:
Ignition points, carburetor gaskets, clutch plates, electrical wiring insulation degradation over time.
Carburetor Issues:
Float bowl leaks, jet clogging, vacuum slide sticking.
Electrical Issues:
Loose connections, worn wiring insulation, weak charging from generator.
Engine Issues:
Oil leaks from gaskets, valve stem seal wear, potential primary chain wear.
Manufacturer Origin:
United Kingdom
Model Development:
The 3TA Twenty One was a popular lightweight motorcycle produced by Triumph, known for its reliability and ease of use in its era.
Key Design Elements:
Unit construction engine and gearbox, distinctive 'bathtub' rear mudguard on some variants.
Production Period:
1957-1966 (with the covered years being 1959-1966).
