🏷️ Basic Information

Make:

AJS

Model:

16 Series (Single), 18 Series (Twin), 31 Series (Twin)

Product Code:

AJS-Service-Manual-16-18-31

👋 Introduction

Description:

This manual caters to owners and mechanics of classic British motorcycles from AJS, specifically focusing on their popular single-cylinder and parallel-twin models from the mid-20th century. It is an essential resource for preserving and maintaining these iconic machines.

Comparison:

AJS models competed with marques like Norton, Triumph, BSA, and Matchless. This manual provides specialized information for AJS, differentiating it from broader British motorcycle service guides.

Features:

Detailed diagrams, step-by-step repair instructions, troubleshooting guides, electrical schematics, and specifications for specific AJS models.

📋 Manual Details

Manual Type:

Service and Repair Manual

Language:

English

Estimated Page Count:

200-300 (estimated based on typical factory manuals for this era)

Format:

Digital (PDF)

📖 Manual Coverage

Engine:

Engine assembly, disassembly, inspection, tuning, piston, conrod, crankshaft, cylinder head, valve gear, lubrication system, cooling system (air-cooled)

Fuel System:

Carburetor (e.g., Amal) overhaul and tuning, fuel tank, fuel lines, fuel tap

Ignition System:

Magneto ignition, coil ignition (where applicable), spark plugs, timing

Transmission:

Gearbox (e.g., Burman, AMC) overhaul, clutch operation, lubrication

Drivetrain:

Chain drive, rear hub, sprockets

Brakes:

Drum brake systems (front and rear), brake linkages, adjustments

Suspension:

Front forks (e.g., Girder, Telescopic), rear suspension (swingarm with shock absorbers), wheel bearings

Electrical System:

Lighting circuits, wiring diagrams, battery maintenance, dynamo/alternator (where applicable)

Frame And Bodywork:

Frame inspection, mudguards, fuel tank, seat, handlebars, control cables

Maintenance:

Routine checks, lubrication points and schedules, filter cleaning/replacement, spark plug maintenance, chain adjustment, brake adjustment

Troubleshooting:

Diagnosing common starting issues, engine performance problems, electrical faults, transmission noise

Repair:

Engine rebuilds, gearbox repairs, carburetor rebuilding, fork seal replacement, brake shoe replacement, electrical component repair

Overhaul:

Complete disassembly and reassembly instructions for major components

Adjustment:

Valve clearances, ignition timing, clutch cable, throttle cable, brake linkages

Depth:

Comprehensive, covering routine maintenance to complete engine and transmission rebuilds, including detailed diagrams and specifications.

📊 Manual Specifications

File Format:

PDF

Print Quality:

High-resolution scans, optimized for clarity of text and diagrams.

Binding Type:

N/A (Digital Format)

Paper Type:

N/A (Digital Format)

⚙️ Engine Specifications

Engine Types Covered:

AJS 16 Series (Single-cylinder, typically 350cc, e.g., Model 16), AJS 18 Series (Parallel-twin, typically 500cc, e.g., Model 18), AJS 31 Series (Parallel-twin, typically 600cc, e.g., Model 31 CSR).

Typical Horsepower:

Varies by model and engine size: ~18-22 bhp for 350cc singles, ~28-35 bhp for 500cc twins, ~35-40 bhp for 600cc twins (figures are approximate and depend on tune and year).

Typical Torque:

Not typically specified in peak figures for this era, but emphasis is on torque delivery for riding character.

Carburetor Examples:

Amal Concentric, Amal Monobloc (various sizes depending on model and engine variant).

Fuel Type:

Leaded gasoline (historical), unleaded gasoline with appropriate octane rating and additives recommended for vintage engines.

Oil Type Recommendation:

Typically SAE 20W-50 or SAE 30 mineral oil, or dedicated classic motorcycle oil with ZDDP additive for older engines. Refer to manual for specific grades.

Cylinder Configuration:

Single-cylinder (vertical) and Parallel-twin (vertical).

Cooling Method:

Air-cooled.

🔧 Transmission

Gearbox Type:

Constant-mesh, foot-change, typically 4-speed.

Gearbox Manufacturer Examples:

Burman, AMC (Associated Motor Cycles).

Clutch Type:

Wet multi-plate, cable-operated.

Gearbox Oil Type:

SAE 90 gear oil or specialized motorcycle gearbox oil. Refer to manual for precise specifications.

📐 Dimensions

Wheelbase:

Varies by model, typically around 54-57 inches (1370-1450 mm).

Dry Weight:

Varies by model, typically around 350-450 lbs (160-205 kg).

Wet Weight:

Varies by model, typically around 380-480 lbs (172-218 kg).

🛡️ Safety Features

Crash Test Ratings:

Not applicable for this era of motorcycle; safety focus is on mechanical integrity and predictable handling.

Braking System:

Drum brakes (single-leading or leading-trailing shoe depending on model and year) for front and rear.

Lighting:

Headlamp, tail lamp, brake light (operated by rear brake lever/pedal), indicators (optional or added later).

💡 Technology Features

Features:

N/A - Basic mechanical and electrical systems typical of 1950s-1960s motorcycles.

Features:

N/A - No electronic rider aids. Focus is on mechanical controls.

Features:

N/A - Mechanical connectivity (cables, linkages).

🔧 Maintenance

Oil Change Interval:

Typically every 2,000-3,000 miles (3,000-5,000 km) or annually. Consult manual for specific mileage.

Spark Plug Replacement Interval:

Every 3,000-6,000 miles (5,000-10,000 km), depending on plug type and usage. Check for fouling at each service.

Valve Clearance Check:

Typically every 3,000-6,000 miles (5,000-10,000 km), or when engine noise changes significantly.

Engine Oil Capacity:

Varies by model: Single-cylinder typically 3-4 pints (1.5-2 liters); Twin-cylinder typically 4-5 pints (2-2.5 liters). Consult manual for precise capacity.

Gearbox Oil Capacity:

Typically 1/2 to 1 pint (0.25-0.5 liters). Consult manual for precise capacity.

Fork Oil Type:

Typically SAE 10W or SAE 20W fork oil. Consult manual for specific type and quantity per fork leg.

Common Problems:

Oil leaks (especially from primary drive and gearbox), clutch judder, wear in gearbox dogs, charging system issues (dynamos), front fork stiction/leaks, carburetor wear affecting idle quality.

Carburetor Tuning:

Proper setting of float height, jetting, and needle position is crucial for performance and reliability, often requiring iterative adjustments.

📚 Vehicle History

Manufacturer:

Associated Motor Cycles (AMC) Group, which also produced Matchless motorcycles.

Development:

The AJS singles and twins evolved from pre-war designs, incorporating advancements like improved suspension (telescopic forks replacing girder forks), better braking systems, and more reliable electrical components through the 1950s and 1960s.

Production Period:

AJS singles and twins were produced from the late 1940s through the 1960s, with various updates and designations (e.g., 'CSR' for Competition Sport Road, 'N' for New Model).

Manufacturing Location:

Plumstead, London, England.

🏆 Awards & Recognition

Historic Racing Success:

AJS motorcycles, including models derived from the 16/18/31 series, achieved success in various motorsports, including road racing and trials, contributing to their reputation for performance and durability.

Customer Satisfaction:

Highly regarded by classic motorcycle enthusiasts for their character, sound, and the tactile riding experience they provide. Maintenance requires dedication and understanding of vintage British engineering.

Vintage Status:

Recognized as collectible vintage British motorcycles, often eligible for classic motorcycle rallies and events.