Sub Models Covered:
PK50S, PK80S, PK100S, PK110S, PK125, PK125S
Chassis Codes Primary:
V5X1T (PK50S), V8X5T (PK80S, PK100S, PK110S), V8X1T (PK125, PK125S)
Target User:
Owners, mechanics, and restorers of Piaggio Vespa PK models
Value Proposition:
Essential resource for maintaining, repairing, and restoring Vespa PK scooters
Manual Type Advantage:
Specialized workshop manual provides a depth of technical detail often missing in general owner's manuals
Model Range Coverage:
Unifies repair information for a popular and diverse range of Vespa PK models
Detail Level:
Focus on practical, actionable repair and maintenance procedures
Engine:
Complete disassembly, assembly, tuning, and troubleshooting for all engine variants
Transmission:
Gearbox inspection, repair, and adjustment (4-speed manual)
Fuel System:
Carburetor (Dell'Orto SHA, PHBL) overhaul, adjustment, and specifications; fuel tank and lines
Electrical System:
Ignition system (electronic CDI), lighting, charging system (flywheel magneto), wiring diagrams, starter motor (if applicable), horn
Brakes:
Front drum brake, rear drum brake system inspection, adjustment, and component replacement
Suspension:
Front leading link suspension inspection and overhaul, rear shock absorber and spring replacement
Chassis And Bodywork:
Frame inspection, body panel removal and installation, seat, handlebars, and controls
Wheels And Tires:
Wheel bearing inspection and replacement, tire fitment and pressure recommendations
Maintenance:
Regular servicing, lubrication points, filter changes, spark plug replacement, brake adjustment
Troubleshooting:
Diagnostic guides for common starting, running, and electrical issues
Repair:
Detailed step-by-step instructions for component overhaul and replacement across all systems
Specifications:
Torque values, clearances, fluid capacities, and settings
Wiring Diagrams:
Comprehensive electrical schematics for all covered models
Depth:
Complete workshop level, suitable for professional mechanics and experienced enthusiasts
Diagnostics:
Includes detailed diagnostic procedures and fault finding charts
Rebuilds:
Covers complete engine and gearbox rebuilds
Searchability:
Likely text-searchable PDF for efficient information retrieval
Print Readability:
Designed for clear reproduction if printed
Binding Recommendation:
Spiral binding recommended for workshop use (if physical copy)
Paper Recommendation:
Durable, wipeable paper stock recommended for workshop environments (if physical copy)
Estimated Page Count:
Likely 200-300+ pages, given the range of models and depth of coverage
Engine Type:
Two-stroke, air-cooled, single-cylinder
Displacement Pk50S:
49.77 cc
Displacement Pk80S:
78.96 cc
Displacement Pk100S:
98.3 cc
Displacement Pk110S:
108.9 cc (approx.)
Displacement Pk125:
123.7 cc
Bore X Stroke Pk125:
55 mm x 52 mm (approx.)
Compression Ratio Pk125:
9.0:1 to 10.0:1 (varies)
Horsepower Pk50S:
Approx. 3.5 - 4.5 HP
Horsepower Pk125:
Approx. 5.5 - 7 HP
Top Speed Pk50S:
Approx. 60-65 km/h
Top Speed Pk125:
Approx. 80-90 km/h
Carburetor Pk50S:
Dell'Orto SHA 14/12 F or similar
Carburetor Pk125:
Dell'Orto PHBL 25 AS or similar
Fuel Type:
Unleaded gasoline with 2-stroke oil mixture (typically 2% or 20:1 ratio)
Fuel Tank Capacity:
Approx. 3.0 liters (including ~0.5 liter reserve)
Crash Test Ratings:
Not applicable to this era of scooter in standardized formats
Brakes:
Drum brakes front and rear. Manual provides adjustment and maintenance for optimal performance.
Lighting:
Headlight, taillight, brake light, turn signals (depending on market spec). Manual covers bulb replacement and circuit checks.
Frame Structure:
Steel monocoque chassis providing structural integrity.
Safety Considerations:
Manual emphasizes correct tire pressures and brake maintenance for safe operation.
Infotainment System:
Not applicable; basic instrumentation (speedometer, fuel gauge/light, indicator lights)
Driver Assistance Features:
None; basic mechanical systems
Connectivity Options:
None
Ignition Type:
Electronic CDI (Capacitor Discharge Ignition)
Oil Change Gearbox:
Every 5,000 - 10,000 km (check manual for specific interval and oil type)
Spark Plug Replacement:
Every 3,000 - 5,000 km (or as needed based on condition)
Air Filter Cleaning Replacement:
Regularly check and clean/replace as per manual, typically every 5,000 km
Brake Adjustment:
Check and adjust cables as needed, typically every 5,000 km
Full Service Recommendation:
Annual or every 5,000 km, encompassing all major checks and adjustments
Gearbox Oil Type:
SAE 80W/90 hypoid gear oil (refer to manual for exact specification)
Gearbox Oil Capacity:
Approx. 200-250 ml (check dipstick or manual)
2 Stroke Oil Type:
High-quality, readily biodegradable 2-stroke scooter oil (API TC, JASO FD recommended)
Carburetion:
Clogged jets due to old fuel or debris; incorrect jetting for altitude or modifications.
Electrical:
Corroded connectors, failing CDI unit, weak stator output, faulty lighting circuits.
Engine:
Worn piston rings, cylinder bore wear, leaking crank seals, exhaust port blockage (coking).
Fuel System:
Leaking fuel taps, deteriorating fuel lines, tank rust.
Suspension:
Worn front fork bushes leading to sloppy handling, leaking shock absorbers.
Manufacturer:
Piaggio & C. SpA, Italy
Legacy:
Piaggio is the original creator of the Vespa scooter, a global icon since 1946.
Pk Series Introduction:
The PK series, introduced in 1977, was a significant evolution of the classic Vespa design, featuring more modern styling, direct gear selection, and improved ergonomics. The 'S' designation typically indicated sportier styling or features.
Pk Variants:
The PK range evolved with various engine sizes (50cc, 80cc, 100cc, 125cc) and specifications, including automatic transmission versions (PK Automatica) and electric start variants, though this manual focuses on manual shift models.
Production Period:
The PK series was produced roughly from 1977 through the early 1990s, with the specific variants covered likely dating from the early to mid-1980s.
Model Recognition:
The Vespa PK series is recognized as a classic and collectible scooter, representing a significant design and engineering step for Piaggio.
Editorial Reviews:
Often praised for its nimble handling, distinctive styling, and robust construction, though some found the gearbox engagement less intuitive than earlier models.
Manufacturer Standards:
Manufactured to Piaggio's internal quality and safety standards of the era.
