1999 Aprilia Area 51 Scooter Service & Repair Manual (P/N 8140167)

Aprilia's service and repair manual, P/N 8140167, covers the 1999 Area 51 scooter with the Minarelli two-stroke engine. This is the first edition, November 1999, marked 960X on the cover.

Text search and wiring detail: The main text is searchable, but some headings and diagram labels are not. There are no embedded PDF bookmarks. Small labels in the general wiring diagram require magnification.

• Engine and driveline: Engine removal, support plate service, transmission oil checks and changes, and engine pivot inspection.

• Fuel and lubrication: Dell'Orto carburetor idle and throttle adjustment, fuel pump and gauge removal, and two-stroke oil tank service.

• Cooling system: Coolant draining, refilling and bleeding, radiator and expansion tank removal, and cooling-system troubleshooting.

• Brakes and steering: Front and rear disc brake service, pad replacement, hydraulic bleeding, and steering tube bearing adjustment and removal.

• Suspension: Pantograph front suspension disassembly, front and rear shock removal, and rear suspension linkage inspection.

• Electrical diagnosis: C.D.I. ignition, charging and starting circuit tests, dashboard fault tables, sensor checks, and wiring diagrams.

Written for Aprilia dealers and qualified mechanics, this manual assumes basic mechanical training and familiarity with vehicle repair procedures.

Engine Removal and Transmission Scope

The engine section covers removal from the split-cradle frame, along with the silent-block connection link and engine support plates. Transmission coverage includes oil servicing. The automatic stepless variator and centrifugal clutch are identified in the specifications, but internal engine, variator, and clutch overhaul procedures are outside this manual's scope.

The introduction refers to the separate Engine Service and Repair Manual #921, which is not included. Engine removal calls for two people and stable vehicle support.

Fuel Delivery and Two-Stroke Oil

Fuel-system diagnosis covers the vacuum tap and pump connections. The fuel level gauge removal procedure specifies special tool 8140206; separate electrical tests cover the sender and instrument.

The Dell'Orto PHBN 12 carburetor has idle and throttle-control adjustment procedures. Other procedures cover removal and cleaning of the air cleaner, plus exhaust-silencer removal.

Oil-tank service includes bleeding requirements after tank or supply-line work, with a warning that trapped air can seriously damage the engine.

Cooling System and Temperature Diagnosis

The coolant-pump and thermistor removal sections cover access and disconnection, then refer to the separate engine manual for component removal. Thermistor resistance testing and temperature-indicator checks are included here.

Chassis, Brakes and Suspension Repair

The pantograph section breaks down the horizontal and vertical arms, tie rod, pivot bearings, bushings, and seals. Rear suspension work extends to the single and double connection elements and their bearings.

Brake and wheel pages provide pad and disc wear limits, wheel inspection criteria, and tire pressure specifications. Front-wheel reassembly notes warn that forcing the wheel hub can damage the speedometer-drive teeth.

Bodywork coverage includes fairings, handlebar covers, the ignition switch/steering lock, and complete dashboard removal. Component torque tables, the Regular Service Intervals Chart, and the Lubricant Chart supply the related maintenance and reassembly data.

Electrical Fault Finding and Wiring Variants

Electrical repair coverage includes 12 wiring diagrams. Examples are the General Wiring Diagram, Ignition Circuit, Recharge and General Power Supply Circuit, and Mixer Oil Reserve and Speed Sensor Circuit, supported by component location and harness routing views.

Dashboard fault tables distinguish sensor, connector, wiring, and internal instrument faults. Separate tests for the fuel sender, coolant thermistor, and corresponding indicators help isolate a false gauge reading before replacing the dashboard.

Lighting diagrams distinguish standard, ASD automatic light switching, and Switzerland/Israel/South Korea arrangements. Starter-relay and switch continuity tests, ignition-coil checks, fuse ratings, and lighting specifications provide the related electrical reference data.

Three-Language PDF and Included Pages

English, Italian, and Spanish are combined in one printable PDF. The file has 217 pages total: 211 pages of manual text, tables, and illustrations, plus one cover and five notes pages, all included in that total.