Book excerpt: Each Haynes manual provides specific and detailed instructions for performing everything from basic maintenance and troubleshooting to a complete overhaul of the machine, in this case the Aprilia SR50, Rally, Sonic, Habana & Mojito Scooters, model years 1993 through 2009. Do-it-yourselfers will find this service and repair manual more comprehensive than the factory manual, making it an indispensable part of their tool box. A typical Haynes manual covers: general information; troubleshooting; lubrication and routine maintenance; engine top end; engine lower end; primary drive, clutch and external shift mechanism; transmission and internal shift mechanism; engine management system; electrical system; wheels, tires and drivebelt; front suspension and steering; rear suspension; brakes; body, and color wiring diagrams. An index makes the manual easy to navigate.