Market Position:
The Aprilia RS125 was a highly regarded lightweight sportbike, known for its sharp styling, agile handling, and performance that punched above its weight class. It served as an entry point into performance motorcycling for many riders, particularly in Europe.
Competitors:
Competed directly with other 125cc two-stroke sportbikes of the era, such as the Yamaha TZR125, Honda NSR125, Suzuki RG125, and Cagiva Mito 125.
Key Features:
Aggressive styling, excellent chassis dynamics, powerful two-stroke engine (for its class), sophisticated suspension and braking components.
Covered Years:
1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
Vehicle Type:
Sportbike Motorcycle
Page Count:
Estimated 300-400 pages (typical for comprehensive workshop manuals)
Manual Type:
Workshop Manual / Service Manual / Repair Manual
Language:
English (typical for global distribution)
Format:
Digital Download (PDF)
Engine:
Two-stroke engine overhaul, top end rebuild, bottom end assembly, cylinder, piston, rings, crankshaft, bearings, seals
Fuel System:
Carburetor tuning and rebuilding (e.g., Dell'Orto PHBH 28/30), fuel pump, fuel lines, fuel tank maintenance
Cooling System:
Radiator, water pump, thermostat, coolant flow, hoses, bleeding procedures
Electrical Equipment:
Ignition system (CDI, coil, spark plug), lighting, charging system (stator, regulator/rectifier), battery, starter motor, wiring diagrams, troubleshooting electrical faults
Cycle Parts:
Frame inspection, suspension (forks, rear shock absorber), steering head bearings, wheel bearings, brake system (hydraulic discs front and rear, master cylinders, calipers, pads, fluid), clutch system, chain and sprockets, exhaust system
General Information:
Vehicle identification numbers (VIN), general specifications, torque values, special tools, safety precautions
Periodic Maintenance:
Scheduled maintenance intervals, oil changes, filter replacements, chain lubrication, spark plug checks, brake fluid changes
Repair Procedures:
Step-by-step instructions for component disassembly, repair, reassembly, and adjustment
Troubleshooting:
Diagnostic charts and guides for identifying and resolving common problems
Technical Data:
Specifications, tolerances, clearances, and diagnostic data for all major components
Depth:
Comprehensive; covers from basic maintenance and fluid checks to complete engine and chassis overhauls
Engine Type:
Liquid-cooled, two-stroke, single-cylinder
Displacement:
124.8 cc (approximately)
Bore X Stroke:
54 mm x 54.5 mm (typical for Rotax 122)
Compression Ratio:
12.5:1 (typical, can vary slightly with model year)
Power Output:
Approximately 30-34 hp (22-25 kW) at 11,000 rpm (depending on homologation and restrictions for license classes)
Torque:
Approximately 18-20 Nm at 10,000 rpm
Lubrication:
Pre-mix or separate oil injection system (autolube)
Carburetor:
Dell'Orto PHBH 28/30 AS or similar
Fuel Type:
Unleaded gasoline (min. 95 octane recommended)
Cooling Medium:
Water/glycol mixture
Braking System:
Hydraulic disc brakes front and rear. Front typically a 320mm disc with a 4-piston caliper (e.g., Brembo or Grimeca), rear a 220mm disc with a 2-piston caliper.
Lighting:
Halogen headlight, LED taillight (depending on year/market), turn signals
Instrument Cluster:
Analog tachometer, speedometer, odometer, trip meter, coolant temperature warning light, oil warning light, neutral indicator.
ABS:
Anti-lock Braking System (ABS) was not a standard feature on most RS125 models of this era, though it may have been an optional fitment on some later or specific market variants.
Oil Change Interval:
Engine oil (if applicable, for gearbox): every 5,000-7,000 km or annually. Gearbox oil: every 7,500-10,000 km.
Spark Plug Replacement:
Check every 2,500-5,000 km, replace as needed. Recommended type: NGK BR9EG or equivalent.
Chain Maintenance:
Lubricate and adjust chain every 500-1,000 km. Replace chain and sprockets typically between 15,000-30,000 km, depending on maintenance and riding conditions.
Brake Fluid Flush:
Every 12-24 months. Recommended fluid: DOT 4.
Gearbox Oil:
API GL-4, SAE 75W-90 or 80W-90 transmission oil. Capacity: approx. 0.8-1.0 liters.
Coolant:
Ethylene glycol-based coolant mixed with distilled water (50/50 ratio). Total capacity: approx. 1.5 liters.
2 Stroke Oil:
High-quality synthetic 2-stroke oil (e.g., Motul 710, Castrol TTS). Use specifically for autolube system or pre-mix as per manual.
Common Issues:
Worn power valve mechanism, sticky exhaust power valve, carburetor jetting sensitivity, starter motor reliability (early models), stator failures, frequent spark plug fouling (if not jetted/maintained correctly), excessive vibration at higher RPMs.
Common Fixes:
Regular cleaning and adjustment of the power valve, proper carburetor jetting for local conditions, ensuring battery health, inspecting stator and regulator/rectifier, using correct spark plug heat range.
Brand Origin:
Aprilia is an Italian motorcycle manufacturer founded in 1945, known for its performance-oriented motorcycles, especially in the racing and sportbike segments.
Rs125 Lineage:
The RS125 built upon the legacy of Aprilia's successful 125cc racing machines and models like the AF1 and Tuareg. It was continuously refined throughout its production run, receiving updates to styling, engine performance, and chassis components.
Production Period:
1993-2003 (as covered by this manual), with earlier and later variations.
Engine Basis:
Primarily utilized the Rotax 122 engine, a robust and high-revving two-stroke unit that powered many successful racing motorcycles.
