Segment:
Premium 125cc Scooter segment.
Target Demographic:
Urban commuters seeking comfort, style, and practicality.
Key Competitors:
Honda PCX125, Suzuki Burgman 125, Kymco Xciting 125 (during the covered period).
Design:
Maxi-scooter styling, comfortable seating, aerodynamic bodywork.
Storage:
Generous under-seat storage, typically accommodating a full-face helmet.
Completeness:
Full factory specification, no limitations or trial periods.
Longevity:
Lifetime usability, no expiry dates or renewal fees.
Engine Mechanical:
Engine assembly, disassembly, inspection, overhaul, valve timing, piston/cylinder inspection, crankshaft/connecting rod inspection, lubrication system, cooling system (liquid-cooled).
Fuel System:
Fuel injection system (EFI), fuel pump, injectors, throttle body, fuel tank, fuel lines, emissions control system (EVAP).
Ignition System:
CDI ignition system, spark plugs, ignition coils, timing.
Transmission Drivetrain:
Automatic transmission (CVT - Continuously Variable Transmission) disassembly and assembly, drive belt inspection and replacement, clutch operation, final drive (gearbox) oil change and inspection.
Chassis Frame:
Frame inspection, headstock bearings, steering system maintenance.
Suspension:
Front fork (telescopic) disassembly, inspection, oil change, seal replacement. Rear shock absorber inspection and replacement.
Brakes:
Front and rear brake systems (likely hydraulic disc brakes), brake pad replacement, caliper service, brake fluid bleeding and replacement, master cylinder inspection, brake line inspection.
Electrical System:
Wiring diagrams, battery maintenance, charging system (stator, rectifier/regulator), starter motor, lighting system (headlight, taillight, indicators), horn, fuses, relays, ECU (Engine Control Unit) diagnostics.
Body Panels Trim:
Removal and installation of fairings, seat, storage compartments, and other body panels.
Routine Maintenance:
Oil changes, filter replacements (oil, air), spark plug replacement, brake fluid changes, coolant checks/changes, tire pressure checks, drive belt inspection.
Troubleshooting Diagnostics:
Step-by-step troubleshooting guides for common and uncommon issues, fault code interpretation (if applicable), diagnostic procedures for electrical and mechanical faults.
Engine Rebuild:
Complete engine disassembly, part measurement (clearances, wear limits), piston ring replacement, cylinder honing, valve lapping, gasket replacement, engine reassembly.
Transmission Repair:
CVT unit inspection, roller weight checks, clutch shoe inspection, drive and driven pulley service, gearbox disassembly and reassembly.
Electrical Diagnostics:
Testing of sensors, actuators, charging system components, starter circuit, using a multimeter and oscilloscope (implied).
Suspension Service:
Front fork seal replacement, fork oil viscosity and level checks, rear shock absorber mounting and function checks.
Brake System Overhaul:
Brake caliper piston service, master cylinder seal replacement, hydraulic system bleeding procedures.
Depth:
Comprehensive (covers all repairs, servicing, and troubleshooting).
Detail Level:
High (detailed photos & diagrams, step-by-step instructions).
Intended User:
Professional Mechanics and Technicians, Experienced DIYers.
Engine Type:
Four-stroke, SOHC, 4-valve, liquid-cooled
Displacement:
125cc class (typically around 124-125 cc)
Bore X Stroke:
Specific dimensions available in manual (e.g., 52.0 mm x 57.9 mm for some 125cc Yamaha engines).
Compression Ratio:
Typically around 11.0:1 to 12.0:1 for this class of engine.
Horsepower:
Around 10-12 HP at peak RPM (subject to regional restrictions).
Torque:
Around 9-11 Nm at peak RPM.
Fuel Delivery:
Electronic Fuel Injection (EFI) - Yamaha's 'Fuel Injection' system.
Fuel Type:
Unleaded Gasoline (RON 91 or higher).
Oil Type:
Yamalube 4 (or equivalent SAE 10W-40 API SG or higher).
Oil Capacity:
Around 0.8-1.0 Liters for oil change, with filter change (specific value in manual).
Coolant Type:
Yamaha Super Coolant (or equivalent ethylene glycol based antifreeze mixture).
Spark Plug Type:
NGK CR9E or similar (specific cross-reference available in manual).
Engine Oil Change:
Every 3,000-5,000 km or annually (refer to manual for exact interval based on usage).
Oil Filter Replacement:
Every 6,000-10,000 km or every second oil change.
Air Filter Cleaning Replacement:
Check/clean every 5,000 km, replace every 10,000-15,000 km.
Spark Plug Replacement:
Every 10,000-15,000 km.
Drive Belt Inspection Replacement:
Inspect every 10,000 km, replace every 20,000-30,000 km (depending on wear).
Brake Fluid Change:
Every 2 years or 20,000 km.
Coolant Change:
Every 2 years or 30,000 km.
Engine Oil Viscosity:
SAE 10W-40
Engine Oil API:
API SG or higher
Common Wear Items:
Drive belt, brake pads, suspension bushings, head bearings, starter motor brushes (common on many scooters).
Electrical Considerations:
Voltage regulator/rectifier failures can occur due to heat stress on older models.
Engine Performance Factors:
Loss of power can be due to clogged fuel injectors, worn drive belt, or faulty sensors.
