Scooter Segment:
Compact, urban-focused automatic scooter with a step-through design.
Target Audience:
Commuters, city riders, and recreational users seeking an economical and maneuverable personal transport.
Key Competitors:
Honda PCX125, Kymco Agility 125, SYM Fiddle II 125, Aprilia Scarabeo 100.
Engine Type:
Fuel-injected, 4-stroke, SOHC, 2-valve, air-cooled, single-cylinder.
Transmission Type:
Automatic, Continuously Variable Transmission (CVT).
Design Philosophy:
Practical, rugged styling with ample under-seat storage and a comfortable riding position.
Fuel Efficiency:
Excellent fuel economy, suitable for daily commuting.
Engine System:
Engine disassembly, assembly, inspection, troubleshooting, and repair of the 125cc fuel-injected engine.
Fuel System:
Fuel injection system (FI), fuel pump, injectors, throttle body, fuel tank, and fuel lines.
Cooling System:
Radiator, cooling fan, coolant passages, and thermostat operation.
Exhaust System:
Exhaust pipe, muffler, and catalytic converter inspection and replacement.
Transmission System:
Automatic transmission (CVT), drive clutch, driven clutch, V-belt, and final drive inspection and service.
Chassis System:
Frame, front suspension (forks), rear suspension (shock absorber), steering system, and wheel bearing service.
Braking System:
Front and rear brake systems (disc brakes), brake pads, calipers, master cylinders, brake lines, and bleeding procedures.
Electrical System:
Battery, charging system (stator, regulator/rectifier), ignition system, lighting, starter motor, and wiring diagrams.
Electronic Control Unit:
ECU diagnostics, sensor inputs (e.g., TPS, MAP, O2), and diagnostic trouble codes (DTCs).
Bodywork And Trim:
Panel removal, installation, and replacement of body panels and trim components.
Routine Maintenance:
Oil changes, filter replacements (oil, air), spark plug replacement, brake adjustments, chain lubrication (if applicable), and fluid checks.
Troubleshooting:
Systematic diagnostic procedures for common and uncommon issues, guided by symptoms and fault codes.
Engine Repair:
Complete engine rebuild procedures, including cylinder head, piston, crankshaft, and valve train servicing.
Transmission Repair:
CVT system overhaul, clutch component replacement, and final drive servicing.
Electrical Diagnosis And Repair:
Wiring harness troubleshooting, component testing (e.g., igniter, sensors), and battery system diagnostics.
Suspension And Steering Service:
Fork seal replacement, shock absorber servicing, steering bearing inspection and replacement.
Brake System Overhaul:
Brake caliper rebuilding, master cylinder replacement, and brake fluid bleeding.
Fuel Injection System Diagnosis:
Testing of fuel pump pressure, injector pulse width, and sensor readings via diagnostic tools.
Depth Level:
Comprehensive, covering basic owner maintenance to complete mechanical and electrical system overhauls.
Diagnostic Capabilities:
Detailed diagnostic trouble codes (DTCs) and step-by-step troubleshooting guides for electrical and engine issues.
Repair Complexity:
Suitable for DIY mechanics and professional technicians, offering detailed exploded views and torque specifications.
Engine Type:
4-stroke, SOHC, 2-valve, air-cooled, single-cylinder
Displacement:
125cc (124 cm³)
Bore X Stroke:
52.0 mm x 58.0 mm (typical for this engine family)
Compression Ratio:
9.2:1 (typical)
Valve Train:
SOHC (Single Overhead Camshaft), 2 valves
Horsepower Rating:
Approx. 9.6 HP @ 7,500 RPM (typical for this engine)
Torque Rating:
Approx. 9.1 Nm @ 6,000 RPM (typical for this engine)
Fuel Delivery:
Electronic Fuel Injection (FI)
Fuel Type:
Unleaded gasoline (min. 87 octane)
Fuel Tank Capacity:
Approx. 6.0 Liters (1.59 US gal)
Oil Type:
Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher, JASO MA
Oil Capacity With Filter:
Approx. 0.90 Liters (0.95 US qt)
Oil Capacity Without Filter:
Approx. 0.80 Liters (0.85 US qt)
Engine Oil Change:
Every 3,000 km (1,800 miles) or 6 months, whichever comes first.
Oil Filter Replacement:
Replace at every oil change.
Air Filter Cleaning Replacement:
Inspect every 6,000 km (3,600 miles), clean/replace as needed. Replace at 12,000 km (7,200 miles) or 24 months.
Spark Plug Replacement:
Replace at 10,000 km (6,000 miles) or 12 months.
V-Belt Inspection Replacement:
Inspect at 10,000 km (6,000 miles). Replace at 20,000 km (12,000 miles) or 24 months.
Brake Fluid Replacement:
Replace every 2 years or as needed.
Engine Oil Viscosity:
SAE 10W-40
Engine Oil Standard:
API SG or higher, JASO MA
Cooling System Coolant:
Yamaha's coolant or equivalent (50% ethylene glycol based mixture with distilled water)
Common Wear Items:
V-belt, drive/driven clutch components, front fork seals, and tires due to typical urban usage.
Fuel System Potential Concerns:
Infrequent issues with fuel pump or injector cleanliness may require cleaning or replacement if performance degrades.
Yamaha Legacy:
Yamaha Motor Company, founded in 1955, has a long history of producing high-quality motorcycles, scooters, and recreational vehicles.
Zuma Lineage:
The Zuma 125 (YW125) introduced a larger displacement and fuel injection to the popular Zuma line, which previously featured a 50cc model.
Yw125 Updates:
The 2009-2013 models represent the first generation of the fuel-injected Zuma 125, establishing its reputation for robust performance and practicality.
Manufacturing Location:
Primarily manufactured in Taiwan, with Yamaha's global quality control standards.
