Segment:
Lightweight scooter, popular for urban commuting
Competitors:
Honda PCX125, Yamaha NMAX 125, Kymco Agility 125, Piaggio Liberty 125
Attributes:
Fuel efficiency, maneuverability, practicality for city riding, often robust build quality
Engine:
Full engine overhaul, tuning, lubrication, cooling, fuel delivery, ignition
Transmission:
CVT (Continuously Variable Transmission) disassembly, inspection, adjustment, and repair
Brakes:
Hydraulic brake system diagnosis, pad replacement, fluid flush and bleed, caliper overhaul
Electrical:
Wiring diagrams, charging system, starting system, lighting, ignition system diagnostics
Suspension:
Front fork assembly, rear shock absorber service, bearings, and bushings
Bodywork:
Fairing removal and installation, seat, storage compartment, body panel repair
Cooling System:
Radiator, fan, coolant levels and replacement (if liquid-cooled)
Fuel System:
Carburetor/Fuel Injection system diagnosis and cleaning, fuel filter replacement, fuel lines
Exhaust System:
Muffler, exhaust pipe inspection and replacement
Steering:
Handlebar, steering stem, and bearings
Maintenance:
Routine service, oil changes, filter replacements, spark plug replacement, valve adjustments
Troubleshooting:
Diagnostic procedures for common and uncommon issues, fault finding guides
Repair:
Step-by-step instructions for component replacement and repair
Rebuild:
Complete engine and transmission rebuild procedures
Specifications:
Torque specifications, clearances, fluid capacities, electrical values
Diagnostic Charts:
Trouble-shooting charts based on symptoms
Wiring Diagrams:
Detailed electrical system schematics
Depth:
Comprehensive, covering all aspects from basic maintenance to full engine rebuilds and diagnostics
Engine Type:
Four-stroke, single-cylinder, likely air-cooled or liquid-cooled (specific details depend on exact 'HD125' variant)
Displacement:
Approximately 125cc
Bore X Stroke:
Varies by specific engine variant, typical for 125cc scooter engines
Horsepower:
Typically in the range of 8-12 HP (for 125cc scooters)
Torque:
Typically around 9-11 Nm (for 125cc scooters)
Fuel Delivery:
Likely Fuel Injection (FI) or Carburetor, depending on year and market
Fuel Type:
Unleaded Gasoline
Valve Train:
SOHC (Single Overhead Camshaft) 2-valve or 4-valve configuration common
Length:
Varies by specific model iteration, typically around 1900-2000 mm
Width:
Varies by specific model iteration, typically around 700-750 mm
Height:
Varies by specific model iteration, typically around 1100-1200 mm
Dry Weight:
Typically in the range of 110-130 kg
Curb Weight:
Typically in the range of 120-140 kg (with fluids)
Max Load Capacity:
Typically around 150-180 kg (rider + cargo)
Underseat Storage:
Standard feature, capable of holding a full-face helmet (depending on helmet size)
Crash Test Data:
N/A for scooters in most jurisdictions, focus is on design and braking effectiveness
Braking System:
Disc brakes front and rear (common), some models may have drum rear brake or linked braking systems (CBS)
Lighting:
Halogen or LED headlight, taillight, and turn signals
Frame Construction:
Steel underbone frame for rigidity and durability
Display:
Digital or analog instrument cluster with speedometer, fuel gauge, odometer, etc.
ABS:
Optional on some later models, but not standard on all 125cc scooters.
Charging Port:
Often includes a 12V power outlet or USB charging port in the glove box.
Oil Change Interval:
Typically every 3,000 - 5,000 km or annually, whichever comes first (refer to manual for exact specification)
Air Filter Replacement:
Recommended every 6,000 - 10,000 km or as needed
Spark Plug Replacement:
Typically every 5,000 - 10,000 km
Belt Inspection Replacement:
CVT belt inspection typically around 10,000 km, replacement usually around 20,000 - 30,000 km (highly dependent on usage)
Engine Oil Type:
SAE 10W-40 API SG or higher (confirm with manual for exact specification)
Engine Oil Capacity:
Approximately 0.8 - 1.0 Liters (refer to manual for exact capacity)
Brake Fluid Type:
DOT 3 or DOT 4 (confirm with manual)
Coolant Type:
Ethylene glycol-based antifreeze (if liquid-cooled)
Common Problems:
CVT belt wear, occasional electrical connector issues, general wear and tear on suspension components with high mileage.
Manufacturer:
Sanyang Motor Co., Ltd. (SYM) is a Taiwanese manufacturer known for scooters, motorcycles, and mobility products.
Development:
The HD series represents SYM's commitment to stylish, practical, and efficient urban mobility scooters.
