Engine:
Complete engine disassembly, assembly, tuning, and repair for the 123cc two-stroke engine.
Transmission:
Clutch, gearbox, shift mechanism, lubrication, and maintenance.
Fuel System:
Carburetor (Mikuni VM series), fuel tank, fuel lines, and associated components.
Ignition System:
CDI (Capacitor Discharge Ignition) system, stator, coil, spark plug specifications.
Cooling System:
Air-cooled cylinder and cylinder head cooling.
Exhaust System:
Expansion chamber, muffler, and related components.
Suspension Front:
Front fork (KYB or similar), seals, oil type and level, damping adjustments.
Suspension Rear:
Monoshock rear suspension, linkage system, shock absorber, spring preload, rebound damping.
Brakes Front:
Drum brake system, brake shoes, brake cable, linkage adjustment.
Brakes Rear:
Drum brake system, brake shoes, brake cable, linkage adjustment.
Wheels And Tires:
Wheel bearings, spoke tension, tire types and pressures, rim specifications.
Electrical System:
Basic lighting (if equipped), kill switch, wiring harness.
Frame And Bodywork:
Chassis inspection, fasteners, fenders, seat, handlebars, graphics.
Routine Maintenance:
Oil changes, filter cleaning/replacement, spark plug inspection, chain lubrication and adjustment, air filter service.
Engine Repair:
Top-end rebuild (piston, rings, cylinder), bottom-end rebuild (crankshaft, bearings), valve adjustments (not applicable for 2-stroke), gasket replacement.
Transmission Repair:
Clutch plate replacement, gear inspection, shift drum and fork alignment.
Carburetor Service:
Disassembly, cleaning, jetting recommendations, float height adjustment, idle speed adjustment.
Suspension Overhaul:
Fork seal replacement, fork oil change and level adjustment, rear shock service and adjustment.
Brake Service:
Brake shoe replacement, brake cable adjustment, drum cleaning.
Troubleshooting:
Diagnosing common problems such as starting issues, poor running, and power loss.
Wiring Diagrams:
Schematics for electrical components, ignition system, and lighting (if applicable).
Depth:
Comprehensive, covering everything from basic maintenance to complete engine and chassis rebuilds. Suitable for both amateur and professional mechanics.
Type:
123cc Liquid-Cooled, Reed Valve, Two-Stroke Single Cylinder
Bore X Stroke:
56mm x 50mm (approximate, requires confirmation from manual)
Compression Ratio:
Requires manual verification, typically around 7.5:1 to 8.5:1 for this era.
Carburetor:
Mikuni VM Series (specific model number like VM28SS or similar to be confirmed).
Horsepower:
Approximately 25-30 HP (estimate, actual output depends on condition and tuning).
Torque:
Requires manual verification.
Fuel Type:
Unleaded gasoline with proper two-stroke oil pre-mix.
Premix Ratio:
Typically 20:1 or 32:1, consult manual for exact specification.
Type:
Premix lubrication for engine internals.
Oil Change Engine:
N/A (2-stroke premix)
Air Filter Cleaning:
Every few riding hours or as dictated by conditions (refer to manual).
Chain Lubrication:
Every ride or as needed, depending on conditions.
Spark Plug Inspection:
Periodically, as per manual recommendations.
Fork Oil Type:
Specific viscosity and weight to be confirmed in manual (e.g., SAE 10W).
Transmission Oil Type:
Requires manual verification for type and capacity (typically a specific gear oil).
Coolant Type:
N/A (Air-cooled)
Common Wear Items:
Piston rings, clutch plates, suspension seals, carburetor jets, chain and sprockets.
Maintenance Importance:
Proper engine tuning and regular maintenance are crucial for optimal performance and longevity of this 2-stroke engine.
