Engine System:
Full engine disassembly, assembly, tuning, and repair, including top-end (cylinder, piston, head), bottom-end (crankshaft, connecting rod, bearings), cooling system, lubrication.
Fuel System:
Carburetor tuning (Mikuni VM series likely), fuel pump, fuel lines, fuel tank maintenance.
Ignition System:
CDI ignition, spark plugs, wiring, timing adjustments.
Transmission System:
Gearbox overhaul, clutch replacement (wet multi-plate), gear shift mechanism, chain drive maintenance.
Chassis And Suspension:
Front fork (upside-down or conventional depending on sub-model), rear monoshock suspension, swingarm, linkage maintenance, bearing checks.
Braking System:
Front and rear brake caliper service, master cylinders, brake lines, disc replacement, fluid bleeding, pad maintenance.
Electrical System:
Wiring diagrams, battery maintenance, lighting (headlight, taillight, indicators), horn, starter motor, charging system (alternator/stator, regulator/rectifier).
Bodywork And Trim:
Fairing removal and installation, seat, fuel tank, fenders, mirrors, decals.
Cooling System:
Radiator service, coolant replacement, fan operation, thermostat.
Exhaust System:
Exhaust pipe and silencer inspection, repair, and removal procedures; power valve system maintenance.
Routine Maintenance:
Oil changes, filter replacements, chain adjustment and lubrication, spark plug checks, air filter cleaning/replacement, brake fluid checks, tire pressure checks.
Troubleshooting:
Diagnostic procedures for common starting, running, electrical, and braking issues.
Engine Overhaul:
Step-by-step instructions for complete engine disassembly, component inspection, repair, and reassembly.
Suspension Service:
Front fork seal replacement, oil changes, rear shock absorber inspection and adjustment.
Brake System Overhaul:
Caliper rebuilding, master cylinder replacement, bleeding procedures.
Electrical Diagnosis:
Fault finding using wiring diagrams, multimeter usage for testing components.
Carburetor Rebuild:
Jetting, float level adjustment, and cleaning procedures for Mikuni carburetors.
Wiring Diagrams:
Detailed electrical system wiring diagrams included for troubleshooting and repair.
Engine Rebuild Kits:
Information to guide the selection and installation of engine rebuild components such as piston kits, rings, and gaskets.
Depth Level:
Comprehensive; covers everything from basic fluid changes to full engine and gearbox rebuilds, with detailed torque specifications and diagnostic procedures.
Torque Specifications:
Includes precise torque values for all critical fasteners, engine components, and chassis elements.
Engine Type:
Liquid-cooled, 2-stroke, single-cylinder with power valve (Rotax 127 engine or derivatives commonly used).
Displacement:
124.4 cc (approximately)
Bore X Stroke:
Typically 54 mm x 54.5 mm (check specific sub-model variations).
Cylinder Design:
Single cylinder, two-stroke, reed valve induction with power valve control.
Horsepower Output:
Approximately 30-34 HP at 11,000-11,500 RPM (depending on market restrictions and specific model year).
Torque Output:
Approximately 19-20 Nm at 10,500 RPM.
Carburetor Model:
Mikuni VM34 or similar 34mm constant-velocity carburetor.
Fuel Type:
Unleaded gasoline, 95-98 RON (Research Octane Number).
2T Oil Type:
High-quality fully synthetic 2-stroke oil with JASO FD or better rating.
Oil Change Interval:
Every 3,000-5,000 km or annually; check gearbox oil.
Spark Plug Check:
Every 5,000 km or annually.
Chain Maintenance:
Lubricate and adjust chain every 1,000 km or as needed.
Brake Fluid Change:
Every 2 years.
Coolant Flush Interval:
Every 2 years or 30,000 km.
Engine Oil Capacity:
Gearbox oil: approx. 0.8 - 1.0 liters (check manual for exact type).
Coolant Type:
Ethylene glycol-based antifreeze coolant, mixed 50/50 with distilled water.
Brake Fluid Type:
DOT 4 brake fluid.
Common Problems List:
Carburetor jetting sensitivity, power valve sticking (due to carbon buildup), aging electrical connectors, fork seal leaks, clutch wear.
Maintenance Tips:
Regular cleaning of the power valve is crucial for optimal performance. Ensure proper fuel-to-oil ratio in premix if applicable (though most 125cc 2-strokes of this era had oil injection).
