Positioning:
The Husqvarna SM 125 was positioned as an entry-level to mid-range supermoto, offering nimble handling and accessible performance for both street use and light off-road excursions. It appealed to riders seeking a sporty and engaging machine.
Competitors:
Competed with other 125cc supermoto/motard offerings from brands like KTM (e.g., 125 EXC/Supermoto variants), Yamaha (e.g., WR125X), and Aprilia (e.g., SX125).
Key Features:
Lightweight chassis, torquey 125cc two-stroke engine, capable suspension, and agile handling characteristic of supermoto design.
Target Audience:
Professional technicians and DIY mechanics with basic mechanical and electrical knowledge.
Engine Mechanical:
Detailed disassembly, assembly, inspection, and repair of the 125cc two-stroke engine (e.g., piston, rings, cylinder, crankshaft, bearings, seals).
Engine Fuel System:
Carburetor adjustment, cleaning, and overhaul (likely Mikuni VM series), fuel lines, and fuel tank maintenance.
Engine Ignition System:
Spark plug selection, ignition timing, stator, CDI unit, and wiring diagrams.
Engine Exhaust System:
Exhaust pipe and silencer maintenance.
Engine Cooling System:
Liquid cooling system maintenance, coolant type, radiator, and water pump.
Transmission Gearbox:
Gearbox oil change intervals and specifications, disassembly and assembly of gearbox components.
Clutch System:
Clutch operation, adjustment, and component replacement (e.g., plates, springs).
Electrical System Wiring:
Comprehensive wiring diagrams for all electrical components, including lighting, indicators, and ignition.
Suspension Front:
Front fork service, oil levels, seals, spring replacement, and adjustment procedures.
Suspension Rear:
Rear shock absorber service, linkage maintenance, and adjustment procedures.
Brakes Front:
Brake caliper service, pad replacement, fluid bleeding, master cylinder overhaul, and disc inspection.
Brakes Rear:
Rear brake caliper service, pad replacement, fluid bleeding, master cylinder overhaul, and disc inspection.
Wheels Tires:
Tire pressure recommendations, wheel bearing maintenance, and spoke tensioning.
Frame Chassis:
Frame inspection for damage, steering head bearing service.
Bodywork Plastics:
Fairing, seat, and fender removal and installation.
Disassembly:
Complete step-by-step instructions for disassembling all major components.
Assembly:
Detailed assembly procedures with torque specifications.
Cleaning:
Specific instructions for cleaning engine parts, carburetors, and other components.
Reinstallation:
Guidance on reinstalling components correctly after service.
Troubleshooting Diagnostics:
Systematic approach to diagnosing and resolving common problems.
Preventative Maintenance:
Recommended maintenance tasks and their intervals.
Adjustments:
Instructions for adjusting clutch, throttle, brakes, and carburetor.
Depth Level:
Comprehensive: Suitable for professional technicians and experienced DIY mechanics. Covers from basic maintenance to full engine rebuilds.
Engine Type:
125cc liquid-cooled, two-stroke, single-cylinder
Bore X Stroke:
Specific dimensions not provided, but typical for 125cc two-stroke racing engines of the era.
Horsepower:
Approx. 30-35 HP (peak, depending on tuning and specific variant). Precise figures require factory data.
Torque:
Specific figures not provided, but characterized by strong low-to-mid-range torque typical of performance two-strokes.
Carburetor Model:
Likely Mikuni VM30 or similar.
Fuel Type:
Unleaded gasoline (minimum 95 RON recommended), mixed with appropriate two-stroke oil.
Ignition Type:
Electronic Ignition (CDI).
Cooling Method:
Liquid-cooled.
Oil Change Interval:
Details will be in the manual, typically every 3,000-5,000 km or annually for gearbox oil. Two-stroke oil is premixed or injected, not changed like gearbox oil.
Air Filter Cleaning:
Recommended every few hundred kilometers or as per manual, especially if used in dusty conditions.
Spark Plug Replacement:
Recommended every 5,000-10,000 km, depending on plug type and usage.
Top End Rebuild:
For a 125cc two-stroke performance engine, top-end rebuilds (piston, rings, cylinder inspection) might be recommended every 10,000-20,000 km depending on usage severity.
Coolant Type:
Ethylene glycol-based antifreeze/coolant with corrosion inhibitors. Specific type and mixture ratio in manual.
Brake Fluid Type:
DOT 4 hydraulic brake fluid is standard for this era.
Two Stroke Oil:
High-quality fully synthetic two-stroke oil recommended for best performance and engine longevity.
Common Issues:
Typical for 125cc two-strokes: potential for piston/ring wear if not maintained, carburetor jetting sensitivity to altitude and temperature, clutch wear, and suspension seal leaks if neglected. The manual will guide in diagnosing and rectifying these.
