Production Years Covered:
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
Vehicle Type:
Off-Road Motorcycle (Motocross/Enduro)
Segment:
High-performance off-road competition motorcycles
Target Audience:
Motocross and Enduro enthusiasts, racers, mechanics, and DIY owners
Competitors:
Yamaha YZ125, Honda CR125R, Suzuki RM125, Kawasaki KX125 (during the covered years)
Performance Focus:
Lightweight chassis and powerful 125cc two-stroke engine optimized for racing
Manual Benefit:
Enables owners to maintain and repair their high-performance machinery effectively, maximizing performance and longevity
Engine:
Complete engine disassembly, assembly, tuning, and troubleshooting
Transmission:
Gearbox inspection, repair, and maintenance
Chassis:
Frame, subframe, swingarm, and linkage maintenance
Suspension:
Front fork (WP USD) and rear shock absorber servicing, adjustments, and rebuilds
Fuel System:
Carburetor (likely Keihin PWK) tuning, cleaning, and rebuilding; fuel tank and petcock maintenance
Cooling System:
Radiator, hoses, and coolant maintenance
Electrical System:
Ignition system, lighting (if applicable), wiring diagrams, battery, and stator maintenance
Braking System:
Front and rear brake caliper, master cylinder, hose, and fluid service
Clutch System:
Hydraulic clutch operation, maintenance, and bleeding
Exhaust System:
Exhaust pipe and silencer maintenance
Wheels And Tires:
Wheel bearing maintenance, spoke tensioning, tire changes
Maintenance:
Scheduled maintenance, lubrication, filter changes, spark plug replacement
Troubleshooting:
Diagnostic guides for common and uncommon issues
Disassembly:
Step-by-step guides for removing and separating all major components
Assembly:
Detailed instructions for reassembling components and the entire vehicle
Repair:
Instructions for fixing worn, damaged, or malfunctioning parts
Adjustment:
Carburetor jetting, suspension sag, chain tension, clutch play, etc.
Installation:
Guidance on installing new or replacement parts
Torque Specifications:
Detailed torque values for all critical fasteners
Depth:
In-depth, professional-level repair and overhaul procedures
Illustrations:
Extensive use of pictorial diagrams, exploded views, and photographs
Special Tools:
Identification and usage instructions for specialized service tools
Wear Limits:
Specific measurements for checking component wear and determining replacement necessity
Type:
Liquid-cooled, 2-stroke single-cylinder
Displacement:
Approximately 125cc (specific exact displacement for SXS variant may vary slightly but is based on the 125 SX platform)
Bore X Stroke:
Typically around 54mm x 54.5mm for 125cc KTM two-strokes of this era
Horsepower Est:
Estimated 35-40+ HP depending on year and specific SXS tuning
Torque Est:
Estimated 20-25 Nm
Carburetor Model:
Likely Keihin PWK (e.g., 38mm)
Fuel Type:
Unleaded gasoline with appropriate 2-stroke oil pre-mix
Type:
Digital CDI (Capacitive Discharge Ignition)
Oil Change Interval:
Gearbox oil change typically every 10-15 hours of riding or annually
Piston Ring Replacement:
Recommended every 30-50 hours of racing/hard use
Top End Rebuild:
Recommended every 50-80 hours of racing/hard use (piston, rings, small end bearing)
Clutch Inspection:
Regular inspection of clutch plates for wear
Gearbox Oil:
KTM recommends specific transmission oils (e.g., Motorex Gear Oil 10W/40 or equivalent JASO MA certified oil)
Coolant:
Ethylene glycol based coolant with corrosion inhibitors (typically 50/50 mix with distilled water)
Brake Fluid:
DOT 4 brake fluid
Common Wear Items:
Piston, piston rings, clutch plates, wheel bearings, fork seals, chain and sprockets
Carburetor Tuning:
Sensitivity to altitude, temperature, and humidity changes requiring regular jetting adjustments
Suspension Maintenance:
Requires regular fork oil changes and seal replacements for optimal performance