The KTM 625 SXC and 660 SMC were flagship single-cylinder motorcycles from the Austrian manufacturer during the turn of the millennium. These machines featured large-displacement four-stroke singles mounted in KTM signature orange trellis frames with full WP suspension. The 625 SXC focused on competitive enduro performance while the 660 SMC delivered supermoto thrills with street-oriented wheels and tires. Both shared the proven LC4-derived engine architecture featuring SOHC, liquid cooling, and electronic ignition. This workshop manual provides complete service, repair and rebuild instructions including full engine overhaul procedures, chassis and suspension maintenance, electrical system diagnostics, wiring diagrams, torque specifications and exploded view illustrations. Whether performing routine valve adjustments or a complete engine rebuild, this manual contains everything owners and mechanics need to keep these powerful KTM singles running at their best.
1998-2003 KTM 625 SXC / 660 SMC Service Repair Workshop Manual PDF
VEHICLE/EQUIPMENT INTRODUCTION:
The KTM 625 SXC and 660 SMC represent the pinnacle of Austrian enduro and supermoto engineering from the late 1990s and early 2000s. Introduced during a transformative era for KTM, these large-displacement single-cylinder motorcycles combined competition-proven Rotax-derived engine architecture with advanced chassis technology. The 625 SXC was designed as a hard-charging enduro machine with long-travel suspension, while the 660 SMC transformed the same fundamental platform into an aggressive supermoto with sticky road tires and powerful brakes. Both models featured KTM signature orange-framed trellis chassis with chromoly tubing, WP upside-down front forks, and a proven wet multiplate clutch system. These motorcycles became favorites among serious off-road enthusiasts and supermoto racers alike.
SERVICE & REPAIR SCOPE:
- Complete engine disassembly and rebuild procedures
- Cylinder head valve service and camshaft inspection
- Piston, cylinder and conrod bearing replacement
- Clutch assembly overhaul and adjustment
- Carburetor Keihin PWK jetting and tuning procedures
- Fuel tap and fuel system maintenance
- Cooling system flush, water pump inspection and thermostat testing
- Transmission gear inspection, shift drum and fork replacement
- Primary drive and starter clutch service
- Frame inspection and swingarm bearing replacement
- WP suspension overhaul, oil change and linkage service
- Steering head bearing adjustment and replacement
- Brake caliper rebuild, disc inspection and master cylinder service
- Electrical system troubleshooting, CDI and ignition coil testing
- Stator, regulator-rectifier and wiring harness inspection
- Wheel bearing replacement and spoke tension adjustment
- Exhaust system inspection and replacement
- Complete torque specifications and maintenance schedules
TECHNICAL SPECIFICATIONS:
- Engine: Liquid-cooled, single-cylinder, 4-stroke, SOHC
- Displacement: 625 cc (625 SXC) / 660 cc (660 SMC)
- Bore x Stroke: approximately 100 x 80 mm
- Compression ratio: varies by model year 9.5:1 to 11.3:1
- Induction: Keihin PWK carburetor 41mm
- Transmission: 5-speed or 6-speed constant mesh
- Clutch: Wet multiplate, hydraulically actuated
- Frame: Chrome-molybdenum steel trellis frame
- Front Suspension: WP USD forks, 48mm
- Rear Suspension: WP monoshock with linkage
- Brakes: Front 300mm+ disc, Rear single disc
- Dry Weight: approximately 125-135 kg depending on model
DIAGNOSTIC INFORMATION:
- Hard starting or no start diagnostics covering compression, spark and fuel delivery
- Valve clearance symptoms and adjustment intervals
- Overheating causes and cooling system pressure testing
- Clutch slipping diagnosis and plate wear inspection
- Gear jumping out of selected ratio and shift drum inspection
- Excessive chain/sprocket wear and final drive troubleshooting
- Abnormal engine noise top-end and bottom-end diagnosis
- WP suspension bottoming and damping adjustment guidance
- Electrical faults including no spark, intermittent firing, and charging issues
- Carburetor flooding, hesitation and flat spot tuning remedies
ILLUSTRATIONS & DIAGRAMS INCLUDED:
- Exploded views of complete engine assembly with part numbers
- Wiring diagrams for all model years
- Fuel system and carburetor cross-section illustrations
- Suspension assembly and linkage diagrams
- Frame geometry and chassis component illustrations
- Brake hydraulic system schematics
- Exhaust routing and mounting details
COMPATIBILITY:
- Covers KTM 625 SXC model years 1998, 1999, 2000, 2001, 2002, 2003
- Covers KTM 660 SMC model years within same period
- Applicable to all variants within these year ranges
- Service procedures align with Rotax 640/660 LC4-based engine family
FILE PROPERTIES:
- Format: Searchable PDF
- Language: English
- Delivery: Instant digital download
- Access: Download anytime after purchase
1998-2003 KTM 625 SXC / 660 SMC Service Repair Workshop Manual PDF
VEHICLE/EQUIPMENT INTRODUCTION:
The KTM 625 SXC and 660 SMC represent the pinnacle of Austrian enduro and supermoto engineering from the late 1990s and early 2000s. Introduced during a transformative era for KTM, these large-displacement single-cylinder motorcycles combined competition-proven Rotax-derived engine architecture with advanced chassis technology. The 625 SXC was designed as a hard-charging enduro machine with long-travel suspension, while the 660 SMC transformed the same fundamental platform into an aggressive supermoto with sticky road tires and powerful brakes. Both models featured KTM signature orange-framed trellis chassis with chromoly tubing, WP upside-down front forks, and a proven wet multiplate clutch system. These motorcycles became favorites among serious off-road enthusiasts and supermoto racers alike.
SERVICE & REPAIR SCOPE:
- Complete engine disassembly and rebuild procedures
- Cylinder head valve service and camshaft inspection
- Piston, cylinder and conrod bearing replacement
- Clutch assembly overhaul and adjustment
- Carburetor Keihin PWK jetting and tuning procedures
- Fuel tap and fuel system maintenance
- Cooling system flush, water pump inspection and thermostat testing
- Transmission gear inspection, shift drum and fork replacement
- Primary drive and starter clutch service
- Frame inspection and swingarm bearing replacement
- WP suspension overhaul, oil change and linkage service
- Steering head bearing adjustment and replacement
- Brake caliper rebuild, disc inspection and master cylinder service
- Electrical system troubleshooting, CDI and ignition coil testing
- Stator, regulator-rectifier and wiring harness inspection
- Wheel bearing replacement and spoke tension adjustment
- Exhaust system inspection and replacement
- Complete torque specifications and maintenance schedules
TECHNICAL SPECIFICATIONS:
- Engine: Liquid-cooled, single-cylinder, 4-stroke, SOHC
- Displacement: 625 cc (625 SXC) / 660 cc (660 SMC)
- Bore x Stroke: approximately 100 x 80 mm
- Compression ratio: varies by model year 9.5:1 to 11.3:1
- Induction: Keihin PWK carburetor 41mm
- Transmission: 5-speed or 6-speed constant mesh
- Clutch: Wet multiplate, hydraulically actuated
- Frame: Chrome-molybdenum steel trellis frame
- Front Suspension: WP USD forks, 48mm
- Rear Suspension: WP monoshock with linkage
- Brakes: Front 300mm+ disc, Rear single disc
- Dry Weight: approximately 125-135 kg depending on model
DIAGNOSTIC INFORMATION:
- Hard starting or no start diagnostics covering compression, spark and fuel delivery
- Valve clearance symptoms and adjustment intervals
- Overheating causes and cooling system pressure testing
- Clutch slipping diagnosis and plate wear inspection
- Gear jumping out of selected ratio and shift drum inspection
- Excessive chain/sprocket wear and final drive troubleshooting
- Abnormal engine noise top-end and bottom-end diagnosis
- WP suspension bottoming and damping adjustment guidance
- Electrical faults including no spark, intermittent firing, and charging issues
- Carburetor flooding, hesitation and flat spot tuning remedies
ILLUSTRATIONS & DIAGRAMS INCLUDED:
- Exploded views of complete engine assembly with part numbers
- Wiring diagrams for all model years
- Fuel system and carburetor cross-section illustrations
- Suspension assembly and linkage diagrams
- Frame geometry and chassis component illustrations
- Brake hydraulic system schematics
- Exhaust routing and mounting details
COMPATIBILITY:
- Covers KTM 625 SXC model years 1998, 1999, 2000, 2001, 2002, 2003
- Covers KTM 660 SMC model years within same period
- Applicable to all variants within these year ranges
- Service procedures align with Rotax 640/660 LC4-based engine family
FILE PROPERTIES:
- Format: Searchable PDF
- Language: English
- Delivery: Instant digital download
- Access: Download anytime after purchase
