Target Audience:
Professional technicians, KTM service departments, and DIY owners performing engine rebuilds and part replacement
Manual Purpose:
Factory parts identification for engine replacement and rebuild work on the LC4 platform
Key Advantage:
Complete OEM parts breakdowns with factory part numbers, ensuring correct ordering and fitment
Scope:
Full engine coverage for the 400 and 640 LC4 single-cylinder models in one catalog
Coverage Areas:
Complete LC4 engine — all components, assemblies, and hardware with exploded-view diagrams
Manual Type:
OEM replacement parts catalog
File Format:
Searchable PDF — zoomable, printable, bookmarked chapters
Delivery Method:
Instant digital download, no shipping required
Device Compatibility:
Windows PC, Mac, tablets, smartphones
Access:
Download again anytime after purchase
Engine Block and Cases:
Cylinder block, crankcases, covers, and gaskets with part numbers
Cylinder Head:
Head, valves, camshaft, rocker arms, and related hardware
Piston and Cylinder:
Pistons, rings, pins, clips, and cylinder assemblies
Crankshaft and Connecting Rod:
Crank assembly, rods, bearings, and seals
Ignition System:
Stator, rotor, CDI components, and spark plug fittings
Clutch:
Clutch basket, plates, springs, and actuation parts
Transmission Internals:
Gear sets, shafts, shift drums, and forks where included in engine catalog
Lubrication System:
Oil pump, filters, lines, and seals
Cooling System (LC4):
Radiator, hoses, water pump components for liquid-cooled variants
Carburetion / Fuel Delivery:
Carburetor fittings, intake components, and fuel tap parts
Electrical Components:
Wiring, switches, and connectors associated with the engine
Fasteners and Hardware:
Bolts, nuts, washers, and special screws throughout the engine
Exploded-View Diagrams:
Detailed parts diagrams for every engine assembly
OEM Part Numbers:
Factory part numbers listed for each component
Component Identification:
Location guides and reference numbering
Torque Specifications:
Factory torque values referenced for assembly hardware
Special Tools:
Special service tool numbers with illustrations
Depth Level:
Parts-level detail suitable for correct ordering and engine rebuild planning
Model Applicability:
All 400 and 640 LC4 engine variants for 1998 — refer to catalog for specific variant applicability
File Format:
PDF (searchable, bookmarked, zoomable)
Compatibility:
Windows, macOS, Linux, iOS, and Android — any device with a PDF reader
Requirements:
A PDF reader application (e.g. Adobe Acrobat Reader, free)
Searchability:
Fully text searchable for fast lookup of any topic
Print Quality:
High-resolution digital pages, printable at full clarity
Binding Type:
N/A — digital download, no physical binding
Paper Type:
N/A — digital download, no physical paper
Primary Engine:
KTM LC4 single-cylinder 4-stroke
Engine Options Range:
400 LC4 and 640 LC4 displacements
Configuration:
Single cylinder, liquid-cooled (LC), 4-valve SOHC (640 LC4)
Fuel System:
Carburetor (Keihin type per LC4 factory fitment)
Cooling:
Liquid-cooled with radiator and water pump
Detailed Specs:
N/A - refer to manual for detailed displacement and performance figures per variant
Ignition:
Electronic CDI ignition system
Instrumentation:
Basic analog gauge cluster, model dependent
Infotainment:
N/A - not applicable to this motorcycle
Driver Assistance:
N/A - not applicable to this motorcycle
Maintenance Schedules:
Factory maintenance schedules included in accompanying service documentation
Fluid Specifications:
Engine oil and coolant specifications referenced per factory requirements
Wear Items:
Pistons, rings, clutch plates, valves, seals, and bearings — all covered with part numbers
Torque Values:
All factory torque specs included for fasteners
