2000–2006 KTM 250 EXC Racing, 400/450/520/525/540/560/610 Engine Repair Manual (P/N 3.206.033-E)

This KTM repair manual, Art.-Nr. 3.206.033-E, Edition 02/2006, covers the listed 2000–2006 250–610 Racing four-stroke engines, including the 250 EXC Racing and 610 CRATE.

Text search and wiring detail: Repair text and specification tables are searchable, but several wiring diagrams lack searchable labels. Embedded bookmarks provide chapter and procedure navigation. Small wiring labels require zooming.

• Engine repair: Engine removal and refitting, crankcase separation, crankshaft and balancer-shaft service, cylinder-head overhaul, valve-guide replacement and timing-chain installation.

• Clutch and transmission: Clutch wear checks, hydraulic-clutch bleeding, shift-mechanism inspection, and separate mainshaft assembly procedures for four- and six-speed transmissions.

• Fuel system: Keihin FCR 35/39 and FCR-MX 37/39/41 carburetor overhaul, throttle-position-sensor testing and adjustment, idle adjustment and float-height checks.

• Lubrication and cooling: Oil-circuit schematic, rotor-pump and bypass-valve inspection, oil-filter and screen service, water-pump seals and cooling-system bleeding.

• Ignition and starting: Kokusan ignition diagnosis, static ignition tests, generator output checks, and starter-motor, starter-relay and regulator-rectifier testing.

• Service references: Model-specific wiring diagrams, troubleshooting charts, special-tool illustrations, torque tables, inspection limits and periodic maintenance schedules.

KTM assumes repairs will be performed by qualified, professionally trained mechanics and omits general workshop procedures.

Engine Documentation and Assembly

The internal repair sections cover piston and Nikasil cylinder measurements, crankshaft and transmission-shaft axial-clearance compensation, and rocker-arm setup. Valve-guide replacement distinguishes steel and titanium valve requirements and identifies the press-in tool 590.29.018.000 and reamer 590.29.018.050.

The crankshaft section warns that incorrectly aligned crankpin oil passages can starve the connecting-rod bearing and cause bearing damage. Camshaft and timing-chain sections cover automatic decompression, tensioner inspection, chain riveting and model-specific guide mounting.

Clutch, Transmission and Starter Drives

Clutch illustrations distinguish the early bearing-bush arrangement from later needle bearings, along with changes to clutch hubs and plate packs. These differences help match repair parts and wear checks to the actual engine configuration.

Transmission inspections cover gear teeth, shift dogs and shaft bearings. The 2006 450 SXS five-speed transmission appears in the specification tables; the assembly chapters describe four- and six-speed shafts.

Starter-drive coverage distinguishes the earlier reduction gear from the 2006 torque limiter and includes freewheel inspection.

Keihin Carburetor Repair

FCR and FCR-MX exploded views accompany accelerator-pump and float-needle inspection, hot-start checks and sensor adjustment. The manual distinguishes the FCR 35 installation on the 250 Racing from the FCR 39 used on the 400/520 and supplies model-specific jetting tables.

Oil Circuit and Water-Pump Service

The Oil Circuit schematic explains how the two rotor pumps supply the top end, crankshaft and transmission. Oil-service instructions specify Motorex Power Synt 4T.

Water-pump illustrations distinguish the seal-carrier designs, including the version removable without lifting the cylinder-head top section.

Electrical Diagnosis and Wiring Diagrams

Static ignition tests distinguish Kokusan 4K-3A and 4K-3B systems. Ignition-coil resistance and stator/pickup checks accompany the fault-finding procedures. Static and dynamic 4K-3B generator charts specify measurements using peak-voltage adapter 584.29.042.000.

CDI testing requires an ignition test bench; the manual warns that ordinary measuring devices can damage the electronics.

Region-specific wiring covers EXC, MXC/XC and SX/SXS/SMR layouts. The EXC/XC Desert diagrams include connector identifiers, pin numbers and separate CDI/starter and lighting, horn and instruments circuits.

Technical Specifications and Maintenance Data

Engine and chassis tables include fluid capacities, wear limits and torque specifications, with WP fork and PDS shock settings. Maintenance schedules distinguish routine checks from competition-related engine inspections.

Chassis coverage includes specifications and brake-fluid changes, but not full fork, shock or brake-caliper overhaul procedures. Observe the manual's precautions for hot fluids, fuel handling and brake service.

PDF Edition and Page Breakdown

One printable English PDF includes multilingual wiring legends. The 222-page file comprises 14 pages of front matter, 178 pages of service procedures, specifications and maintenance schedules, and a 30-page wiring-diagram section; all 20 blank pages and the two legend pages are already included in those totals.