1999–2010 KTM 125–200 2-Stroke Engine SX, SXS, MXC, EGS, EXC, XC, and XC-W series OEM Service Manual (P/N 3.206.062-E)

This KTM factory engine repair manual covers the 1999–2010 125/144/150/200 two-stroke range in SX, SXS, MXC, EGS, EXC, EXC SIX DAYS, XC and XC-W configurations. Publication 3.206.062-E is the July 2009 edition with integrated updates.

• Engine repair: Engine removal and installation, crankcase separation, crankshaft and Nikasil cylinder inspection, bearing replacement and water-pump overhaul.

• Transmission and clutch: Mainshaft and countershaft assembly views, shift-mechanism inspection, clutch wear checks, hydraulic clutch bleeding and kickstarter service.

• Exhaust control: Control-flap and centrifugal mechanism inspection, cylinder assembly, and dimension X/Z adjustment references.

• Carburetors: Removal, disassembly, float-level inspection and reassembly for the illustrated Keihin PWK units, plus temperature- and altitude-based jetting charts.

• Electrical diagnosis: Kokusan ignition and generator tests, Shindengen regulator-rectifier checks, capacitor and ignition-coil testing, and model-specific wiring diagrams.

• Chassis reference: Brake-fluid replacement procedures, WP baseline settings, chassis torque tables and model-specific maintenance schedules.

KTM wrote this manual for qualified, professionally trained mechanics and assumes familiarity with standard workshop procedures.

Engine Maintenance and Complete Teardowns

The engine-removal notes distinguish work that can be done in the frame, including cylinder, clutch and primary-drive service, from a complete teardown. That distinction helps a shop plan how far a repair needs to go.

The cylinder section pairs Nikasil bore inspection with piston-sizing data and ring checks. Crankshaft inspection covers journal runout and crank-web dimensions. Dimension X addresses piston-to-cylinder height at top dead center, while dimension Z establishes the exhaust-control flap position.

Crankcase-separation cautions explain how levering between the housings can damage their sealing surfaces. The special-tool reference identifies the control-flap adjusting plate, 503.29.022.000, and Kokusan rotor extractor, 546.29.009.044.

Engine and brake work involves moving components and pressurized systems; follow the manual’s warnings and established workshop safety practices.

Clutch, Transmission and Water-Pump Service

The clutch exploded view distinguishes the friction, aluminum and steel discs. Separate gasket-selection tables address the original and revised clutch pushrods, while the transmission sections show gear identification marks, shaft layouts and shift-fork inspection points.

Water-pump repair extends to the shaft seal, bearing and drive wheel. Models with separate lubrication have their own oil-pump installation and adjustment notes.

Keihin Carburetors and Model-Specific Fuel Settings

Keihin PWK 36S AG, PWK 38AG and PWK 39 procedures cover the jets, throttle slide, starting piston, float needle valve and gaskets. Later specification tables also identify the PWK-S 38 AG.

Temperature and altitude charts distinguish model, market and carburetor settings. The 125 EXE and 125 Supermoto specification pages list Dell’Orto PHBH 28 settings; the illustrated carburetor overhaul procedures cover the Keihin units.

Kokusan Ignition Tests and Wiring Diagrams

Kokusan 2K-1, 2K-2 and 2K-3 sections combine resistance checks with peak-voltage adapter tests and their measuring conditions. Wiring examples include regional 125/200 EXC circuits, 125 EXE/125 Supermoto diagrams and SX/SXS ignition layouts, with component keys and cable-color legends.

CDI testing requires an ignition test bench; the manual warns that conventional measuring equipment can damage the unit.

Troubleshooting charts connect starting problems, poor power, overheating and white exhaust smoke with possible causes and checks.

WP Setup Data, Brake Service and Maintenance Schedules

WP fork and PDS shock tables provide baseline adjustments and chassis specifications rather than suspension overhaul procedures. Maintenance schedules distinguish competition and hobby use where applicable.

Front and rear brake-fluid replacement is described. The brake-pad and disc-inspection entry directs the reader to the owner’s manual.

A Sample of Clutch Wear Limits and Charging-Test Data

These examples are a small selection of the inspection limits and electrical test specifications in the manual.

The clutch inspection section lists a minimum friction-disc thickness of 2.9 mm.

The Shindengen regulator-rectifier check specifies 14.0–15.0 V at 5,000 rpm with the low beam switched on.

Searchable Repair Text, Bookmarks and Wiring Detail

Text search and diagram navigation: Main repair text is searchable, while some maintenance-table text and wiring labels fall outside the searchable text layer. Embedded bookmarks cover chapters and many subsections, although some wiring-diagram links select the wrong variant. Small wiring labels require zooming for comfortable reading.

The 280-page printable PDF is supplied as one file, with English repair text and multilingual wiring legends. The total already includes seven pages of front matter and 25 blank pages.