1999–2006 KTM 125/200 Two-Stroke Engine Service & Repair Manual (P/N 3.206.031-E)

KTM publication Art. Nr. 3.206.031-E covers service and repair for the 1999–2006 125/200 liquid-cooled two-stroke range, including the SX, SXS, MXC, EGS, EXC, EXC Six Days, XC and XC-W configurations listed above. Additional sections address the 125 EXE, 125 Supermoto and 200 EGS Singapore.

Text search, navigation and wiring detail: Service text is searchable, with embedded bookmarks for chapters and subsections. Search is less reliable in older wiring diagrams, and some diagram lettering is not searchable. Small wiring labels require zooming; some older legends have faint lettering.

• Engine repair: Engine removal and installation, crankcase separation, crankshaft inspection, Nikasil cylinder checks, piston inspection and piston-ring end-gap measurements.

• Transmission and clutch: Mainshaft and countershaft service, shift-mechanism inspection, kickstarter repair, primary-drive removal, clutch wear checks and hydraulic clutch bleeding.

• Exhaust control: Power-valve disassembly, control-roller inspection, control-flap alignment and dimension Z adjustment, with model-specific setting data.

• Fuel systems: Keihin PWK carburetor disassembly and reassembly, float-level checks, altitude and temperature jetting charts, and separate-lubrication oil-pump adjustment.

• Electrical diagnostics: Kokusan 2K-1, 2K-2 and 2K-3 stator, pulse-generator and peak-voltage tests, supported by wiring diagrams and troubleshooting charts.

• Cooling and brakes: Water-pump disassembly, inspection and reassembly, cooling-system refilling, and front and rear brake-fluid replacement procedures.

This manual is suited to mechanics familiar with two-stroke engine repair who have the bearing-service tools and electrical test equipment required for the documented work.

Engine, Transmission and Clutch Repair

Technicians will find complete teardown and reassembly coverage for the engine housing, transmission, crankshaft and shift mechanism. Inspection data covers piston fitting clearance, crankshaft runout and clutch wear, with separate checks for the reed valve housing and intake flange.

Model differences: The manual distinguishes cylinder-head seals, shift-shaft arrangements, reed-valve components and five- versus six-speed transmission specifications. Dimension X addresses piston-to-cylinder height, while dimension Z sets the exhaust control flap.

Clutch release: Dimension Y relates slave-cylinder gasket thickness to the fitted push rod. Separate tables for the two push-rod versions help match the gasket to the installed hardware before clutch reassembly.

Exploded views show the clutch and transmission shafts. Listed workshop tools include clutch holder 503.29.003.000 and control-flap adjusting plate 503.29.022.000.

Carburetor Tuning and Separate Lubrication

The illustrated Keihin PWK 36S AG and PWK 38 AG/PWK 39 sections cover throttle-slide and jet-needle inspection, float-needle valve checks and carburetor assembly. Jetting charts distinguish model, market, altitude and temperature; the unrestricted EXC settings are marked for off-highway use.

The 125 EXE and 125 Supermoto specifications include Dell'Orto PHBH 28 settings. Their oil-pump adjustment references differ from other separate-lubrication versions, and the manual warns that incorrect adjustment can cause engine damage.

Ignition Tests and Wiring Diagrams

Electrical sections distinguish earlier ignition connections from later four-pin connectors. Test coverage includes the Shindengen regulator-rectifier, Kokusan voltage regulator, capacitor and ignition coil, with resistance specifications identified by wire color.

European EXC and 200 XC-W wiring diagrams show lighting, regulation and ignition connections. Peak-voltage test layouts identify the measurement points; CDI functional testing requires an ignition test bench, and resistance checks alone do not reveal every ignition fault.

The troubleshooting charts address starting problems, poor idle, power loss, high-rpm misfiring, overheating and excessive oil from the transmission breather.

Cooling, Brake Service and Maintenance Scope

Water-pump repair covers the shaft, bearing, seal and drive gear. The brake-fluid procedures specify DOT 5.1 and warn that silicone-based DOT 5 can damage brake hoses and seals.

Model-specific periodic maintenance schedules accompany engine and chassis torque tables, fluid capacities, gear ratios and wear limits. Fork and WP PDS shock information consists of specifications, adjustment settings and maintenance schedules; full internal suspension overhaul procedures are outside this manual's scope.

Working on high-performance two-stroke engines carries inherent safety risks. Always verify your mechanical capabilities and ensure you are using appropriate workshop equipment before initiating a major repair or teardown.

PDF Contents and Page Count

Supplied as one printable, English-language 186-page PDF: 1 cover page, 159 pages of service information, specifications and maintenance schedules, and a 26-page wiring-diagram section with its index and legends. All of these pages are included in the total.