2000 Yamaha YZ250F(N)/LC Owner's Service Manual (5NL-28199-30)

Yamaha’s YZ250F(N)/LC Owner’s Service Manual, first edition September 2000 (5NL-28199-30), covers operation, maintenance, repair, and tuning for the YZ250FN, YZ250FLC, and YZ250F(N) regional models.

• Engine repair: Engine removal, camshaft timing, valve and guide service, piston inspection, crankcase separation, crankshaft installation, and clutch and transmission repair.

• Carburetor service: Keihin FCR-MX37 disassembly, accelerator-pump inspection, float-height adjustment, starter-plunger service, and regional jetting references.

• Cooling and lubrication: Radiator and cooling-system pressure checks, water-pump seal replacement, oil-pump inspection, and dry-sump lubrication checks.

• Brakes and chassis: Caliper and master-cylinder rebuilding, hydraulic bleeding, wheel-bearing replacement, steering service, and swingarm-linkage inspection.

• Suspension and tuning: Fork disassembly and seal replacement, rear-shock spring and bearing service, damping adjustments, and symptom-based suspension-setting charts.

• Electrical diagnosis: Ignition and throttle-position-sensor troubleshooting, coil tests, sensor adjustment, wiring diagrams, and connector test illustrations.

The repair sections are suited to mechanics familiar with engine measurement and electrical testing; Yamaha recommends dealer maintenance for the front fork because of its sensitive internal construction.

Engine Internals and Valve Timing

The engine chapter extends from cylinder-head work to crankshaft and transmission removal. Valve service includes guide replacement, seat inspection and refinishing, spring checks, and a color-matching chart for cylinder heads and valve lifters. Separate intake and exhaust pad-selection tables support valve-clearance adjustment.

Camshaft handling: The manual warns that uneven camshaft-cap loosening or tightening can damage the cylinder head, caps, and camshafts. Timing-mark illustrations and tensioner checks accompany the installation procedure.

Clutch coverage distinguishes the friction-plate and steel-plate positions and includes spring and plate wear checks. Transmission procedures address gear dogs, shift forks, the shift cam, and operational checks after assembly. Exploded diagrams and job instruction charts identify the parts involved in each removal.

The special-tool list distinguishes regional tool numbers, including crankcase separator YU-1135-A/90890-01135 and clutch holding tool YM-91042/90890-04086.

FCR-MX37 Service and Race Settings

Carburetor procedures cover the accelerator-pump diaphragm and linkage, leak jet, float valve, and separate hot- and cold-start plungers. The tuning chapter relates jet and needle changes to throttle opening, atmospheric conditions, and running symptoms.

European and other-market needle specifications are distinguished, with setting-part numbers provided. Those distinctions help match replacement needles and tuning references to the regional carburetor before parts are selected.

The pilot-screw position shown in the manual is an example; the service text explains that each machine’s setting was established individually. Starting and break-in instructions also address the manual decompression system and hot-start operation.

Cooling and Dry-Sump Lubrication

Cooling coverage includes radiator-cap opening-pressure testing, system leak checks, radiator removal, and water-pump shaft, bearing, and seal inspection.

The lubrication sections explain oil-level checking at the frame reservoir, filter and strainer service, oil-pressure verification, and oil-pump rotor-clearance inspection. They distinguish routine oil changes from filter replacement and total system capacity.

Forks, Linkage, and Hydraulic Brakes

Fork service includes damper-rod removal, bushing and seal inspection, oil-level setting, and reassembly using the specified holder and seal driver. The assembly notes warn that dropping the damper rod into the inner tube can damage the internal valve.

Rear suspension coverage includes swingarm and relay-arm bearings, shock removal, spring replacement, and preload and damping adjustment. Rear-shock internal rebuilding is outside this section’s scope: Yamaha prohibits disassembly of the nitrogen-filled cylinder and reservoir. Follow the manual’s high-pressure nitrogen precautions; disposal is assigned to Yamaha dealers.

Regional spring specifications and the Suspension Setting charts address bottoming, harshness, poor grip, and front-to-rear balance. Brake procedures cover both master cylinders and calipers, seal replacement, hose installation, bleeding, and final leak checks.

CDI and Throttle-Position-Sensor Troubleshooting

The Wiring Diagram and Cable Routing Diagram support circuit tracing and harness installation. Separate Ignition System and Throttle Position Sensor System flowcharts connect symptoms with component checks, supported by connector illustrations and electrical test specifications.

The ignition checks cover the stop switch, ignition coil, magneto pickup and charging coils, and neutral switch before CDI replacement is considered. The map-controlled CDI explanation includes an illustrative 3-D ignition-timing map showing the control principle, rather than actual calibration data.

Examples of Valve and Piston Inspection Data

Cold valve-clearance specifications are 0.10–0.15 mm for the intake valves and 0.17–0.22 mm for the exhaust valves. These accompany the inspection procedure and separate pad-selection tables.

The cylinder-and-piston section specifies piston-to-cylinder clearance of 0.040–0.065 mm, with a 0.1 mm service limit. It also supplies the bore and piston measuring references used to assess that clearance.

Searchable Text, Diagram Detail, and PDF Contents

Search and diagram access: Searchable PDF text is available throughout the manual. Embedded language and chapter bookmarks lead to the cover and contents pages. Small wiring color codes and connector labels require zooming for comfortable reading.

Supplied as one 656-page printable PDF containing English, French, German, and Italian text. The total includes all language sections, 25 front-matter pages including the original cover, and one rear cover.