Yamaha WR250F(T) User Manual

5PH-28199-30WR250F(N)OWNER’S SERVICE MANUALMANUEL D’ATELIER DUET PROPRIETAIREFAHRER- UNDWARTUNGS-HANDBUCHMANUALE DI SERVIZIO DELPROPRIETARIO

4 - 12ENGCARBURETORFloat height1. Measure:● Float height a Out of specification → Adjust.Float height:8.0 mm (0.31 in)Measurement and adjustment steps

4 - 13ENGStarter plunger1. Inspect:● Cold starter plunger 1 ● Hot starter plunger (red) 2 Wear/damage → Replace.Accelerator pump1. Inspect:● Diaphragm

4 - 14ENGCARBURETOR2. Install:● Main air jet 1 ● Pilot air jet 2 ● Intake joint 3 T R..5 Nm (0.5 m · kg, 3.6 ft · lb)3. Install:● Spring 1 1 ● Lever 1

4 - 15ENGCARBURETOR7. Install:● Spring 1 ● Joint collar 2 To throttle shaft 3.NOTE:Install the bigger hook a of the spring fits onthe stopper b of the

4 - 16ENGCARBURETOR10.Install:● Starter jet 1 ● Pilot jet 2 ● Spacer 3 ● Needle jet 4 ● Main jet 5 11.Install:● Valve seat● Screw (valve seat) 1 ● Nee

4 - 17ENGCARBURETOR14.Install:● Diaphragm (air cut valve) 1● Spring (air cut valve) 2● O-ring 3● Air cut valve cover 4● Screw (air cut valve cover) 5

4 - 18ENGCARBURETOR19.Install:● Carburetor breather hose 1 NOTE:Install the carburetor breather hoses to thecarburetor so that the hoses do not bend n

4 - 19ENG5. Install:● Throttle cable cap 1 16. Install:● Throttle cable 1 7. Adjust:● Throttle grip free playRefer to “THROTTLE CABLE ADJUST-MENT” sec

–+ELEC6 - 7THROTTLE POSITION SENSOR SYSTEMTHROTTLE POSITION SENSOR SYSTEMINSPECTION STEPSIf the throttle position sensor will not operate, use the fol

6 - 8–+ELECTHROTTLE POSITION SENSOR SYSTEMEC624000COUPLERS AND LEADS CONNECTION INSPECTION1. Check:● Couplers and leads connectionRust/dust/looseness/

3 - 10INSPADJTHROTTLE CABLE ADJUSTMENTTHROTTLE CABLE ADJUSTMENT1. Check:● Throttle grip free play a Out of specification → Adjust.Throttle grip free p

6 - 9–+ELECTHROTTLE POSITION SENSOR SYSTEMTHROTTLE POSITION SENSOR REPLACEMENT AND ADJUSTMENT1. Remove:● Throttle position sensor coupler● Screw (thro

6 - 10–+ELECTHROTTLE POSITION SENSOR SYSTEM6. Adjust:● Throttle position sensor coil resistanceat idle speedAdjustment steps:Adjust the angle of the t

7 - 1TUN EC700000 TUNING EC710000 ENGINE Carburetor setting ● The air/fuel mixture will vary depending onatmospheric conditions. Therefore, it is nec

7 - 2TUNCAUTION: ● The carburetor is extremely sensitive toforeign matter (dirt, sand, water, etc.).During installation, do not allow foreignmatter t

7 - 3TUN SETTING Effects of the setting parts on the throttle valve opening Å Closed ı Fully open 1 Pilot screw/pilot jet 2 Throttle valve cutaway 3

7 - 4TUN SETTING 1 Jet needle 2 Main air jet 3 Pilot air jet 4 Needle jet 5 Main jet 6 Pilot jet 7 Pilot screw Main jet adjustment The richness of th

7 - 5TUN SETTING Pilot screw adjustment The richness of the air-fuel mixture with thethrottle fully closed to 1/4 open can be set byturning the pilot

7 - 6TUN SETTING Effects of adjusting the pilot jet (reference) Å Idle ı Fully open1/4 1/2 3/4+5%–5%#45#40#42Åı Jet needle groove position adjustment

7 - 7TUNJet needle adjustmentThe jet needle is adjusted by changing it.* For EUROPE** For CDN, ZA, AUS and NZThe tapered sections of all jet needles h

7 - 8TUNEffects of changing the jet needle (reference)(Diameter of the straight portion)Changing the diameter of the straight portionadjusts the air-f

3 - 11INSPADJTHROTTLE LUBRICATION/DECOMPRESSION ADJUSTMENTTHROTTLE LUBRICATION1. Remove:● Rubber cover 1● Throttle grip cap 2 2. Apply:● Lithium soap

7 - 9TUNSETTINGEC71Q000Carburetor setting parts* For EUROPE** For CDN, ZA, AUS and NZPart name Size Part numberMain jet Rich(STD)Lean#185#182#180#178

7 - 10TUNExamples of carburetor setting depending on symptomThis should be taken simply for an example. It is necessary to set the carburetor while ch

PRINTED IN JAPAN2000 · 11 - 2.5 × 1 CRPRINTED ON RECYCLED PAPER YAMAHA MOTOR CO., LTD.2500 SHINGAI IWATA SHIZUOKA JAPAN

3 - 19INSPADJENGINE IDLING SPEED ADJUSTMENT1. Start the engine and thoroughly warm itup.2. Attach:● Inductive tachometerTo spark plug lead.3. Adjust:●

4 - 7ENGCARBURETORCARBURETORExtent of removal: 1 Carburetor removalExtent of removal Order Part name Q’ty RemarksCARBURETOR REMOVALPreparation for rem

4 - 8ENGCARBURETOREC468000CARBURETOR DISASSEMBLYExtent of removal: 1 Carburetor disassemblyExtent of removal Order Part name Q’ty RemarksCARBURETOR DI

4 - 9ENGCARBURETORExtent of removal Order Part name Q’ty RemarksG Float 1H Needle valve 1I Valve seat 1J Main jet 1K Needle jet 1L Spacer 1M Pilot jet

4 - 10ENGCARBURETORHANDLING NOTECAUTION:Do not loosen the screws (throttle positionsensor) 1 except when changing the throt-tle position sensor due to

4 - 11ENGCARBURETOR2. Inspect:● Main jet 1 ● Pilot jet 2 ● Needle jet 3 ● Starter jet 4 ● Main air jet 5 ● Pilot air jet 6 ● Leak jet 7 Damage → Repla