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Yamaha MX775 Service Manual
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Yamaha MX775 Service Manual

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SERVICE MANUAL
MX775
MX800
MX825
LIT-19616-02-37
7UD-F8197-E0

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Summary of Contents for Yamaha MX775

  • Page 1 SERVICE MANUAL MX775 MX800 MX825 LIT-19616-02-37 7UD-F8197-E0...
  • Page 3 MX775, MX800, MX825 SERVICE MANUAL ©2016 by Yamaha Motor Corporation, U.S.A. 1st Edition, December 2016 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Corporation, U.S.A. is expressly prohibited. LIT-19616-02-37...
  • Page 4 This manual was produced by the Yamaha Motor Powered Products Co., Ltd. primarily for use by Yamaha dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one manual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha machines should have a basic understanding of mechanics and the techniques to repair these types of machines.

  • Page 5: How To Use This Manual

    HOW TO USE THIS MANUAL This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive explanations of all installation, removal, disassembly, assembly, repair and check procedures are laid out with the individual steps in sequential order. •...
  • Page 6 SYMBOLS The following symbols are used in this manual for easier understanding. The following symbols are not relevant to every machine. SYMBOL DEFINITION SYMBOL DEFINITION Filling fluid Lubricant Special tool Tightening torque Wear limit, clearance Engine speed Electrical data Replace the part with a new one. Lithium-soap base grease Molybdenum disulfide grease Engine oil...
  • Page 7 INDEX GENERAL INFORMATION PERIODIC CHECKS AND ADJUSTMENTS ENGINE FUEL ELECTRICAL TROUBLESHOOTING SPECIFICATIONS...
  • Page 8 MEMO...

  • Page 9: Table Of Contents

    TABLE OF CONTENTS OIL COOLER ........2-9 GENERAL INFORMATION AIR FILTER ELEMENT ......2-9 ADJUSTING THE VALVE MACHINE IDENTIFICATION ......1-1 CLEARANCE ........2-9 SERIAL NUMBER .........1-1 CYLINDER HEADS STARTING SERIAL NUMBER....1-1 DECARBONIZATION ......2-13 ENGINE SPEED ......... 2-14 DIMENSIONS ..........1-2 ADJUSTING THE ENGINE SPEED..
  • Page 10 CYLINDER HEAD COVERS, CYLINDER INSTALLING THE FLYWEIGHT HEADS............3-20 SHAFT ASSEMBLY AND CYLINDER HEAD #1 ......3-20 GOVERNOR FORK ......3-42 CYLINDER HEAD #2 ......3-22 REMOVING THE CAMSHAFT AND CHECKING THE ROCKER ARMS VALVE LIFTERS ......... 3-43 AND ROCKER ARM SHAFTS.....3-24 CHECKING THE CAMSHAFT .... 3-43 CHECKING THE PUSH RODS ...3-24 CHECKING THE VALVE LIFTERS ..
  • Page 11 FUEL INJECTORS AND INTAKE CHECKING THE STATOR COIL MANIFOLD ..........4-9 ASSEMBLY ......... 5-34 REMOVING THE FUEL CHECKING THE RECTIFIER/ INJECTORS ........4-11 REGULATOR ........5-35 INSTALLING THE FUEL CHECKING THE FUEL INJECTORS ........4-12 INJECTORS........5-35 REMOVING THE MANIFOLD CHECKING THE STARTER MOTOR ABSOLUTE PRESSURE SENSOR ..4-14 OPERATION ........
  • Page 12 GENERAL TORQUE SPECIFICATIONS ........7-10 LUBRICATION POINTS AND TYPE OF LUBRICANTS...........7-11 WIRE ROUTING DIAGRAM .....7-12 UPPER SIDE VIEW......7-12 LEFT SIDE VIEW ........7-16 RIGHT SIDE VIEW......7-18 REAR SIDE VIEW .......7-22...

  • Page 13: General Information

    GENERAL INFORMATION MACHINE IDENTIFICATION SERIAL NUMBER The serial number is printed on the label “1” affixed to the position of the multi-purpose engine as shown in the illus- tration. • The first four digits identify the model, and the remaining digits indicates the production number.

  • Page 14: Dimensions

    DIMENSIONS DIMENSIONS mm (in) MOUNTING BASE mm (in) 3/8-16UNC *1: UNC: Unified coarse thread (Unit: in) *2: PCD: Pitch Circle Diameter...

  • Page 15: Rear

    DIMENSIONS REAR mm (in) 463.8(18.26) 231.1(9.1) REAR (For models equipped with a muffler) mm (in) 463.8(18.26) 231.1(9.1) 445.4(17.54)

  • Page 16: Right Side

    DIMENSIONS RIGHT SIDE mm (in) RIGHT SIDE (For models equipped with a muffler) mm (in)

  • Page 17: Important Information

    Be sure to use the correct special tool for the job to guard against damage. Oil, grease and seals Be sure to use genuine Yamaha oils, grease and sealers, or the equivalents. Expendable parts Always replace the gaskets, O-rings, cotter pins and cir-...

  • Page 18: All Replacement Parts

    • Make sure that the parts, move smoothly after each sec- tion of the machine is assembled. ALL REPLACEMENT PARTS We recommend the use of genuine Yamaha parts for all replacements. Use oil and/or grease, recommended by Yamaha, for assembly and adjustment.

  • Page 19: Bearings And Oil Seals

    BASIC SERVICE INFORMATION BEARINGS AND OIL SEALS Install the bearing(s) “1” and oil seal(s) “2” with their manu- facture’s marks or numbers facing outward. (In other words, the stamped letters must be on the side exposed to view.) When installing oil seal(s), apply a light coating of lightweight lithium base grease to the seal lip(s).
  • Page 20 BASIC SERVICE INFORMATION Checking the connections Check the leads, couplers, and connectors for stains, rust, moisture, etc. Disconnect: • Lead • Coupler • Connector NOTICE • When disconnecting a coupler, release the coupler lock, hold both sections of the coupler securely, and then disconnect the coupler.
  • Page 21 BASIC SERVICE INFORMATION Connect: • Lead • Coupler • Connector • When connecting a coupler or connector, push both sec- tions of the coupler or connector together until they are connected securely. • Make sure all connections are tight. Check: •...
  • Page 22 BASIC SERVICE INFORMATION Check: • Resistance Model 88 Multimeter with tachometer: YU-A1927 The resistance values shown were obtained at the stan- dard measuring temperature of 20 C (68 F). If the mea- suring temperature is not 20 C (68 F), the specified measuring conditions will be shown.

  • Page 23: Special Tools And Testers

    SPECIAL TOOLS AND TESTERS SPECIAL TOOLS AND TESTERS The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or improvised techniques. Valve spring compressor Ignition checker FI Diagnostic Tool...
  • Page 24 SPECIAL TOOLS AND TESTERS MEMO 1-12...

  • Page 25: Periodic Checks And Adjustments

    Check leaks and anything operator notices  such as noises or abnormal operation. *1 For models equipped with a Yamaha muffler. *2 Items marked with an asterisk require special tools, data and technical skills, have a Yamaha dealer perform the service.

  • Page 26: Periodic Maintenance

    PERIODIC MAINTENANCE PERIODIC MAINTENANCE SPARK PLUGS WARNING Check and adjust the areas around the cylinder head after the engine has cooled down completely. Remove: • Spark plug caps “1” • Spark plugs NOTICE Before removing the spark plugs, use compressed air to clean the cylinder head covers to prevent dirt from falling into the engine.

  • Page 27: Muffler

    PERIODIC MAINTENANCE Install: • Spark plugs Spark plug: 20 N·m (2.0 kgf·m, 14 lb·ft) To prevent threads from being damaged, temporally tighten “a” the spark plug before tightening it to the speci- fied torque “b”. MUFFLER (For models equipped with a muffler) WARNING The engine and muffler will be very hot after the engine has been run.

  • Page 28: Engine Oil Leakage

    PERIODIC MAINTENANCE Remove: • Muffler (Refer to “MUFFLER (For models equipped with a muffler)” on page 3-4) Decarbonize: • Muffler Tap on the muffler in the area shown in the illustra- tion to loosen carbon buildup, and then shake it out from the end of the muffler.

  • Page 29: Engine Oil Level

    PERIODIC MAINTENANCE Check the areas outside of the engine for oil leakage. Oil leakage  Replace the gasket, oil seal, or O-ring. ENGINE OIL LEVEL Remove: • Oil filler cap “1” Check: • Check that engine oil is at the specified level. ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼...

  • Page 30: Replacing The Engine Oil

    PERIODIC MAINTENANCE Oil warning light comes on  Add oil. Oil warning light does not comes on  OK REPLACING THE ENGINE OIL WARNING Avoid draining the engine oil immediately after stop- ping the engine. The oil is hot and should be handled with care to avoid burns.
  • Page 31 PERIODIC MAINTENANCE c. Tighten the new oil filter to specification with an oil filter wrench. Oil filter: 14 N·m (1.4 kgf·m, 10 lb·ft) ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ Install: • Oil drain bolt gasket “1” • Oil drain bolt “2” Oil drain bolt: 27 N·m (2.7 kgf·m, 20 lb·ft) Fill: •...

  • Page 32: Fuel Leakage

    PERIODIC MAINTENANCE FUEL LEAKAGE Check: • Leakage Check at fuel pump, fuel hose, and throttle body. NOTICE Replace fuel hose every four years. FUEL FILTER WARNING Do not smoke, and keep away from open flames, sparks, or any other source of fire when handling or in the vicinity of fuel.

  • Page 33: Oil Cooler

    PERIODIC MAINTENANCE OIL COOLER Check: • Oil cooler Damage  Replace. Dirt/clog  Clean. AIR FILTER ELEMENT NOTICE Be sure not to run the engine without air filter element. Otherwise this can result in excessive piston and/or cylinder wear. Remove: •...
  • Page 34 PERIODIC MAINTENANCE Remove: • Cylinder head cover “3” • Cylinder head cover gasket Remove: • Fan case cover “1” (Refer to “CASE AND FAN” on page 3-11) • Grass screen “2” (Refer to “CASE AND FAN” on page 3-11) Turn the crankshaft clockwise, and then set the piston at TDC (top-dead-center) on the compression stroke.
  • Page 35 PERIODIC MAINTENANCE Valve clearance (cold): Normal ENG operation range (between 1000 hr periodic maintenance): Intake: 0.02–0.2 mm (0.0008–0.01 in) Exhaust: 0.02–0.2 mm (0.0008–0.01 in) Original set value (adjust at 1000 hr peri- odic maintenance): Intake: 0.07–0.13 mm (0.003–0.005 in) Exhaust: 0.07–0.13 mm (0.003–0.005 in) Adjust: •...
  • Page 36 PERIODIC MAINTENANCE c. Check the thickness of the current adjusting pad. The thickness of each adjusting pad is indicated in 1/100 mm units “a” and inscribed on the side. Example: If the adjusting pad is marked “180”, the pad thick- ness is 1.80 mm (0.071 in).

  • Page 37: Cylinder Heads Decarbonization

    PERIODIC MAINTENANCE g. Install the rocker arm “5”. (Refer to “CYLINDER HEAD COVERS, CYLINDER HEADS” on page 3-20) Rocker arm shaft bolt: 4.0 N·m (0.40 kgf·m, 2.9 lb·ft) • Lubricate the rocker arm with engine oil. • Turn the crankshaft clockwise several full turns to seat the parts.

  • Page 38: Engine Speed

    PERIODIC MAINTENANCE ENGINE SPEED Warm up the engine for several minutes. Connect: • FI Diagnostic Tool “1” FI Diagnostic Tool: 90890-03253 Measure: • High engine speed (with no load) Out of specification  Adjust. High engine speed (with no load): 3550–3600 r/min ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼...

  • Page 39: Adjusting The Engine Speed

    PERIODIC MAINTENANCE b. Check the low engine speed. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ ADJUSTING THE ENGINE SPEED Warm up the engine for several minutes. Connect: • FI Diagnostic Tool “1” FI Diagnostic Tool: 90890-03253 Adjust: • High engine speed ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Move the throttle lever “1” to the high engine speed position “a”.

  • Page 40: Fittings And Fasteners

    PERIODIC MAINTENANCE ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Move the throttle lever “1” to the low engine speed position “a”. b. Turn the screw “3” in direction “c” or “d” until obtain adequet low engine speed. Direction “c” Low engine speed is decreased. Direction “d” Low engine speed is increased.

  • Page 41: Engine

    ENGINE ENGINE INSPECTION MEASURING THE COMPRESSION PRESSURE The following procedure applies to all of the cylinders. Measure the compression pressure after checking and adjusting the valve clearance. Warm up the engine for several minutes. Remove: • Spark plug cap • Spark plug NOTICE Before removing the spark plug, use compressed air to clean the cylinder head cover to prevent dirt from...
  • Page 42 ENGINE INSPECTION ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. If the compression pressure is below the minimum specification, pour a teaspoonful of engine oil into the spark plug hole and measure again. Refer to the following table. Reading Diagnosis Higher than • Worn cylinder, piston, and piston ring(s) without oil •...

  • Page 43: Air Filter

    AIR FILTER AIR FILTER 1.8 N ・ m (0.18 kgf ・ m, 1.3 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 1.8 N ・...

  • Page 44: Muffler (For Models Equipped With A Muffler)

    MUFFLER (For models equipped with a muffler) MUFFLER (For models equipped with a muffler) 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) 18 N ・ m (1.8 kgf ・ m, 13 lb ・ ft) 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) 3.5 N ・...

  • Page 45: Oil Cooler

    OIL COOLER OIL COOLER 14 N ・ m (1.4 kgf ・ m, 10 lb ・ ft) 9 N ・ m (0.9 kgf ・ m, 6.5 lb ・ ft) 17 N ・ m (1.7 kgf ・ m, 12 lb ・ ft) 62 N ・...

  • Page 46: Removing The Oil Cooler

    OIL COOLER REMOVING THE OIL COOLER Remove: • Hose clamp (Clic-R) “1” • Remove the hose clamp using the hose clamp pliers “2”. • When removing the hose clamp, make sure that the thick tip “a” of the hose clamp pliers is directed as shown in the illustration.
  • Page 47 OIL COOLER • Make sure the oil seal is positioned properly. • Align the projection “a” on the adapter with the hole “b” in the crankcase cover 2. Install: • Oil filter • Oil hose 2 • Oil hose 1 •...

  • Page 48: Ecu, Rectifier/Regulator, And Fuses

    ECU, RECTIFIER/REGULATOR, AND FUSES ECU, RECTIFIER/REGULATOR, AND FUSES 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) 7 N ・...

  • Page 49: Installing The Fuses

    ECU, RECTIFIER/REGULATOR, AND FUSES INSTALLING THE FUSES Install: • 30 A fuse “1” • 10 A fuses “2” NOTICE For the 30 A fuse “1”, there is identification red tape “a” on the wire harness.

  • Page 50: Ignition Coils

    IGNITION COILS IGNITION COILS 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) Order Job/Parts to remove Q’ty...

  • Page 51: Case And Fan

    CASE AND FAN CASE AND FAN 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 7 N ・...

  • Page 52: Removing The Case And Fan

    CASE AND FAN REMOVING THE CASE AND FAN Remove: • Air filter case (Refer to “AIR FILTER” on page 3-3) Remove: • ECU and rectifier/regulator (Refer to “ECU, RECTIFIER/REGULATOR, AND FUSES” on page 3-8) Remove: • Low-pressure fuel pump (Refer to “FUEL PUMPS” on page 4-1) Remove: •...

  • Page 53: Checking The Case And Fan

    CASE AND FAN CHECKING THE CASE AND FAN Check: • Fan case cover “1” • Grass screen “2” • Fan case “3” • Fan “4” Damage  Replace. Dirt/clog  Clean. INSTALLING THE CASE AND FAN Install: • Fan “1” •...
  • Page 54 CASE AND FAN Insert the tab “a” of the fan case cover “4” into the hole “b” of the fan case “2” first and then install. Install: • Oil filler pipe • Oil filler pipe bolt Oil filler pipe bolt: 7 N·m (0.7 kgf·m, 5.1 lb·ft) •...

  • Page 55: Flywheel And Stator Coil Assembly

    FLYWHEEL AND STATOR COIL ASSEMBLY FLYWHEEL AND STATOR COIL ASSEMBLY 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 180 N ・ m (18 kgf ・ m, 130 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) Order Job/Parts to remove Q’ty...

  • Page 56: Removing The Flywheel And Stator Coil Assembly

    FLYWHEEL AND STATOR COIL ASSEMBLY REMOVING THE FLYWHEEL AND STATOR COIL ASSEMBLY Remove: • Air filter case (Refer to “AIR FILTER” on page 3-3) Remove: • ECU and rectifier/regulator (Refer to “ECU, RECTIFIER/REGULATOR, AND FUSES” on page 3-8) Remove: • Low-pressure fuel pump (Refer to “FUEL PUMPS”...

  • Page 57: Checking The Flywheel And Stator Coil Assembly

    FLYWHEEL AND STATOR COIL ASSEMBLY Remove: • Flywheel “1” • Woodruff key • Remove the flywheel “1” using the heavy duty puller “2”. • Fully tighten the tool holding bolts, making sure the tool body is parallel with the flywheel. If necessary, one bolt may be backed out slightly to level the tool body.
  • Page 58 FLYWHEEL AND STATOR COIL ASSEMBLY Install: • Washer “1” • Flywheel nut “2” Flywheel nut: 180 N·m (18 kgf·m, 130 lb·ft) Tighten the flywheel nut “2” using the primary clutch holder “3” to hold the flywheel. Primary clutch holder: YU-01235 Rotor holding tool: 90890-01235 Install:...

  • Page 59: Installing The Crankshaft Position Sensor

    FLYWHEEL AND STATOR COIL ASSEMBLY INSTALLING THE CRANKSHAFT POSITION SENSOR Install: • Crankshaft position sensor • Crankshaft position sensor bolts Crankshaft position sensor bolt: 7 N·m (0.7 kgf·m, 5.1 lb·ft) Measure: • Crankshaft position sensor air gap Out of specification  Adjust. Feeler gauge set: YU-26900-9 Crankshaft position sensor air gap:...

  • Page 60: Cylinder Head Covers, Cylinder Heads

    CYLINDER HEAD COVERS, CYLINDER HEADS CYLINDER HEAD COVERS, CYLINDER HEADS CYLINDER HEAD #1 11 N ・ m (1.1 kgf ・ m, 8.0 lb ・ ft) 4.0 N ・ m (0.40 kgf ・ m, 2.9 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 12 N ・...
  • Page 61 CYLINDER HEAD COVERS, CYLINDER HEADS 11 N ・ m (1.1 kgf ・ m, 8.0 lb ・ ft) 4.0 N ・ m (0.40 kgf ・ m, 2.9 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 12 N ・...

  • Page 62: Cylinder Head #2

    CYLINDER HEAD COVERS, CYLINDER HEADS CYLINDER HEAD #2 11 N ・ m (1.1 kgf ・ m, 8.0 lb ・ ft) 4.0 N ・ m (0.40 kgf ・ m, 2.9 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 12 N ・...
  • Page 63 CYLINDER HEAD COVERS, CYLINDER HEADS 11 N ・ m (1.1 kgf ・ m, 8.0 lb ・ ft) 4.0 N ・ m (0.40 kgf ・ m, 2.9 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 12 N ・...

  • Page 64: Checking The Rocker Arms And Rocker Arm Shafts

    CYLINDER HEAD COVERS, CYLINDER HEADS CHECKING THE ROCKER ARMS AND ROCKER ARM SHAFTS The following procedure applies to all of the rocker arms and rocker arm shafts. Check: • Rocker arm “1” • Rocker arm shaft “2” Wear/damage/cracks  Replace. CHECKING THE PUSH RODS The following procedure applies to all of the push rods.

  • Page 65: Installing The Cylinder Head Assembly

    CYLINDER HEAD COVERS, CYLINDER HEADS Check: • Cylinder head combustion chamber Check the combustion chamber for carbon depos- its. Any carbon deposits  Eliminate. Be sure not to damage the sealing surface of the cylinder head. Check: • Cylinder head Cracks/damage around the hole of spark plug ...
  • Page 66 CYLINDER HEAD COVERS, CYLINDER HEADS Cylinder head bolt: 1st: 12 N·m (1.2 kgf·m, 8.7 lb·ft) 2nd: 50 N·m (5.0 kgf·m, 36 lb·ft) 3-26...

  • Page 67: Valves

    VALVES VALVES Order Job/Parts to remove Q’ty Remarks Remove the parts in the order listed. Removing the valves The following procedure applies to both cylin- ders. Refer to “CYLINDER HEAD COVERS, CYL- Cylinder head assembly INDER HEADS” on page 3-20. Valve cotter Valve spring retainer Intake valve spring...

  • Page 68: Removing The Valves And Valve Springs

    VALVES REMOVING THE VALVES AND VALVE SPRINGS The following procedure applies to all of the valves, valve springs and related components. Remove: • Valve cotter “1” • Valve spring retainer “2” • Valve spring “3” • Valve stem seal “4” •...
  • Page 69 VALVES Measure: • Valve stem diameter “a” Valve stem diameter (Intake): 5.948–5.963 mm (0.2342–0.2348 in) Valve stem diameter (Exhaust): 5.940–5.955 mm (0.2339–0.2344 in) Limit (Intake): 5.918 mm (0.2330 in) Limit (Exhaust): 5.910 mm (0.2327 in) Out of specifications  Replace. Measure: •...

  • Page 70: Checking The Valve Seats

    VALVES Installed compression spring force (Intake): 67.7 N (6.90 kgf, 15.2 lbf) Installed compression spring force (Exhaust): 118.1 N (12.0 kgf, 26.5 lbf) Installed length (Intake): 29.3 mm (1.1535 in) Installed length (Exhaust): 29.0 mm (1.1417 in) Measure: • Valve spring tilt “a” Tilt limit: 2.0 mm (0.0787 in) Out of specifications ...

  • Page 71: Valve Lapping

    VALVES Measure: • Valve face contact width “a” Make sure that the contact width along the entire valve face is within specifications. Valve face contact width (Intake): 0.9–1.1 mm (0.0354–0.0433 in) Valve face contact width (Exhaust): 0.9–1.1 mm (0.0354–0.0433 in) Limit (Intake): 1.6 mm (0.063 in) Limit (Exhaust):...

  • Page 72: Installing The Valves And Valve Springs

    VALVES Once the contacting surface of the valve face is pol- ished and becomes shiny, apply mechanic’s blue lay- out fluid to make sure that there are traces of even contact in the center of the valve face. NOTICE Do not let the lapping compound enter the gap between the valve stem and the valve guide.

  • Page 73: Oil Pump

    OIL PUMP OIL PUMP 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 30 N ・ m (3.0 kgf ・ m, 22 lb ・ ft) 12 N ・ m (1.2 kgf ・ m, 8.7 lb ・ ft) 30 N ・...

  • Page 74: Disassembling The Oil Pump

    OIL PUMP DISASSEMBLING THE OIL PUMP Remove: • Crankcase cover 2 Remove: • Relief valve “1” Remove: • Oil pump cover “1” Remove: • Oil strainer cover “1” • Oil strainer “2” • Inner rotor “3” • Outer rotor “4” CHECKING THE OIL PUMP Check: •...

  • Page 75: Checking The Relief Valve

    OIL PUMP Measure: • Inner-rotor-to-outer-rotor-tip clearance “a” and “b” Out of specification  Replace the defective part(s). Inner-rotor-to-outer-rotor-tip clearance “a”: 0.0 mm (0.0 in) Inner-rotor-to-outer-rotor-tip clearance “b”: 0.19–0.35 mm (0.008–0.013 in) Check: • Oil pump operation Rough movement  Replace the defective part(s). CHECKING THE RELIEF VALVE Check: •...

  • Page 76: Assembling The Oil Pump

    OIL PUMP with the crankcase cover 2, apply LOCTITE®, and tighten to the specified torque. ASSEMBLING THE OIL PUMP Lubricate: • Inner rotor • Outer rotor Recommended lubricant: Engine oil Install: • Outer rotor “1” • Inner rotor “2” • Oil strainer “3” •...

  • Page 77: Installing The Crankcase Cover 2

    OIL PUMP INSTALLING THE CRANKCASE COVER 2 Clean: • Mating surfaces of the crankcase and the crank- case cover 2 (with a cloth dampened with lacquer thinner) Apply: • Sealant (onto the crankcase cover 2 mating surfaces) Three bond No.1217G® Install: •...

  • Page 78: Pistons, Camshaft, Crankcase, And Crankshaft

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT CRANKCASE 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 12 N ・ m (1.2 kgf ・ m, 8.7 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 7 N ・...
  • Page 79 PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 12 N ・ m (1.2 kgf ・ m, 8.7 lb ・ ft) 10 N ・ m (1.0 kgf ・ m, 7.2 lb ・ ft) 7 N ・...

  • Page 80: Pistons, Camshaft, And Crankshaft

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT PISTONS, CAMSHAFT, AND CRANKSHAFT 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) 20 N ・ m (2.0 kgf ・ m, 14 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Removing the pistons, camshaft, and Remove the parts in the order listed.

  • Page 81: Removing The Flyweight Shaft Assembly And Governor Fork

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT REMOVING THE FLYWEIGHT SHAFT ASSEMBLY AND GOVERNOR FORK Remove: • Crankcase cover 1 • Governor assembly Remove: • Clips “1” • Governor fork “2” • Washers “3” Remove: • Flyweight shaft assembly “1” • Washer “2” Remove the flyweight shaft assembly by tapping the weight shaft from outside of the crankcase cover 1.

  • Page 82: Assembling The Flyweight Shaft Assembly

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Check: • Weight • Flyweight shaft • Collar • Washer • Weight shaft Wear/damage  Replace. ASSEMBLING THE FLYWEIGHT SHAFT ASSEMBLY Install: • Weight shaft “1” • Circlip “2” • Washer “3” • Collar “4” •...

  • Page 83: Removing The Camshaft And Valve Lifters

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT (Refer to “INSTALLING THE THROTTLE BODY ASSEMBLY” on page 4-7) REMOVING THE CAMSHAFT AND VALVE LIFTERS The following procedure applies to all of the camshaft and valve lifters. Remove: • Camshaft “1” Remove the camshaft when the camshaft gear mark “a” and the crankshaft gear mark “b”...

  • Page 84: Checking The Valve Lifters

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Check: • Camshaft lobe dimensions “a” and “b” Camshaft lobe dimensions Lobe height “a” (Intake): 32.885 mm (1.2947 in) Limit: 32.785 mm (1.2907 in) Lobe height “a” (Exhaust): 33.957 mm (1.3369 in) Limit: 33.857 mm (1.3330 in) Base circle diameter “b”...

  • Page 85: Checking The Reed Valve

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Check: • Valve lifter Damage  Replace. CHECKING THE REED VALVE Check: • Reed valve Damage  Replace. INSTALLING THE VALVE LIFTERS AND CAMSHAFT The following procedure applies to all of the camshaft and valve lifters. Install: •...

  • Page 86: Installing The Cover 2

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Apply: • Sealant (onto the crankcase mating surfaces) Three bond No.1217G® Install: • Cover 1 • Cover 1 bolts “1” to “5” Tighten the bolts to the specified torque in order from “1” to “5”. Cover 1 bolt: 9 N·m (0.9 kgf·m, 6.5 lb·ft) INSTALLING THE COVER 2...

  • Page 87: Installing The Crankcase Cover 1

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT INSTALLING THE CRANKCASE COVER 1 Install: • Crankcase cover 1 • Crankcase cover 1 bolts “1” to “8” Tighten the bolts to the specified torque in two steps and in order from “1” to “8”. Crankcase cover 1 bolt: 1st: 12 N·m (1.2 kgf·m, 8.7 lb·ft) 2nd: 30 N·m (3.0 kgf·m, 22 lb·ft)
  • Page 88 PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Measure cylinder bore “C” by taking side-to-side and front- to-back measurements of the cylinder. Bore: 80.000–80.020 mm (3.1496–3.1504 in) Warpage limit: 80.025 mm (3.1506 in) “C” = maximum of D b. If out of specification, replace the crankcase assembly, and replace the piston and piston rings as a set.

  • Page 89: Checking The Crankcase

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT CHECKING THE CRANKCASE Check: • Crankcase Damage  Replace. • Bearing Noise/wear/rotational failure  Replace. CHECKING THE PISTON PINS The following procedure applies to all of the piston pins. Check: • Piston pin Blue discoloration/grooves  Replace the piston pin and then check the lubrication system.
  • Page 90 PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Measure: • Piston ring side clearance Out of specification  Replace the piston and pis- ton rings as a set. Before measuring the piston ring side clearance, eliminate any carbon deposits from the piston ring grooves and pis- ton rings.

  • Page 91: Checking The Crankshaft

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Top ring End gap (installed): 0.20–0.35 mm (0.0079–0.0138 in) Limit: 0.60 mm (0.0236 in) 2nd ring End gap (installed): 0.20–0.35 mm (0.0079–0.0138 in) Limit: 0.60 mm (0.0236 in) Oil ring End gap (installed): 0.20–0.70 mm (0.0079–0.0276 in) CHECKING THE CRANKSHAFT Check: •...

  • Page 92: Checking The Connecting Rods Oil Clearance

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT CHECKING THE CONNECTING RODS OIL CLEARANCE The following procedure applies to all of the connecting rods. Measure the oil clearance if replacing the crankshaft or connecting rod. Place a piece of Plastigauge® “1” on the crank pin horizontally.
  • Page 93 PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT rings and related components. Install: • Top ring “1” • 2nd ring “2” • Oil ring “3” • Be sure to install the top ring so that the “R” mark “a” faces toward the piston head. •...

  • Page 94: Installing The Crankshaft

    PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT INSTALLING THE CRANKSHAFT Make sure that the end gap of each piston ring is 90˚ positioned correctly, as shown in the illustration. 45˚ a. Top ring, oil ring expander b. Lower oil ring rail 90˚ c.
  • Page 95 • Piston #2 with the connecting rod #2 “1” position. • Make sure that the “ ” mark “a” on the piston #2 head faces toward the flywheel. • Make sure that the “YAMAHA” mark “b” on the connect- ing rod #2 faces toward the crankcase cover 1. Install: •...
  • Page 96 PISTONS, CAMSHAFT, CRANKCASE, AND CRANKSHAFT Install: • Connecting rod cap #2 “1” • Connecting rod cap #2 bolts “2” Connecting rod cap bolt: 20 N·m (2.0 kgf·m, 14 lb·ft) • Make sure that the “ ” mark “a” on the connecting rod #2 is aligned with the “...

  • Page 97: Fuel

    FUEL FUEL PUMPS 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 9 N ・ m (0.9 kgf ・ m, 6.5 lb ・ ft) 9 N ・ m (0.9 kgf ・ m, 6.5 lb ・ ft) Order Job/Parts to remove Q’ty Remarks...

  • Page 98: Removing The High-Pressure Fuel Pump

    FUEL PUMPS REMOVING THE HIGH-PRESSURE FUEL PUMP WARNING Cover fuel injector pipe 1 connections with a cloth when disconnecting them. Residual pressure in the fuel lines could cause fuel to spurt out when removing the fuel injector pipe 1. Disconnect: •...

  • Page 99: Checking The Low-Pressure Fuel Pump

    FUEL PUMPS CHECKING THE LOW-PRESSURE FUEL PUMP Check: • Fuel hose “1” • Fuel delivery hose “2” • Pulsar hose “3” • Low-pressure fuel pump “4” Cracks/damage  Replace. Check: • Low-pressure fuel pump operation ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Connect the manual vacuum pump (Pressure/vac- uum tester) “1”...

  • Page 100: Installing The High-Pressure Fuel Pump

    FUEL PUMPS NOTICE Be sure to disconnect the fuel injector pipe 1 by hand. Do not forcefully disconnect the hose with tools. b. Connect the Fuel pressure gauge “2” and fuel pres- sure adapter “3” to the fuel injector pipe 1. Fuel pressure gauge: YU-03153 Fuel pressure adapter:...
  • Page 101 FUEL PUMPS sure fuel pump joint until a distinct “click” is heard.

  • Page 102: Throttle Body Assembly

    THROTTLE BODY ASSEMBLY THROTTLE BODY ASSEMBLY 1.1 N ・ m (0.11 kgf ・ m, 0.80 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 8 N ・ m (0.8 kgf ・ m, 5.8 lb ・ ft) Order Job/Parts to remove Q’ty...

  • Page 103: Removing The Throttle Body Assembly

    THROTTLE BODY ASSEMBLY REMOVING THE THROTTLE BODY ASSEMBLY Remove: • Governor spring • Governor assembly • Throttle lever comp • Link rod/spring Remove: • Stay “1” • Breather hose “2” • Joint 1 “3” • Throttle body assembly “4” • Gaskets “5” CHECKING THE THROTTLE BODY ASSEMBLY Check: •...
  • Page 104 THROTTLE BODY ASSEMBLY Install: • Link rod/spring • Throttle lever comp • Governor assembly • Governor spring “1” • Install the bending portion (short) “a” of the governor spring “1” into the hole “c” of the throttle lever comp while installing the bending portion (long) “b”...

  • Page 105: Fuel Injectors And Intake Manifold

    FUEL INJECTORS AND INTAKE MANIFOLD FUEL INJECTORS AND INTAKE MANIFOLD 3.0 N ・ m (0.30 kgf ・ m, 2.2 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 9 N ・...
  • Page 106 FUEL INJECTORS AND INTAKE MANIFOLD 3.0 N ・ m (0.30 kgf ・ m, 2.2 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 7 N ・ m (0.7 kgf ・ m, 5.1 lb ・ ft) 9 N ・...

  • Page 107: Removing The Fuel Injectors

    FUEL INJECTORS AND INTAKE MANIFOLD REMOVING THE FUEL INJECTORS The following procedure applies to all of the fuel injectors and related components. Remove: • Air filter case (Refer to “AIR FILTER” on page 3-3) • ECU and rectifier/regulator (Refer to “ECU, RECTIFIER/REGULATOR, AND FUSES”...

  • Page 108: Installing The Fuel Injectors

    FUEL INJECTORS AND INTAKE MANIFOLD Remove: • Fuel injector Remove the fuel injector “1” with the inlet pipe “2” installed. Remove: • Inlet pipe After removing the retainer “1”, remove the inlet pipe “2” from the fuel injector. Check: • Fuel injectors Obstruction ...
  • Page 109 FUEL INJECTORS AND INTAKE MANIFOLD Install: • Retainer “1” Engage the claw “a” of the retainer with the projection “b” on the fuel injector, and install to the fuel injector. Install: • Fuel injector Engage the projection “a” on the fuel injector with the groove “b”...

  • Page 110: Removing The Manifold Absolute Pressure Sensor

    FUEL INJECTORS AND INTAKE MANIFOLD • ECU and rectifier/regulator (Refer to “ECU, RECTIFIER/REGULATOR, AND FUSES” on page 3-8) • Air filter case (Refer to “AIR FILTER” on page 3-3) REMOVING THE MANIFOLD ABSOLUTE PRESSURE SENSOR Disconnect: • Manifold absolute pressure sensor lead coupler Slide the lock “a”...

  • Page 111: Checking The Intake Manifold

    FUEL INJECTORS AND INTAKE MANIFOLD Remove: • Intake manifold “1” • Intake manifold joints “2” • Gaskets “3” CHECKING THE INTAKE MANIFOLD Check: • Intake manifold • Intake manifold joints Cracks/damage  Replace. INSTALLING THE INTAKE MANIFOLD Install: • Gaskets “1” •...

  • Page 112: Electrical

    ELECTRICAL CIRCUIT DIAGRAM (Gy) Br/G...
  • Page 113 CIRCUIT DIAGRAM 1. ECU (Engine Control Unit) 14.Rollover switch 2. Stator coil assembly 15.FI diagnostic tool coupler 3. Rectifier/regulator 16.Engine temperature sensor 4. Fuse (30 A) 17.Manifold absolute pressure sensor 5. Fuse (10 A) 18.Throttle position sensor 6. Fuse (10 A) 19.O sensor 7.

  • Page 114: Fuel Injection System

    FUEL INJECTION SYSTEM FUEL INJECTION SYSTEM FI DIAG TOOL INSTRUCTIONS Purpose This FI Diagnostic Tool is to diagnose electronic fuel injection system used on Yamaha MX825V- EFI, MX800V-EFI and MX775V-EFI engines. Functions There are 5 Modes in this diag tool.
  • Page 115 FUEL INJECTION SYSTEM BUTTONs AND LEDs The “UP” button “1”/“DOWN” button “2” The “UP”/“DOWN” buttons are used to scroll each MODE. The “UP”/“DOWN” buttons are used to decide “YES” or “NO” to delete history error code in “CLEAR” mode. Reboot FI Diagnostic Tool to push “UP”/“DOWN” buttons simultaneously for more than 3 sec- onds.
  • Page 116 FUEL INJECTION SYSTEM Operation (BUTTONs and LEDs) WAITING... NO ERROR CODE COM ERROR NO ERROR CODE SELECT CURRENT DOWN SELECT NO ERROR MODE CURRENT DIAG HISTORY CLEAR PROPERTY 1. CONNECT 10.SELECT 2. CONNECTED 11.CURRENT 3. CHANGE MODE 12.SELECT 4. (EACH) MODE 13.CURRENT 5.
  • Page 117 FUEL INJECTION SYSTEM Details • “CURRENT” MODE Display when there is error CURRENT 01/02 P0122 1. Selected Mode 3. Total number of Error Code 2. Error Code 4. Current page number on display Display when there is no error CURRENT NO ERROR CODE 1.
  • Page 118 FUEL INJECTION SYSTEM DIAG 14.7 1. Selected Mode 3. Unit 2. Selected Diag Code 4. Sensor output • “HISTORY” MODE Display when there is error code in the past HISTORY 01/02 P0122 1. Selected Mode 3. Total number of Error Code 2.
  • Page 119 FUEL INJECTION SYSTEM • “CLEAR” MODE HISTORY CLEAN? HISTORY HISTORY DELETED CANCELED 1. Question: Delete? 4. CANCELED 2. “DOWN” button: NO 5. DELETED 3. “UP” button: YES • “PROPERTY” MODE This MODE is not needed for usual maintenance.

  • Page 120: Fuel Injection Diagram

    FUEL INJECTION SYSTEM FUEL INJECTION DIAGRAM 1. Fuel filter 8. O sensor 2. Fuel pump (low pressure) 9. Engine temperature sensor 3. Fuel pump (high pressure) 10.Crankshaft position sensor 4. Fuel injector 11.Throttle body 5. ECU (Engine Control Unit) 12.Manifold absolute pressure sensor 6.

  • Page 121: Error Code List

    FUEL INJECTION SYSTEM ERROR CODE LIST Error Code System or Component Detail P0107 Manifold Absolute Pressure Sensor (MAP) MAP Circuit Low Voltage or Open P0108 Manifold Absolute Pressure Sensor (MAP) MAP Circuit High Voltage P0112 Intake Air Temperature Sensor (IAT) IAT Circuit Low Voltage P0113 Intake Air Temperature Sensor (IAT)

  • Page 122: Diag Code List

    FUEL INJECTION SYSTEM DIAG CODE LIST DIAG Tool Diag What to dis- Item Unit How to diagnosis Mode Code play • Compare the sensor output value with atmospheric absolute pressure (Exam- Manifold Manifold ple: 14.7 psi) with engine stopped. Absolute Absolute •...

  • Page 123: Fuel Injection System Troubleshooting

    FUEL INJECTION SYSTEM FUEL INJECTION SYSTEM TROUBLESHOOTING Error Code No. P0107, P0108 Error Code P0107 System or Component Manifold Absolute Pressure Sensor (MAP) Detail of Error MAP Circuit Low Voltage or Open • Poor engine start Engine Symptoms • Poor driveability •...
  • Page 124 FUEL INJECTION SYSTEM Error Code No. P0112, P0113 Error Code P0112 System or Component Intake Air Temperature Sensor (IAT) Detail of Error IAT Circuit Low Voltage • Poor engine start • Poor driveability Engine Symptoms • Deteriorated exhaust • Unstable engine idling Engine Running availability Able to run engine DIAG Tool Code...
  • Page 125 FUEL INJECTION SYSTEM Error Code No. P0117, P0118 Error Code P0117 System or Component Engine Temperature Sensor (ET) Detail of Error Engine Temperature Sensor Circuit Low Voltage • Poor engine start • Poor driveability Engine Symptoms • Deteriorated exhaust • Unstable engine idling Engine Running availability Able to run engine DIAG Tool Code...
  • Page 126 FUEL INJECTION SYSTEM Error Code No. P0122, P0123 Error Code P0122 System or Component Throttle Position Sensor (TPS) Detail of Error TPS Circuit Low Voltage or Open • Poor engine start (There is possibility it can’t start) • Poor driveability Engine Symptoms •...
  • Page 127 FUEL INJECTION SYSTEM Error Code No. P0131, P0132 Error Code P0131 System or Component Oxygen Sensor Detail of Error Circuit Low Voltage Engine Symptoms Deteriorated exhaust Engine Running availability Able to run engine Mode “DIAG”, Code “O ” DIAG Tool Code Diagnosing —...
  • Page 128 FUEL INJECTION SYSTEM Error Code No. P0032, P0031 Error Code P0032 System or Component Oxygen Sensor Heater Detail of Error Heater Circuit High Voltage Engine Symptoms Deteriorated exhaust (until exhaust gas heated after engine starts) Engine Running availability Able to run engine DIAG Tool Code —...
  • Page 129 FUEL INJECTION SYSTEM Error Code No. P0201, P0202 Error Code P0201 System or Component Fuel Injector Detail of Error Injector #1 Circuit Malfunction Engine Symptoms Cylinder #1 stops Engine Running availability Able to run with Cylinder #2 alone DIAG Tool Code —...
  • Page 130 FUEL INJECTION SYSTEM Error Code No. P0230, P0232 Error Code P0230 System or Component Fuel Pump Relay (FPR) Detail of Error FPR Coil Circuit Low Voltage or Open • Engine stop Engine Symptoms • Unable to start engine Engine Running availability Unable to run engine DIAG Tool Code —...
  • Page 131 FUEL INJECTION SYSTEM Error Code No. P0336, P0337 Error Code P0336 System or Component Crankshaft Position Sensor (CPS) Detail of Error CPS Sensor Noisy Signal • Poor engine start (There is possibility it can’t start) • Poor driveability Engine Symptoms •...
  • Page 132 FUEL INJECTION SYSTEM Error Code No. P0351, P0352 Error Code P0351 System or Component Ignition Coil Detail of Error Cylinder #1 Ignition Coil Malfunction Engine Symptoms Cylinder #1 stops operating (Injector also stops operating.) Engine Running availability Able to run with Cylinder #2 alone DIAG Tool Code —...
  • Page 133 FUEL INJECTION SYSTEM Error Code No. P0562, P0563 Error Code P0562 System or Component System Voltage Detail of Error System Voltage Low • Engine stop Engine Symptoms • Unable to start engine Engine Running availability Depends on the case DIAG Tool Code —...
  • Page 134 FUEL INJECTION SYSTEM Error Code No. P0171, P0172, P0174 Error Code P0171 System or Component BLM MaxAdapt Detail of Error Correction amount of injection fuel is beyond upper limit • Poor engine start (There is possibility it can’t start) • Poor driveability Engine Symptoms •...
  • Page 135 FUEL INJECTION SYSTEM Error Code P0174 System or Component PE system Lean Detail of Error Lean fuel ratio • Poor drivability • Deteriorated exhaust Engine Symptomes • Unstable engine idling (Different idling engine rpm) • Overheat • Engine knock sound Engine Running availability Able to run engine DIAG Tool Code...

  • Page 136: Electrical Components

    ELECTRICAL COMPONENTS ELECTRICAL COMPONENTS 5-25...
  • Page 137 ELECTRICAL COMPONENTS 1. Manifold absolute pressure sensor 2. Fuel injector 3. Engine temperature sensor 4. High-pressure fuel pump 5. Oil pressure switch 6. Ignition coil/spark plug cap 7. Stator coil assembly 8. Rectifier/regulator 9. Crankshaft position sensor 10.Throttle position sensor 11.O sensor 12.ECU (Engine Control Unit)

  • Page 138: Checking The Switch Continuity

    ELECTRICAL COMPONENTS CHECKING THE SWITCH CONTINUITY Check each switch for continuity with the tester. If the con- tinuity reading is incorrect, check the wiring connections O.L” and if necessary, replace the switch. NOTICE Never insert the tester probes into the coupler termi- Ω”...

  • Page 139: Checking The Oil Pressure Switch

    ELECTRICAL COMPONENTS Set the digital circuit tester selector to “”. Model 88 Multimeter with tachometer: YU-A1927 b. If the digital circuit tester indicates “O.L”, replace the fuse. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ Replace: • Blown fuse ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Set the main switch to “OFF”. b.

  • Page 140: Checking Manifold Absolute Pressure Sensor

    ELECTRICAL COMPONENTS Connect: • Digital circuit tester (between the engine ground and oil pressure switch terminal) Model 88 Multimeter with tachometer: YU-A1927 Check: • Oil pressure switch continuity No continuity  Replace the oil pressure switch. CHECKING MANIFOLD ABSOLUTE PRESSURE SENSOR Connect: •...

  • Page 141: Checking The Crankshaft Position Sensor

    ELECTRICAL COMPONENTS Resistance: 3.0–7.0 k ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Connect the digital circuit tester () to the throttle position sensor terminals as shown. Model 88 Multimeter with tachometer: YU-A1927 • Positive tester probe  Terminal “a” • Negative tester probe  Terminal “b” b.

  • Page 142: Checking The Engine Temperature Sensor

    ELECTRICAL COMPONENTS • Positive tester probe  White/Red “1” (wire harness color) • Negative tester probe  Black “2” (wire harness color) b. Measure the crankshaft position sensor resistance. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ CHECKING THE ENGINE TEMPERATURE SENSOR Remove: • Engine temperature sensor WARNING •...

  • Page 143: Checking The Ignition Coils

    ELECTRICAL COMPONENTS e. Measure the engine temperature sensor resis- tance. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ Install: • Engine temperature sensor CHECKING THE IGNITION COILS The following procedure applies to all of the ignition coils. Check: • Primary coil resistance Out of specification  Replace. Primary coil resistance: 0.44–0.66 ...

  • Page 144: Checking The Ignition Spark Gap

    ELECTRICAL COMPONENTS • Positive tester probe  Red “1” (wire harness color) • Negative tester probe  High-tension cord “2” b. Measure the secondary coil resistance. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ CHECKING THE IGNITION SPARK GAP The following procedure applies to all of the ignition coils. Check: •...

  • Page 145: Checking The Stator Coil Assembly

    ELECTRICAL COMPONENTS ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Remove the spark plug cap from the high tension cord. b. Connect the digital circuit tester () to the spark plug cap as shown. Model 88 Multimeter with tachometer: YU-A1927 • Positive tester probe  Spark plug side “1” •...

  • Page 146: Checking The Rectifier/Regulator

    ELECTRICAL COMPONENTS CHECKING THE RECTIFIER/REGULATOR Check: • Rectifier/regulator output voltage Out of specification  Replace the rectifier/regula- tor. Regulated voltage: 14–15 V ▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼ a. Connect FI Diagnostic Tool. b. Connect the digital circuit tester (DC) to the rectifier/ regulator harness. FI Diagnostic Tool: 90890-03253 Model 88 Multimeter with tachometer:...

  • Page 147: Checking The Starter Motor Operation

    ELECTRICAL COMPONENTS Model 88 Multimeter with tachometer: YU-A1927 • Positive tester probe  Injector terminal “1” • Negative tester probe  Injector terminal “2” c. Measure the fuel injector resistance. ▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ CHECKING THE STARTER MOTOR OPERATION Check: • Starter motor operation Does not operate ...

  • Page 148: Electric Starting System

    ELECTRIC STARTING SYSTEM ELECTRIC STARTING SYSTEM REMOVING THE STARTER MOTOR 9 N ・ m (0.9 kgf ・ m, 6.5 lb ・ ft) 23 N ・ m (2.3 kgf ・ m, 17 lb ・ ft) Order Job/Parts to remove Q’ty Remarks Removing the starter motor Remove the parts in the order listed.

  • Page 149: Disassembling The Starter Motor

    ELECTRIC STARTING SYSTEM DISASSEMBLING THE STARTER MOTOR 6 N ・ m (0.6 kgf ・ m, 4.3 lb ・ ft) 9 N ・ m (0.9 kgf ・ m, 6.5 lb ・ ft) 11 N ・ m (1.1 kgf ・ m, 8.0 lb ・ ft) Order Job/Parts to remove Q’ty...

  • Page 150: Checking The Armature Coil

    ELECTRIC STARTING SYSTEM CHECKING THE ARMATURE COIL Check: • Commutator (outer surface) Dirty  Clean it with #600 grit sandpaper. Measure: • Mica (insulation depth between the commutator segments) Out of specification  Scrape the mica to the proper measurement using a hacksaw blade which has been grounded to fit the commutator.

  • Page 151: Checking The Brush

    ELECTRIC STARTING SYSTEM CHECKING THE BRUSH Measure: • Brush length (of each brush) “1” Out of specification  Replace. Brush wear limit length: 6.0 mm (0.2362 in) Check: • Brush spring “2” Fatigue/damage  Replace. CHECKING THE STARTER RELAY Measure: •...
  • Page 152 ELECTRIC STARTING SYSTEM Install: • Armature and starter drive lever “1” Install: • Starter relay “1” Starter relay nut: 11 N·m (1.1 kgf·m, 8.0 lb·ft) 5-41...

  • Page 153: Troubleshooting

    TROUBLESHOOTING ENGINE DOES NOT START IGNITION SYSTEM The ignition system fails to operate (no spark or intermittent spark). Checking steps Possible remedy Check the fuses. Replace the fuse(s). (Refer to “CHECKING THE FUSES” on page 5-27) • Clean the battery terminals. Check the battery.

  • Page 154: Electric Starting System

    ENGINE DOES NOT START ELECTRIC STARTING SYSTEM The starter motor fails to turn. Checking steps Possible remedy Check the fuses. Replace the fuse(s). (Refer to “CHECKING THE FUSES” on page 5-27) • Clean the battery terminals. Check the battery. • Recharge or replace the battery. Check the starter motor operation.

  • Page 155: Other Troubles

    OTHER TROUBLES OTHER TROUBLES ENGINE STARTS BUT STALLS Checking steps Possible remedy Check the fuel level. Add the fuel if it is insufficient. Check if the fuel filter is clogged. Clean or replace. Check if the fuel hoses is clogged. Clean.

  • Page 156: Engine Speed Does Not Increase

    OTHER TROUBLES ENGINE SPEED DOES NOT INCREASE Checking steps Possible remedy Check the spark plugs for dirt and check the spark plug Clean, adjust, or replace the spark gap. plugs. Check the air filter element for dirt. Replace the air filter element. Clean or replace spark arrester, muffler Check spark arrester, muffler and air filter.

  • Page 157: Engine Speed Is Uneven

    OTHER TROUBLES ENGINE SPEED IS UNEVEN Checking steps Possible remedy Check the fuel level. Add the fuel if it is insufficient. Check if fuel has deteriorated. Replace the fuel. Check the spark plugs for dirt and check the spark plug Clean, adjust, or replace the spark gap.

  • Page 158: Governor Operation

    OIL PRESSURE SYSTEM GOVERNOR OPERATION Checking steps Possible remedy Check that the governor link operate smoothly. Adjust or replace. Check that the governor spring is stretched. Replace. Check the governor adjustment. (Refer to “INSTALLING THE THROTTLE BODY ASSEM- Adjust. BLY” on page 4-7) Check the governor weight and governor bushing function.

  • Page 159: Specifications

    SPECIFICATIONS GENERAL SPECIFICATIONS Model: MX775 (7U2J) MX800 (7U1J) MX825 (7UDJ) Dimensions: Overall length 499 mm (19.65 in) Overall width 463 mm (18.23 in) Overall height 639 mm (25.16 in) Dry weight 60 kg (132 lb) Engine: Engine type Air cooled 4-stroke gasoline OHV...
  • Page 160 GENERAL SPECIFICATIONS * Yamaha engine has been designed to use regular unleaded gasoline with a pump octane number ***** ((R+M)/2) of 86 or higher, or research octane number of 91 or higher. Gasohol containing ethanol can be used if the ethanol content does not exceed 10 % (E10).

  • Page 161: Maintenance Specifications

    MAINTENANCE SPECIFICATIONS MAINTENANCE SPECIFICATIONS ENGINE Piston: Piston-to-cylinder clearance 0.033–0.047 mm (0.0013–0.0019 in) Limit 0.15 mm (0.0059 in) Piston diameter 79.959–79.980 mm (3.1480–3.1488 in) Limit 79.900 mm (3.1457 in) Measuring point (from piston 6.0 mm (0.2362 in) skirt bottom) Oversize 1st 80.25 mm (3.1594 in) 80.50 mm (3.1693 in) Piston pin hole inside diameter...
  • Page 162 MAINTENANCE SPECIFICATIONS Crankshaft: Big end side clearance 0.20–0.65 mm (0.0079–0.0256 in) Runout limit 0.03 mm (0.0012 in) Crank pin outside diameter 40.950–41.050 mm (1.6122–1.6161 in) Connecting rod: Small end diameter 19.006–19.020 mm (0.7483–0.7488 in) Oil clearance 0.006–0.025 mm (0.0002–0.0010 in) Big end diameter 40.005–40.020 mm (1.5750–1.5756 in) Oil clearance...
  • Page 163 MAINTENANCE SPECIFICATIONS Limit (Intake) 1.6 mm (0.063 in) Limit (Exhaust) 1.6 mm (0.063 in) Valve stem runout limit 0.01 mm (0.0004 in) Valve guide Guide inside diameter (Intake) 6.000–6.012 mm (0.2362–0.2367 in) Guide inside diameter (Exhaust) 6.000–6.012 mm (0.2362–0.2367 in) Stem to guide clearance (Intake) 0.08 mm (0.0031 in) Stem to guide clearance...
  • Page 164 Oil pump: Inner-rotor-to-outer-rotor-tip 0.19–0.35 mm (0.008–0.013 in) clearance Relief valve operating pressure 342–538 kPa (3.42–5.38 kgf/cm², 49.59–78.01 psi) Throttle body: ID mark E-3750-2 (MX775) E-3750-1 (MX800) E-3750-0 (MX825) Throttle position sensor: Output voltage (at idle) 0.95–4.5 V Resistance 3.0–7.0 k...

  • Page 165: Electrical

    MAINTENANCE SPECIFICATIONS ELECTRICAL Ignition coil: 0.44–0.66  Primary coil resistance Secondary coil resistance 5.6–8.4 k Spark plug cap resistance 3.75–6.25 k Crankshaft position sensor air 0.5–1.5 mm (0.02–0.06 in) Minimum ignition spark gap 6.0 mm (0.236 in) Charging system: Standard output at 3600 r/min 18 A: More than 18 A 20 A: More than 20 A 25 A: More than 25 A...
  • Page 166 TIGHTENING TORQUES TIGHTENING TORQUES Item Thread size Tightening torque M14S  1.25 Spark plug 20 N·m (2.0 kgf·m, 14 lb·ft) Spark arrester screw — 3.5 N·m (0.35 kgf·m, 2.5 lb·ft) Oil filter — 14 N·m (1.4 kgf·m, 10 lb·ft) M12  1.5 Oil drain bolt 27 N·m (2.7 kgf·m, 20 lb·ft) M6 ...
  • Page 167 TIGHTENING TORQUES Item Thread size Tightening torque M10  1.5 Engine temperature sensor 12 N·m (1.2 kgf·m, 8.7 lb·ft) M6  1.0 Reed valve 10 N·m (1.0 kgf·m, 7.2 lb·ft) M6  1.0 Scroll air shroud bolt 7 N·m (0.7 kgf·m, 5.1 lb·ft) M6 ...

  • Page 168: Tightening Torques

    GENERAL TORQUE SPECIFICATIONS GENERAL TORQUE SPECIFICATIONS This chart specifies torque for standard fasteners with standard I.S.O. pitch threads. Torque specifi- cations for special components or assemblies are included in the applicable sections of this book. To avoid warpage, tighten multi fastener assemblies in a crisscross fashion, in progressive stages, until full torque is reached.

  • Page 169: Lubrication Points And Type Of Lubricants

    LUBRICATION POINTS AND TYPE OF LUBRICANTS LUBRICATION POINTS AND TYPE OF LUBRICANTS Part name Type of lubricant Oil seal lip Oil hose 1, 2 Governor fork oil seal lip Bearing Connecting rod big end Crank pin Crankshaft journal Connecting rod cap bolt Piston pin Piston Valve stem...

  • Page 170: Wire Routing Diagram

    WIRE ROUTING DIAGRAM WIRE ROUTING DIAGRAM UPPER SIDE VIEW 7-12...
  • Page 171 WIRE ROUTING DIAGRAM 1. Hose clamp 8. Wire harness 2. Inlet pipe 2 9. Purge hose 2 3. Fuel injector #2 10.3 WAY joint 4. Fuel injector pipe 2 11.Purge hose 1 5. Fuel injector #1 12.Plastic locking tie 6. Inlet pipe 1 13.Fuel injector pipe 1 7.
  • Page 172 WIRE ROUTING DIAGRAM 7-14...
  • Page 173 WIRE ROUTING DIAGRAM 1. Crankshaft position sensor 12.Fuel injector #2 coupler 2. Ignition coil #2 13.Manifold absolute pressure sensor lead 3. Throttle position sensor lead 14.Ignition coil #2 coupler 4. Engine temperature sensor lead 15.Fuel injector #1 lead 5. O sensor lead 16.Ignition coil #1 lead 6.

  • Page 174: Left Side View

    WIRE ROUTING DIAGRAM LEFT SIDE VIEW 7-16...
  • Page 175 WIRE ROUTING DIAGRAM 1. Rectifier/regulator 15.Fuse (10 A) coupler 2. Earth terminal 16.Fuse (30 A) coupler 3. ECU 17.Starter motor 4. ECU coupler (black) 18.Plastic locking tie 5. ECU coupler (gray) 19.Throttle body 6. Fuel injector #1 lead 20.Throttle position sensor lead 7.

  • Page 176: Right Side View

    WIRE ROUTING DIAGRAM RIGHT SIDE VIEW 7-18...
  • Page 177 WIRE ROUTING DIAGRAM 1. Hose clamp 7. Fuel filter 2. Low-pressure fuel pump 8. Plastic locking tie 3. Fuel delivery hose 9. Lead 1 4. Fuel injector pipe 1 10.Purge hose 1 5. Fuel hose 11.Pulsar hose 6. High-pressure fuel pump A.
  • Page 178 WIRE ROUTING DIAGRAM 1. Oil hose 1 4. Oil hose 2 2. Oil cooler 5. Oil filter 3. Hose clamp A. Insert the oil hose all the way into the oil cooler. B. Face the projection inward. C. Install the white painted portion in the direction shown in the illustration. D.
  • Page 179 WIRE ROUTING DIAGRAM 1. Fuel injector #2 lead 5. High-pressure fuel pump coupler 2. Ignition coil #2 lead 6. Oil pressure switch 3. High-pressure fuel pump lead 7. Oil pressure switch lead 4. Purge hose 8. Spark plug cap A. The high-pressure fuel pump coupler should be laid along the purge hose. B.

  • Page 180: Rear Side View

    WIRE ROUTING DIAGRAM REAR SIDE VIEW 7-22...
  • Page 181 WIRE ROUTING DIAGRAM 1. Air filter cover 1 4. Joint 2 2. Air filter case stay 5. Air filter case 3. Breather hose A. Install the air filter case stay into the groove in the air filter case. B. Install the screw in the direction shown in the illustration. C.
  • Page 182 WIRE ROUTING DIAGRAM 1. Manifold absolute pressure sensor coupler 5. Plastic locking tie 2. Manifold absolute pressure sensor 6. Inlet manifold 3. Clamp 7. Ignition coil #1 lead 4. O sensor coupler 8. Fuel injector #1 lead A. FI diagnostic tool coupler B.
  • Page 183 WIRE ROUTING DIAGRAM MEMO 7-25...
  • Page 184 APPENDIX CIRCUIT DIAGRAM (Gy)
  • Page 185 1. ECU (Engine Control Unit) 14.Rollover switch 2. Stator coil assembly 15.FI diagnostic tool coupler 3. Rectifier/regulator 16.Engine temperature sensor 4. Fuse (30 A) 17.Manifold absolute pressure sensor 5. Fuse (10 A) 18.Throttle position sensor 6. Fuse (10 A) 19.O sensor 7.
  • Page 186 MEMO...
  • Page 188 2016.12×1 !

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