EB000000 YP250 SERVICE MANUAL ©1996 by Yamaha Motor Co., Ltd. 1st Edition, January 1996 All rights reserved. Any reprinting or unauthorized use without the written permission of Yamaha Motor Co., Ltd. is expressly prohibited. EB001000 NOTICE This manual was produced by the Yamaha Motor Company 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, so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha scooter has a basic understanding of the mechanical ideas and the procedures of scooter repair. Repairs attempted by anyone without this knowledge are likely to render the scooter unsafe and unfit for use. Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications and significant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and will appear in future editions of this manual where applicable. NOTE: Designs and specifications are subject to change without notice. IMPORTANT INFORMATION Particularly important information is distinguished in this manual by the following notations. The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED! Failure to follow WARNING instructions could result in severe injury or death to the scooter operator, a bystander or a person inspecting or repairing the scooter. CAUTION: NOTE: A CAUTION indicates special precautions that must be taken to avoid damage to the scooter. A NOTE provides key information to make procedures easier or clearer. YP002000 HOW TO USE THIS MANUAL MANUAL ORGANIZATION This manual consists of chapters for the main categories of subjects. (See "Illustrated symbols") 1st title 1 : 2nd title 2 : 3rd title 3 : This is the title of the chapter with its symbol on the upper right corner of each page. This title indicates the section of the chapter and only appears on the first page of each section. It is located in the upper left corner of the page. This title indicates a sub-section that is followed by step-by-step procedures accompanied by corresponding illustrations. EXPLODED DIAGRAMS To heps identify parts and clarify procedure steps, there are exploded diagrams at start of each removal and disassembly section. 1. An easy-to-see exploded diagram 4 is provided for disassembly and assembly jobs. 2. Numbers 5 are given in the order of jobs in the exploded diagram. A number that is enclosed by a circle indicates a disassembly step. 3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol marks 6 . The meanings of the symbol marks are given on the next page. 4. A job instruction chart 7 accompanies the exploded diagram, providing the order of jobs, names of parts, notes in jobs, etc. 5. For jobs requiring more information, the step-by-step format supplements 8 are given in addition to the exploded diagram and the job instruction chart. 2 1 4 3 5 8 6 6 7 EB003000 1 2 ILLUSTRATED SYMBOLS Illustrated symbols 1 to 9 are designed as thumb tabs to indicate the chapter's number and content. 1 2 3 4 5 6 7 8 9 General information Specifications Periodic inspection and adjustment Engine Cooling system Carburetion Chassis Electrical Troubleshooting 3 4 5 6 7 8 9 10 Illustrated symbols 10 to 17 are used to identify the specifications appearing in the text. 10 11 12 13 14 15 16 17 11 12 13 14 Possible to maintain with engine mounted Filling fluid Lubricant Special tool Tightening Wear limit, clearance Engine speed , V, A 15 16 17 Illustrated symbols 18 to 23 in the exploded diagrams indicate the types of lubricants and lubrication points. 18 19 20 18 19 20 21 22 23 21 22 23 Apply engine oil Apply gear oil Apply molybdenum disulfide oil Apply wheel bearing grease Apply lightweight lithium-soap base grease Apply molybdenum disulfide grease Illustrated symbols 24 to 25 in the exploded diagrams indicate the where to apply locking agent 24 and when to install new parts 25 . 24 25 24 Apply locking agent (LOCTITE®) 25 Use new one INDEX GENERAL INFORMATION SPECIFICATIONS PERIODIC INSPECTION AND ADJUSTMENT ENGINE OVERHAUL COOLING SYSTEM CARBURETION CHASSIS ELECTRICAL TROUBLESHOOTING GEN INFO 1 2 3 4 5 6 7 8 9 SPEC INSP ADJ ENG COOL CARB CHAS ELEC TRBL SHTG CHAPTER 1 GENERAL INFORMATION SCOOTER IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VEHICLE IDENTIFICATION NUMBER (for E) . . . . . . . . . . . . . . . . . . . FRAME SERIAL NUMBER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ENGINE SERIAL NUMBER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MODEL LABEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OIL INDICATOR LIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AUTO CHOKE SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IGNITION CIRCUIT CUT-OFF SYSTEM . . . . . . . . . . . . . . . . . . . . . . . IMPORTANT INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PREPARATION FOR REMOVAL PROCEDURES . . . . . . . . . . . . . . . REPLACEMENT PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GASKETS, OIL SEALS, AND O-RINGS . . . . . . . . . . . . . . . . . . . . . . . . LOCK WASHERS/PLATES AND COTTER PINS . . . . . . . . . . . . . . . . BEARINGS AND OIL SEALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CIRCLIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHECKING OF CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HOW TO USE THE CONVERSION TABLE . . . . . . . . . . . . . . . . . . . . . SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1-1 1-1 1-1 1-1 1-2 1-2 1-3 1-3 1-4 1-4 1-4 1-4 1-5 1-5 1-5 1-6 1-7 1-8 SCOOTER IDENTIFICATION YP100000 GEN INFO GENERAL INFORMATION SCOOTER IDENTIFICATION YP100010 VEHICLE IDENTIFICATION NUMBER (for E) The vehicle identification number 1 is stamped into the right side of the frame. NOTE: The vehicle identification number is used to identify your scooter and may be used to register your scooter with the licensing authority in your country. YP100020 FRAME SERIAL NUMBER (except for E) The frame serial number 1 is stamped into the right side of the frame. EB100030 ENGINE SERIAL NUMBER The engine serial number 1 is stamped into the crankcase. NOTE: Designs and specifications are subject to change without notice. MODEL LABEL The model label 1 is affixed under the seat. This information will be needed to order spare parts. 1-1 FEATURES GEN INFO FEATURES OIL INDICATOR LIGHT S Function Pulses (travel distance signals) from the speedometer are counted and cause the oil indicator light to come on at 1,000 km for the first time and thereafter every 3,000 km. In this way, this light indicates the time for oil change. S Circuit diagram Main switch Oil indicator light Reset button Fuse Battery Meter C.P.U Oil indicator light Reset button Engine stop Ignitor unit switch S Resetting procedure Travel distance can be reset if the reset button is held down for 2 to 5 seconds with the main switch "ON". 1) If the "resetting" is done while the oil light is on, the oil indicator light goes off for resetting confirmation. 2) If the "resetting" is done while the oil light is off, the oil indicator light comes on for 1.4 seconds for resetting confirmation. S Failure diagnosis 1) Checking oil indicator light for breakage This oil indicator light is kept on for 1.4 seconds immediately after the main switch is turned on, thereby checking the bulb for breakage. 2) In case of meter pulse failure If travel distance signals are not detected during running, the oil indicator light flashes and gives a warning of meter signal failure. NOTE: This circuit may be activated if the engine is accelerated without load with the mainestand put up. S Battery tending to discharge. If the starting motor is run with the battery tending to discharge, the oil indicator light may come on (for 1.4 seconds), but this is noting abnormal. In this case recharge or replace battery. This light comes on if battery charging becomes poor, thereby causing the engine to run as low as about 200 rpm against 600 rpm or so, 1-2 FEATURES GEN INFO AUTO-CHOKE SYSTEM This system is the parallel connection of the ignitor unit circuit and the thermo switch as shown, detecting the engine temperature, and facilitates the restarting with the warm engine. S Circuit diagram Igniter unit Main switch Fuse Battery Thermo switch Ignition C.P.U Auto-choke S Auto-choke operation Engine condition Thermo switch Ignitor unit circuit Auto-choke Start with the cold engine OFF OFF Activates Crank with the cold engine OFF ON Activates Crank with the warm engine ON ON Not activate Restart with the warm engine ON OFF Not activate IGNITION CIRCUIT CUT-OFF SYSTEM A sidestand circuit is added to the existing electric starting circuit, thereby controlling the starter motor operation and the ignition system of the igniter unit. S Circuit diagram Main switch Engine stop switch Brake switch Fuse Starter relay Relay Ignitor unit Battery Starter motor Start switch Brake light Sidestand switch S Operating mode Sidestand switch OFF (Sidestand in use) ON (Sidestand folded in) Operation of brake light ON OFF ON OFF Operation of starter motor Not operated Not operated Operated Not operated Operation of igniter unit control Misfire Misfire Ignited Ignited (ridden) 1-3 IMPORTANT INFORMATION EB101000 GEN INFO IMPORTANT INFORMATION PREPARATION FOR REMOVAL PROCEDURES 1. Remove all dirt, mud, dust and foreign material before removal and disassembly. 2. Use proper tools and cleaning equipment. 3. Refer to the "SPECIAL TOOLS" section. 4. When disassembling the machine, always keep mated parts together. This includes gears, cylinders, pistons and other parts that have been "mated" through normal wear. Mated parts must always be reused or replaced as an assembly. 5. During machine disassembly, clean all parts and place them in trays in the order of disassembly. This will speed up assembly and allow for the correct installation of all parts. 6. Keep all parts away from any source of fire. EB101010 REPLACEMENT PARTS 1. Use only genuine Yamaha parts for all replacements. Use oil and grease recommended by Yamaha for all lubrication jobs. Other brands may be similar in function and appearance, but inferior in quality. EB101020 GASKETS, OIL SEALS AND O-RINGS 1. Replace all gaskets, seals and O-rings when overhauling the engine. All gasket surfaces, oil seal lips and O-rings must be cleaned. 2. Properly oil all mating parts and bearings during reassembly. Apply grease to the oil seal lips. 1-4 IMPORTANT INFORMATION EB101030 GEN INFO OR LOCK WASHERS/PLATES AND COTTER PINS 1. Replace all lock washers/plates and cotter pins after removal. Bend lock tabs along the bolt or nut flats after the bolt or nut has been tightened to specification. EB101040 BEARINGS AND OIL SEALS Install bearings and oil seals so that the manufacturer's marks or numbers are visible. When installing oil seals, apply a light coating of lightweight lithium base grease to the seal lips. Oil bearings liberally when installing, if appropriate. 1 Oil seal CAUTION: Do not use compressed air to spin the bearings dry. This will damage the bearing surfaces. 1 Bearing EB101050 CIRCLIPS 1. Check all circlips carefully before reassembly. Always replace piston pin clips after one use. Replace distorted circlips. When installing a circlip 1 , make sure that the sharp-edged corner 2 is positioned opposite the thrust 3 it receives. See sectional view. 4 Shaft 1-5 IMPORTANT INFORMATION EB801000 GEN INFO CHECKING OF CONNECTIONS Dealing with stains, rust, moisture, etc. on the connector. 1. Disconnect: S Connector 2. Dry each terminal with an air blower. 3. Connect and disconnect the connector two or three. 4. Pull the lead to check that it will not come off. 5. If the terminal comes off, bend up the pin 1 and reinsert the terminal into the connector. 6. Connect: S Connector NOTE: The two connectors "click" together. 7. Check for continuity with a tester. NOTE: D If there is no continuity, clean the terminals. D Be sure to perform the steps 1 to 7 listed above when checking the wireharness. D For a field remedy, use a contact revitalizer available on the market. D Use the tester on the connector as shown. 1-6 HOW TO USE THE CONVERSION TABLE EB201000 GEN INFO HOW TO USE THE CONVERSION TABLE All specification data in this manual are listed in SI and METRIC UNITS. Use this table to convert METRIC u ...