INDEX GENERAL INFORMATION PERIODIC INSPECTIONS AND ADJUSTMENTS ENGINE CARBURETION DRIVE TRAIN CHASSIS ELECTRICAL APPENDICES "- ENG .(D. DR IV iii ELEC ~, APPX
<D (j) 1fm!b1~1 I~I.I ® @ I ENG 1'-1 ~.I @ ® ~RBI f 1 I DRIV 1-1&-1 (j) ® FH~~I IE~ECI iii 1 @ @) ~ IAPPXI~'1 CO) ~ @ If] @ ~ ® § @ [mJ @ • @, @ • @~ ® ® @ _8 .... .--§l1 ~ ILLUSTRATED SYMBOLS (Refer to the illustration) Illustrated symbols CD to ® are designed as thumb tabs to indicate the chapter's number and content. <D General information <i) Periodic inspection and adjustment @ Engine ® Cooling system ® Carburetion ® Drive train (j) Chassis @ Electrical ® Appendices Illustrated symbols @ to @) are used to iden .. tify the specifications appearing. @ Filling fluid CO) Lubricant @Tightening @Wear limit, clearance ® Engine speed @n,V,A Illustrated symbols @ to @ in the exploded diagram indicate grade of lubricant and location of lubrication point. @ Apply locking agent (LOCTITE® ) @ Apply engine oil @ Apply gear oil @ Apply molybdenum disulfide oil ® Apply wheel bearing grease ® Apply lightweight lithium-soap base grease @ Apply molybdenum disulfide grease
CHAPTER 1. GENERAL INFORMATION MACHINE IDENTIFiCATION .................................... 1-1 VEHICLE IDENTIFICATION NUMBER ......................... 1-1 ENGINE SERIAL NUMBER .................................. 1-1 IMPORTANT INFORMATION .................................... 1-2 ALL REPLACEMENT PARTS ................................. 1-2 GASKETS, OIL SEALS, AND O-RINGS ........................ 1-2 LOCK WASHERS/PLATES AND COTTER PINS .................. 1-2 BEARINGS AND OIL SEALS ................................ 1-2 CI RCLIPS ................................................. 1-3 SPECIAL TOOLS .............................................. 1-3 FOR TUNE-UP ............................................. 1-3 FOR ENGINE SERViCE ..................................... 1-4 FOR MIDDLE GEAR SERViCE ............................... 1-7 FOR FINAL GEAR SERVICE .................................. 1-8 FOR DIFFERENTIAL GEAR SERVICE ......................... • 1-8 FOR CHASSIS SERVICE ....................... • ............. • 1-9 FOR ELECTRICAL COMPONENTS ............................. 1-9
I~l-'bl'-'I MACHINE IDENTIFICATION ,-, GENERAL INFORMATION MACHINE IDENTIFICATION VEHICLE IDENTIFICATION NUMBER The vehicle identification number CD is stamped into the left side of the frame. NOTE: ____________ _ The vehicle identification number is used to identify your machine and may be used to register you r mach ine with the licensing autho- rity in your state. Starting Serial Number: JV42HROO * HC000101 ENGINE SERIAL NUMBER The engine serial number CD is stamped into the right side of the engine. NOTE: __________________________ _ The first three digits of these numbers are for model identifications; the remaining digits are the unit production number. Starting Serial Number: 2HR-000101 " NOTE: ________________________ __ Designs and specifications are subject to change without notice.
IMPORTANT INFORMATION 1~1J=~lcfeal IMPORTANT INFORMATION 300-000 300-002 300-003 ALL REPLACEMENT PARTS 1. We recommended to use Yamaha genuine parts for all replacements. Use oil and/or grease recommended by Yamaha for as- sembly and adjustment. Other brands may be similar in function and appearance, but inferior in quality. \ GASKETS, Oil SEALS, AND O·RINGS 1. All gaskets, seals, and O-rings should be re- placed when an engine is overhauled. All gasket surfaces, oil seal lips, and a-rings must be cleaned. 2. Properly oil all mating parts and bearings during reassembly. Apply grease to the oil seal lips. LOCK WASHERS/PLATES AND COTTER PINS 1. All lock washers/plates CD and cotter pins must be replaced when they are removed. Lock tab(s) should be bent along the bolt or nut flat(s) after the bolt or nut has been pro- perly tightened. BEARINGS AND OIL SEALS 1. Install the bearing(s) CD and oil seal(s) @ with their manufacturer'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 light-weight lithium base grease to the seal lip(s). Oil the bearings libe- rally when installing. Do not use compressed air to spin the bearings dry. This causes damage to the bearing surfaces. '-2
I~~I"'I SPECIAL TOOLS 300·001 '·3 CIRCLIPS 1. All circlips should be inspected carefully be- fore reassembly. Always replace piston pin clips after one use. Replace distorted cir- clips. When installing a circlip CD , make sure that the sharp edged corner ® is positioned opposite to the thrust @ it receives. See the sectional view. @Shaft SPECIAL TOOLS The proper special tools are necessary for com- plete and accurate tune-up and assembly. Using the correct special tool will help prevent damage caused by the use of improper tools or impro- vised techniques. FOR TUNE UP 1. I nductive Tachometer PIN YU-08036 This tool is needed for detecting engine rpm. 2. Inductive Timing Light PIN YM-33277 This tool is necessary for checking ignition timing. 3. Compression Gauge PIN YU-33223 This gauge is used to measure the engine com- pression.
SPECIAL TOOLS 4. Fuel Level Gauge PIN YM·01312·A This gauge is used to measure the fuel level in the float chamber. 5. Valve Adjusting Tool PIN YM-08035 This tool is necessary for adjusting the valve clearance. FOR ENGINE SERVICE 1. Valve Spring Co")pressor PIN YM·04019 This tool is needed to remove and install the valve assembl ies. 2. Slide Hammer Set PIN YU-Ol083 These tools are used when removing the rocker arm shaft. 3. Flywheel Puller PIN YM-01404 This tool is used to remove the CDI rotor. 1-4
This manual is an essential resource for maintaining and repairing your Yamaha Big Bear 350. With over 400 pages of valuable information, it is the same manual used by professional mechanics at your local dealer. Whether you are a professional mechanic or a DIY enthusiast, this factory service manual covers a wide range of topics including general information, maintenance, specifications, periodic checks and adjustments, engine, carburation, drive train, chassis, electrical, and troubleshooting.