Yamaha Big Bear 350 YFM350FW ATV 1987–1999 OEM Service Manual (P/N 4WU-W0747-00-AD)
Yamaha Models Covered & Key Technical Specifications
Models: Big Bear 350 (YFM350FW)
Sub-models / Variants: 2WD, 4WD (referenced by series documentation)
Model Years: 1987–1999
Serial Numbers: JY41YW00HC000101, 1YW-000101
Technical Data:
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Engine displacement: 350 cc class
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Cylinder bore: 82.97–83.02 mm
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Compression pressure: 785–834 kPa (114–121 psi)
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Engine oil capacity: 1.5 liters
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Final gear oil capacity: 0.13 liters
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Idle speed: 1,450–1,550 r/min
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Spark plug: D8EA (NGK) or X24ES-U (ND)
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Valve clearance (Intake): 0.06–0.10 mm
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Valve clearance (Exhaust): 0.16–0.20 mm
Yamaha Manual Features & Content Preview
This 294-page official Yamaha OEM manual provides the complete reference data needed for servicing the 1987–1999 Big Bear 350 (YFM350FW). Whether you manage a busy powersports shop or handle your own routine maintenance, this digital guide delivers the exact factory specifications for powertrain and chassis work across the 1YW and 4WU-series production builds.
- Publication Number: Official OEM P/N 4WU-W0747-00-AD.
- Visual Reference: Includes 47 exploded-view diagrams to simplify component identification and verify correct assembly order.
- Fastener Specifications: Features 35 torque-specification tables covering critical engine and chassis hardware.
- Model-Specific Data: Covers diagnostics tied strictly to the 1YW-000101 serial-number range for the 350-series engine.
Documentation Scope & Technical Depth
The manual spans eight primary chapters, starting with machine identification and special tool requirements. It outlines the exact factory parameters for periodic inspections, including valve clearance adjustments, throttle linkage calibration, and ignition timing verification.
For deeper powertrain work, the document covers complete engine overhaul protocols. You get clear component limits and clearance specs for disassembling and rebuilding the cylinder head, clutch assemblies, and transmission. For instance, the reference data specifies a 10 Nm torque rating for tappet covers and a 115 Nm requirement for the main bearing cap. Additional inspection data lists the oil gallery bolt at 7 Nm. You will also find precise tool callouts, such as the YM-01404 flywheel puller, ensuring you have the right gear on the bench before tearing down the block.
Always prioritize shop safety. The specifications and limits discussed here serve as a structural overview of the manual. Always verify torque figures and procedures directly against the full OEM documentation before applying force or running diagnostics to prevent equipment damage or personal injury.
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