1997–1999 Yamaha YFM350FWBJ ATV Service Manual (P/N LIT-11616-10-58)

This Yamaha service manual package for 1997–1999 combines the YFM350FWBJ base manual, P/N LIT-11616-10-58, with the YFM350FWBL/YFM350FWBLC supplement, P/N LIT-11616-12-10.

Supplied as one English-language, 351-page PDF containing both publications.

• Engine repair: Engine removal, cylinder-head service, valve-clearance adjustment, crankcase disassembly, piston inspection, timing chain installation, and recoil starter repair.

• Clutch and transmission: Primary and secondary clutch inspection, shift-fork and gear checks, transmission reassembly, and middle gear service.

• Carburetor overhaul: Mikuni BST34 disassembly, piston-valve and coasting-enricher inspection, float-height checks, and fuel-level adjustment.

• Shaft drive: Differential gear service, constant velocity (CV) joint and boot inspection, rear axle removal, and final drive pinion and ring gear shimming.

• Brakes and chassis: Hydraulic front drum brake repair, supplementary front disc brake procedures, rear brake service, toe-in adjustment, and swingarm maintenance.

• Electrical diagnostics: C.D.I. ignition, starting, charging, lighting, and signal-system tests, with wiring diagrams and troubleshooting charts.

Yamaha wrote these publications for its dealers and qualified mechanics who already understand mechanical principles and repair procedures.

Model Codes and Supplement Coverage

The base manual identifies 4WU1 (USA) and 4WU2 (Canada) as model codes. The supplement covers 5FT1 (USA) and 5FT2 (California), with revised front brakes, steering geometry, suspension data, clutch spring limits, and electrical test specifications.

California coverage: Complete service information for the California configuration also requires the separate YFM350FWBKC supplement, LIT-11616-10-93. That publication is not included in this PDF.

Engine and Carburetor Repair

Engine overhaul coverage includes piston-to-cylinder clearances, valve assembly specifications, intake and exhaust cam lobe dimensions, and cam chain timing. The Crankshaft and Transmission exploded view accompanies crankshaft installation, balancer assembly, and internal gearbox procedures.

Mikuni BST34: The carburetor chapter covers the main and pilot jets, needle valve and valve seat, float, and starter plunger. Fuel-level measurement uses the listed Yamaha gauge YM-01312-A / 90890-01312.

Shaft Drive Diagnosis and Gear Setup

The shaft-drive Troubleshooting Chart separates wheel-bearing, CV-joint, rear brake, and rear axle checks, helping a mechanic narrow down driveline noise before dismantling the final drive.

Gear setup includes separate middle drive and driven gear shim calculations, final-drive thrust-washer selection, and differential preload checks. The gear lash procedures identify measurement tool YM-01231 / 90890-01231.

Yamaha warns that overtightening the ring-gear holding bolt during final gear lash measurement can damage the ring gear. The internal differential gear assembly is factory assembled and is not intended for internal disassembly.

Brake and Chassis Variants

Front drum brake lining inspection and hydraulic bleeding belong to the base manual. The supplement adds front disc brake pad replacement, caliper and master-cylinder repair, and disc thickness and runout checks.

Steering adjustments, shock absorber settings, and swingarm service are accompanied by revised front-end specifications in the supplement. Brake seal handling is also covered: the manual warns that cleaning internal brake components with solvents can swell and distort the seals.

Always rely on the complete original OEM documentation and proper workshop protocols before initiating any hands-on mechanical work.

Electrical Tests, Diagrams, and Specifications

Starting-circuit diagnosis covers the cut-off relay, gear-position switch, rear brake switch, and C.D.I. unit. Separate checks address starter-motor wear, ignition coils, charging output, lighting faults, and the oil-temperature warning circuit.

The YFM350FWB Wiring Diagram and Electrical Starting System Circuit Diagram show circuit connections and wire codes. Cable Routing and Lubrication Diagrams document harness placement and engine oil paths.

Engine, chassis, and electrical reference tables provide cylinder-head warpage and compression limits, valve clearances, component tightening torques, fluid capacities, and wear limits; tightening-sequence drawings cover the cylinder head and crankcase.

PDF Contents and Navigation

The 317-page base manual includes 14 front-matter pages, two repeated maintenance pages, one blank steering-system page, and the full wiring diagram; the 34-page supplement includes six front-matter pages, all within the stated total. Seventeen embedded PDF bookmarks link to the main chapters and supplement sections, but PDF text search is not available. The full wiring diagram is readable when enlarged; some small connector codes in the chapter diagrams remain blurred.