Yamaha Big Bear 350 ATV Service Manual Set, 1997–1999 (P/N LIT-11616-10-58)

Use the base manual for the main service procedures and the supplement for model-specific changes to the front brakes, steering geometry, suspension, clutch spring limits, and electrical test specifications.

Complete service information for the California configuration also requires the separate YFM350FWBKC Supplementary Service Manual (LIT-11616-10-93), sold separately from this PDF.

PDF Bookmarks and Wiring Detail

Navigation and diagram detail — Seventeen embedded bookmarks link to the main chapters, the full wiring diagram, and the supplement sections. PDF text search is unavailable. The full wiring diagram is readable when enlarged, though some small connector codes in the chapter diagrams remain blurred.

Both publications are supplied as one printable English-language PDF with 351 pages. The total includes 14 front-matter pages in the base manual and six in the supplement, plus two repeated maintenance pages, one steering-system page with no procedure text, and the full wiring diagram in the base manual.

Engine, Driveline, Brake, and Electrical Service

This selection of service topics shows the range of procedures covered. The base manual also includes speed-limiter adjustment and headlight beam adjustment.

• 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 — Carburetor 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 service, rear brake service, toe-in adjustment, and swingarm maintenance.

• Electrical diagnostics — C.D.I. ignition, starting, charging, lighting, and signal-system tests, supported by circuit diagrams and troubleshooting charts.

Yamaha wrote both publications for its dealers and qualified mechanics familiar with mechanical principles and repair procedures.

Engine Overhaul and Carburetor Checks

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

The carburetor chapter covers the main and pilot jets, needle valve and seat, float, and starter plunger. It identifies Yamaha fuel-level gauge YM-01312-A / 90890-01312 for the fuel-level check.

Shaft Drive Diagnosis and Gear Setup

The shaft-drive troubleshooting chart separates wheel-bearing, CV-joint, rear brake, and rear axle checks to help narrow down driveline noise before dismantling the final drive.

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

Yamaha warns that overtightening the holding bolt during final gear lash measurement can damage the ring gear. The differential gear assembly must remain assembled as a factory-set unit.

Front Drum and Disc Brake Service

The base manual covers front drum brake lining inspection and hydraulic bleeding. The supplement covers front disc pad replacement, caliper and master-cylinder repair, disc thickness and deflection checks, and revised front and rear shock absorber settings.

Yamaha warns that solvents can swell and distort internal brake seals. Always rely on the complete original OEM documentation and proper workshop protocols before initiating any hands-on mechanical work.

Electrical Tests and Reference Diagrams

Starting-circuit diagnosis covers the cut-off relay, gear-position switch, rear brake switch, and C.D.I. unit. Separate checks cover 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 connections and wire codes. Cable routing and lubrication diagrams show harness placement and engine oil paths.

The reference tables include cylinder-head warpage and compression limits, tightening torques, fluid capacities, and component wear limits. Tightening-sequence drawings cover the cylinder head and crankcase.

Valve Clearance and Front Disc Inspection Examples

The YFM350FWBJ base manual specifies cold valve clearance of 0.06–0.10 mm at the intake and 0.16–0.20 mm at the exhaust.

For the YFM350FWBL and YFM350FWBLC front disc brake, the supplement specifies a minimum disc thickness of 3.0 mm and maximum disc deflection of 0.15 mm measured with a dial gauge.