Yamaha Bruin 350 2003–2008 Service & Repair Manual (OEM)

This 481-page PDF combines two Yamaha factory publications into one repair reference for the Bruin 350/YFM350AS: the YFM400FAR Service Manual, LIT-11616-16-02 / 5TE-F8197-10, and the YFM350AS Supplementary Service Manual, LIT-11616-17-33 / 5WH-F8197-10. Yamaha directs technicians to use the YFM350AS supplement with the YFM400FAR base manual. The base volume supplies shared repair procedures, while the supplement adds or replaces the 350-specific data. Pages 1–364 contain the base volume; pages 365–481 contain the YFM350AS supplement.

• Exact 350 application: YFM350AS, model code 5WH1; the supplement is the First Edition dated August 2003.
• Machine configuration: 348 cc air-cooled SOHC single, Mikuni BSR33 carburetor, electric and recoil starting, wet centrifugal automatic clutch, V-belt automatic transmission, reverse, and shaft final drive.
• Repair format: specifications, service limits, tightening torques, exploded job charts, special-tool references, diagnostic checks, circuit diagrams, and the full YFM350AS wiring diagram.

Component and System Documentation

The supplement repeatedly sends the technician to the YFM400FAR base volume for procedures shared by both machines, and those referenced pages are already included in this file. Engine coverage includes removal, top-end repair, A.C. magneto and recoil-starter service, carburetor work, and balancer, oil-pump, and oil-cooler repair. Drivetrain and chassis sections cover primary and secondary sheaves, clutch repair, crankcase separation, crankshaft installation, transmission assembly, middle-gear shimming, rear final-drive setup, brake work, steering, and suspension. The electrical chapters support starting, charging, lighting, warning-circuit, and fault diagnosis.

For heavy repair work, the YFM350AS section adds model-specific exploded views and job charts for the primary and secondary sheaves, crankcase and transmission, and middle drive and driven gears. Rear drum brake, steering stem, tie-rod, and front-arm assemblies receive the same treatment. The charts identify removal order, part quantity, replacement items, lubrication points, thread-lock locations, wear checks, and torque callouts. That layout gives a technician the component sequence and inspection data needed for disassembly and reassembly without treating the publication as a generic owner-maintenance guide.

Model distinction matters with this combined reference. The 5TE1/5TE5, 401 cc liquid-cooled engine, radiator-capacity data, front differential, and on-command 2WD/4WD system belong to the YFM400FAR base volume. For the Bruin 350 application, use the YFM350AS 5WH1 specifications and supplement changes. Its “Cooling System” electrical section deals with the oil-cooler fan, fan relay, thermo unit, and oil-temperature warning circuit rather than a liquid-coolant system.

Technical Data, Tools, and Repair Notes

The 350 tables specify an 83.0 × 64.5 mm bore and stroke and a 9.2:1 compression ratio. Engine-oil quantities are 2.2 L for a periodic change, 2.3 L with filter replacement, and 3.1 L total; final-gear oil is 0.23 L for a change and 0.25 L total. Cold valve clearance is 0.06–0.10 mm intake and 0.16–0.20 mm exhaust. CVT and drivetrain data include a 1.0 mm clutch-shoe wear limit, 1,950–2,350 rpm clutch engagement, 0.1–0.3 mm middle-gear backlash, and 0.1–0.2 mm final-gear backlash. Chassis tables add brake wear limits, wheel runout, toe-in, suspension travel, and fastener torques.

Electrical data extend well beyond a color-coded schematic. The manual provides charging output and regulated-voltage ranges, ignition and charging-coil resistance, starter-motor dimensions, fuse ratings, diode checks, and thermo-unit resistance at test temperature. Troubleshooting covers hard starting, poor idle or high-speed performance, clutch slipping, no-move complaints, hard shifting, jumping out of gear, overheating, weak braking, unstable handling, charging and lighting faults, oil-temperature warning operation, and fan-motor control.

Named visual references include “Oil Flow Diagrams,” “Cable Routing,” the “Primary and Secondary Sheaves” exploded view, “Selecting the Middle Drive and Driven Gear Shims,” the “Signal System Circuit Diagram,” and the full-page “YFM350AS Wiring Diagram.” Listed tools include the YU-90050 crankshaft installer set, YU-01135-A / 90890-01135 crankcase separating tool, and the secondary-sheave service set: YM-04134 / 90890-04134 spring compressor, YM-04135 / 90890-04135 fixed block, and YM-01348 / 90890-01348 locknut wrench.

Three repair cautions show why the model-specific pages matter. The 400 base procedure shows 40 N·m for its M10 cylinder-head bolts. The YFM350AS table instead calls for 32 N·m on the four M10 bolts and 20 N·m on the two M8 bolts; using the base value on the 350 can over-torque the head fasteners. Before the crankcase bolts are tightened, the transmission must shift and rotate freely, or a mis-seated fork or gear can be trapped and damaged inside the cases. Replacing a middle gear, bearing housing, or crankcase requires recalculating the drive and driven shims; incorrect shim thickness changes gear mesh and can damage gears and bearings.

Support the ATV securely before chassis work, follow Yamaha’s warnings and specified torque values, and use the correct service tools. Brake, steering, CVT, electrical, and internal-engine repair should be performed only by someone with the mechanical knowledge assumed by the publication.