1990 Yamaha YFM350XA Warrior 350 ATV Factory Service Manual with Supplements (P/N 3GD-28197-12)

This Yamaha Service Division manual covers the 1990 YFM350XA Warrior 350 ATV, model code 3GD5. The main publication is LIT-11616-07-50 / 3GD-28197-12. Included supplements provide additional service information for the YFM350XE, YFM350XJ, California-spec YFM350XKC, and YFM350XP.

• Engine and transmission: Engine removal, crankcase splitting, cylinder-head repair, clutch inspection, and constant-mesh transmission disassembly and assembly.

• Lubrication and balancer: Trochoid oil pump inspection, lubrication diagrams, and assembly references for the primary drive and balancer driven gear.

• Carburetion: Mikuni BTM36SH disassembly, inspection, and assembly, with float-height and fuel-level adjustments and accelerator-pump circuit illustrations.

• Brakes and steering: Caliper and master-cylinder repair, hydraulic brake bleeding, steering-knuckle inspection, and toe-in adjustment.

• Suspension and chain drive: Double wishbone front suspension and swingarm linkage inspection, shock absorber preload and damping adjustments, and drive chain slack adjustment.

• Electrical diagnosis: CDI magneto ignition, charging and starter-interlock testing, lighting and signal-system troubleshooting, and wiring diagrams.

Written primarily for Yamaha dealers and their qualified mechanics, this manual assumes an understanding of mechanical principles and machine repair procedures.

Engine Overhaul and Assembly References

The main manual’s eight chapters combine periodic maintenance schedules with component-specific torque tables, wear limits, and illustrated repair procedures. Engine coverage extends to valve-seat refacing, valve-guide replacement, piston and ring inspection, crankshaft checks, and cam timing.

Transmission and Shifter exploded views identify the gear assemblies, shift forks, and reverse mechanism. Lubrication diagrams and illustrated symbols identify oil passages, lubrication points, locking agents, and replacement requirements for seals and gaskets.

Special-tool references include crankcase separator YU-01135 with adapter YM-1382 and crankshaft installer set YU-90050, showing which dedicated tools the internal engine work calls for.

Carburetor Inspection and Routine Adjustments

The carburetor section includes needle-valve and coasting-enricher diaphragm inspection. Its section view illustrates the fuel, starter, and accelerator-pump circuits, while the wire-cylinder section covers the linkage between the throttle, piston-valve, and throttle-valve cables.

Routine service coverage includes valve-clearance adjustment, ignition-timing checks, engine oil and filter service, and lubrication schedules for the powertrain, suspension, and drive chain.

Brake, Hub, and Suspension Service

Chassis procedures extend to wheel-bearing replacement, rear axle removal, axle ring-nut installation, and inspection of the relay arm, connecting arm, bushings, and swingarm pivot.

The rear axle section specifically warns that direct hammer blows can damage the axle threads and splines. Its assembly illustrations and tool references accompany the removal and installation procedures.

Working on heavy ATV components requires correctly rated supports and lifting equipment. The rear shock absorber contains highly pressurized nitrogen gas and has specific handling precautions.

Starter Interlocks and Electrical Fault Tracing

The Electric Starting System circuit diagram and switch-continuity charts explain how the clutch, neutral, and selector switches interact with the starting circuit cut-off relay. This helps distinguish an interlock fault from a starter-motor problem before parts are replaced.

Separate troubleshooting charts address no spark, charging faults, lighting failures, and neutral/reverse indicators. Wiring diagrams and cable-routing drawings support circuit identification. The starting-system section also warns that applying battery voltage directly to the CDI unit during testing can damage it.

What the Included Supplements Add

YFM350XE: Revised fuel-capacity and rear-wheel specifications, cable routing, and throttle-cable adjustment information.

YFM350XJ: Updated engine and electrical specifications, revised routing diagrams, and coverage of the parking-brake engine revolution limiter.

YFM350XKC: California-specific carburetor identification and calibration data, together with maintenance schedules.

YFM350XP: Separate California and non-California model codes, DC CDI ignition diagnosis, rotor rotation direction detection-coil testing, brake-light circuit checks, and updated front-suspension information.

These supplements document changes for their respective variants and are used with the main manual for complete service procedures.

A Preview of Valve and Brake Specifications

These examples represent a small selection of the main YFM350XA manual’s inspection and adjustment data. Cold valve clearance is specified as 0.06–0.10 mm at the intake and 0.16–0.20 mm at the exhaust.

The chassis specifications list a 161 mm front brake disc outside diameter. The related brake sections cover disc-condition checks, wear limits, and hydraulic service.

PDF Search, Chapter Access, and Included Documents

Search and diagram access: Text search is available in the YFM350XP supplement; the main manual and other supplements are not text-searchable. Embedded bookmarks cover the main chapters and supplements, although the XP chassis bookmark opens one page early. Small wiring labels are readable when enlarged; the XJ wiring sheet is oriented sideways.

Supplied as one printable, English-language 333-page PDF: YFM350XA main manual, 265 pages; YFM350XE supplement, 11 pages; YFM350XJ supplement, 20 pages; YFM350XKC supplement, 9 pages; and YFM350XP supplement, 28 pages. These counts already include 35 cover and introductory pages, one manufacturer back cover, and three otherwise blank section-ending pages.