1999 Yamaha YFM400FWAM / YFM400FWAMC & YFM400AM / YFM400AMC Kodiak 400 ATV Service & Repair Manual Set (P/N LIT-11616-13-21, LIT-11616-13-39)

The supplement introduces model-specific service information and is intended to be used with the included base manual.

Supplement coverage: The included supplement ends after the Middle Gear section. Its later chassis sections and YFM400AM/YFM400AMC wiring diagram, listed in its contents, are not included in this PDF.

Engine, Shaft-Drive and Electrical Service

• Engine repair: Step-by-step engine removal, cylinder-head service, valve and valve-guide inspection, piston inspection, crankcase separation, and crankshaft installation procedures.

• Automatic transmission and clutch: Primary and secondary sheave disassembly, centrifugal-clutch inspection, internal transmission checks, shift-fork inspection, and selector adjustment.

• Shaft drive: Constant velocity joint service, differential inspection, rear-axle removal, final-drive bearing replacement, shim selection, and gear-lash adjustment.

• Carburetor service: Mikuni carburetor teardown, diaphragm and jet inspection, float-height measurement, fuel-level adjustment, and configuration-specific carburetor specifications.

• Cooling system: Radiator-cap pressure testing, thermostat inspection, water-pump disassembly, seal installation, and coolant replacement procedures.

• Brakes and chassis: Brake-pad replacement, master-cylinder and caliper service, hydraulic bleeding, steering inspection, toe-in adjustment, and swingarm checks.

• Electrical diagnosis: Ignition, starting, charging, lighting, cooling-fan, and selectable four-wheel-drive circuit diagrams with component tests and troubleshooting charts.

Yamaha wrote these manuals primarily for dealers and qualified mechanics, assuming an existing understanding of mechanical principles and machine repair.

Engine Overhaul and Carburetor Detail

The engine chapter goes beyond routine maintenance, with valve-seat inspection and refacing, valve-guide replacement, piston-ring measurements, oil-pump clearances, and crankshaft and balancer installation. Exploded assembly views are paired with job instruction charts and component-specific inspection limits.

The centrifugal-clutch section includes one-way-bearing orientation and engagement checks; starter-clutch inspection is covered separately. Recoil-starter disassembly and spring assembly are also documented.

Separate California and non-California carburetor specifications distinguish jetting and needle configurations. Fuel-level checking is illustrated with the specified gauge, rather than relying on float-height data alone.

Middle Gear, Differential and Final Drive

Middle-gear procedures include shim calculations based on component markings and gear-lash measurement. The tool references identify the sheave spring compressor YM-04134 and middle-gear lash measurement tool YM-01467 for their respective jobs.

Left-hand-thread warnings for the middle driven shaft bearing retainers identify a thread-damage risk during disassembly. U-joint assembly notes explain how displaced bearing needles prevent full yoke seating and can be damaged if assembly is forced.

Differential coverage includes gear inspection, backlash adjustment, and operating checks. Yamaha specifically warns against disassembling the factory-assembled internal differential unit.

Cooling, Brakes and Reassembly References

Water-pump service covers the impeller, rubber damper, bearing, oil seal, and mechanical seal. Brake procedures distinguish front and rear master cylinders and calipers, with seal-replacement requirements and hydraulic bleeding instructions.

Factory cable-routing drawings and coolant- and oil-flow diagrams provide references for restoring hose and harness layouts during reassembly. Brake and cooling-system work requires the manual’s precautions for hydraulic fluid and hot, pressurized coolant.

Electrical Fault Tracing

The electrical chapter combines circuit diagrams, connector illustrations, continuity checks, and component tests. Starting-circuit coverage explains the neutral, park, and rear-brake interlocks, helping technicians distinguish control-circuit faults from starter-motor problems.

The four-wheel-drive section includes gear-motor testing and switch checks. Separate troubleshooting references address hard starting, poor idle, shifting faults, clutch slipping, overheating, and unstable handling.

A Preview of Valve, Idle and Electrical Specifications

Cold valve-clearance specifications distinguish intake clearance of 0.06–0.10 mm from exhaust clearance of 0.16–0.20 mm. Idle-speed adjustment is specified at 1,450–1,550 r/min.

The cylinder-head torque table lists 40 Nm for the M10 bolts, with separate specifications for the smaller fasteners and staged-tightening instructions in the installation section. Electrical reference data include a 30 A main fuse alongside individual circuit-fuse ratings.

PDF Bookmarks, Diagram Detail and Included Pages

Search, navigation and diagram detail: PDF text search is not available. Embedded bookmarks provide chapter and supplement navigation. Small wiring labels require enlargement, and some lettering in the starting-system diagram remains faint.

Both publications are combined in one printable, English-language, 374-page PDF. The total includes one separate identification sheet in addition to the publication page counts above.