Yamaha Grizzly 450 EPS YFM45FGA, YFM45FGHA, YFM45FGPA, and YFM45FGPHA ATV 2011 Service Manual (LIT-11616-24-39)

• Covers the 2011 Grizzly 450 4WD: YFM45FGA / YFM45FGHA (non-EPS) and YFM45FGPA / YFM45FGPHA (EPS).
• Electric Power Steering (EPS) diagnosis covers warning-light fault codes, stored fault history, torque-sensor checks, and motor continuity and insulation tests.
• Final gear case repair includes pinion-bearing replacement, shim selection, ring-gear thrust-clearance checks, and backlash and stopper adjustment.
• The wet multiple-disc rear brake section covers internal friction-plate and brake-plate inspection, with rear brake lever and pedal adjustments.
• Steering stem and EPS unit removal/installation, pitman-arm indexing, and steering-tension adjustment are detailed separately from the electrical checks.
• Engine repair extends to cylinder-head and valve work, piston and cylinder inspection, crankcase separation, and transmission disassembly.
• Primary and secondary sheave service, centrifugal-clutch inspection, and middle-gear adjustment cover the belt-drive and shaft-drive assemblies.

Manual Coverage and Workshop Utility

This is an 851-page PDF set: a 685-page service compilation and a 166-page Owner’s Manual. The 2011 supplement is the First Edition, August 2010. Yamaha specifies using it with the base manual and earlier supplements included here. Coverage also identifies the cast-wheel YFM45FGPA configuration by model code 1CT8.

The service count includes two additional cover/blank pages. Earlier rear-axle and rear-brake layouts remain in the reference manuals; the 2011 supplement provides the updated procedures for these assemblies.

The separate Owner’s Manual covers YFM45FGB / YFM45FGHB, First Edition, April 2011. It explains operating controls, pre-ride checks, cargo and towing limits, routine maintenance, starting and overheating troubleshooting, and storage. Its model coverage differs from the 2011 service supplement.

EPS Diagnostics and Electrical Reference

The EPS System Block Diagram explains how steering torque and vehicle-speed inputs relate to assist control. Diagnostic coverage distinguishes normal heat-related assist reduction from system faults and includes fault-code clearing and post-repair checks.

An EPS System Circuit Diagram and separate 2011 wiring diagrams for EPS and non-EPS machines support connector and harness fault tracing. Cable-routing drawings identify the EPS motor and torque-sensor leads, grounds, relay wiring, and breather-hose paths.

Yamaha warns that disassembling the EPS unit can damage it. Coverage is testing and complete-unit replacement, not internal EPS overhaul.

Engine, Cooling and Chassis Repair

The engine sections cover the 421 cm³ liquid-cooled single-cylinder engine and include valve-clearance and compression checks. Mikuni BSR33 carburetor coverage goes into float and fuel-level adjustment, diaphragm inspection, and needle-valve service.

Radiator-cap pressure testing, thermostat checks, and water-pump seal and bearing service are supported by Coolant Flow Diagrams; Oil Flow Diagrams trace the engine lubrication circuit.

Chassis procedures add front brake master-cylinder and caliper repair, hydraulic bleeding, suspension-arm and ball-joint work. Front differential gear-motor testing and installation are covered, along with drive-select cable and shift-rod adjustments.

Specifications and Technical Data

Reference tables give component-specific tightening torques—including the pitman arm and steering-stem fasteners—along with wear limits, fluid capacities, approved lubricants, and brake pedal height and final gear backlash specifications. Emission-control and general lubrication charts lay out scheduled maintenance. Electrical tables distinguish EPS and non-EPS magneto, CDI, charging-system, and regulator specifications.

Special-tool references include shim setting tool 90890-01562 and gear lash measurement tool 90890-01467 / YM-01467. The EPS steering-tension procedure identifies 90890-03170 / YM-03170, listed as a belt-tension gauge.

The final-drive section warns that insufficient backlash can destroy gear teeth, making its shim-selection and clearance procedures important after internal final-drive repair.

Keep in mind that working on steering and drivetrain systems carries inherent risks. To ensure your safety and the reliable operation of the vehicle, carefully verify the OEM parameters and specifications in the applicable manual before starting any physical repairs or adjustments.