2004 Polaris Sportsman 400 & 500 ATV Service Manual (P/N 9918802)

This service manual covers the 2004 Polaris Sportsman 400 and 500 ATVs, including standard and Hunter Edition configurations, with separate early- and late-production procedures. Service-manual reference: P/N 9918802.

• Engine repair: Engine removal and installation, cylinder-head service, valve-seat reconditioning, crankcase disassembly, crankshaft inspection, camshaft timing, and recoil-starter overhaul.

• Fuel and carburetion: Mikuni BST carburetor disassembly and inspection, float adjustment, needle-and-seat leakage testing, fuel-pump service, and late-model fuel-sender procedures.

• PVT clutching: Non-EBS and EBS clutch inspection, bushing replacement, drive-belt service, clutch alignment, and separate early- and late-model driven-clutch procedures.

• Final drive: AWD hub and front-gearcase service, magnetic-coil inspection, driveshaft removal, CV-joint boot replacement, and rear hub and bearing work.

• Transmission service: Separate early- and late-model removal, internal disassembly, reassembly, gear-selector service, gear-backlash adjustment, and troubleshooting sections.

• Chassis and brakes: Body-panel removal, steering and A-arm service, MacPherson strut replacement, hydraulic brake bleeding, master-cylinder work, and caliper overhaul.

• Electrical diagnosis: DC/CDI ignition, ETC switch, stator, charging, coolant-sensor, and starter testing, with early/late wiring diagrams and Hunter Edition accessory circuits.

This manual is suited to experienced ATV mechanics with precision measuring and electrical test equipment; it specifies certified Polaris Master Service Dealer technicians for PVT maintenance and repair.

Early/Late AWD, Transmission, and EBS Differences

Early models use electrically engaged Hilliard front hubs, while late models use a Centralized Hilliard front gearcase. Separate procedures help you match the AWD components and diagnostic information to the hardware on the machine before selecting parts or tests.

The transmission sections distinguish the early external shift-selector arrangement from the late drum-shift design. Internal coverage includes shaft and gear inspection, output-housing assembly, backlash settings, and exploded transmission views.

EBS clutch service: The early and late driven clutches have separate disassembly and bushing-service sections. Altitude-specific clutch charts identify the documented weight, spring, and helix combinations.

The EBS sections warn that incorrect driven-clutch disassembly can damage the one-way clutch seals. Early AWD hub service also identifies the risk of overstressing the Hilliard garter spring, which can allow unintended hub engagement at speed; the specified installation tool is P/N 2870888.

Engine, Lubrication, and Cooling Repair

Engine service data separates EH42PLE and EH50PLE inspection specifications. The repair chapters cover rocker arms, camshaft journals, valve guides and seats, piston-to-cylinder clearance, crankshaft runout, bearing installation, and shaft end-play adjustment.

The EH50PL oil-flow diagram explains the lubrication circuit. Related procedures address oil-pump inspection and priming, cylinder honing, engine-mount fasteners, and the complete cylinder-head tightening sequence.

Water-pump seal access: The EH50PL procedure describes mechanical-seal replacement with the engine installed using puller P/N 2872105, avoiding engine removal and crankcase separation for that operation. Cooling-system coverage includes pressure testing, thermostat information, and overheating troubleshooting.

The sealed recoil-starter section includes spring, reel, drive-tab, and housing inspection rather than only external starter maintenance.

Mikuni Carburetors, Suspension, and Hydraulic Brakes

BST 34 and BST 40 exploded views support carburetor identification and internal inspection. The fuel chapter explains vacuum-slide operation and separates lean-mixture, rich-mixture, and poor-idle troubleshooting; jetting charts relate the specified main jets to altitude and ambient temperature.

Body and steering coverage includes rack and headlight-pod assemblies, early/late strut views, ball-joint replacement, steering-post service, and wheel alignment. The steering section recommends authorized Polaris MSD technicians for repair and adjustment.

Brake procedures distinguish banjo-style and pipe-style connections. Coverage extends to disc inspection, front and rear caliper service, auxiliary master-cylinder replacement, and hydraulic bleeding.

Always consult a certified technician prior to performing major structural or engine maintenance on your equipment.

Ignition, Charging, and Hunter Edition Circuits

Electrical troubleshooting separates the early and late systems. The late-model ECM section explains its rectifier/regulator, engine-temperature controller, and protected circuit outputs, alongside thermistor and fan-control tests.

Ignition and charging-system flowcharts support fault isolation, while starter troubleshooting includes voltage-drop checks, brush inspection, armature testing, and starter-drive service.

Hunter Edition equipment: Warn winch coverage includes assembly views, switch installation, and basic wiring. Hand/thumb-warmer testing and a dedicated accessory schematic cover the Hunter package circuits.

A Preview of Valve, End-Play, and Fluid Specifications

These examples are a small selection of the engine and drivetrain data in the manual. Intake and exhaust valve clearance is specified at 0.006 in. (0.15 mm) with the engine cold. The crankshaft assembly section gives an end-play range of 0.008–0.016 in. (0.02–0.04 cm).

The model specification tables list 32 oz. of transmission fluid, while the maintenance instructions specify approximately 20 oz. at a lubricant change. The change quantity therefore has its own stated service context.

Text Search, Wiring Detail, and PDF Contents

Search and diagram navigation: Body text is searchable, but labels inside the large wiring diagrams are outside the searchable text layer. Embedded bookmarks cover the main chapters and many subtopics; some topic links open a contents or Notes page. Small wire codes and connector labels on the inspected diagrams are readable when enlarged, and rotating the sideways schematics makes them easier to follow.

Delivered as one printable English PDF with 343 pages. That total already includes the opening chapter overview, five blank or Notes pages, and the seven-page index.