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

This service manual covers the 2004 Polaris Sportsman 400 and 500 ATVs, including standard and Hunter Edition configurations. It identifies the midyear changes and labels the procedures that differ between early and late models. Polaris service manual reference: P/N 9918802.

Text Search, Bookmarks, and Wiring Diagrams

Search and diagram detail: The manual text is searchable. Wire codes and connector labels on the foldout schematics are outside the search layer and are readable in the inspected areas when enlarged. Rotating the sideways diagrams makes them easier to follow. Embedded bookmarks link to the main chapters and many subtopics, although some topic links land on a chapter contents or notes page.

The download is one printable English PDF with 343 pages, including the opening chapter overview, five blank or notes pages, and a seven-page index.

Engine, Drivetrain, and Electrical Service

These selected topics illustrate the manual’s service coverage. The manual also includes periodic inspection and lubrication schedules and instrument-cluster troubleshooting.

• Engine repair: Engine removal and installation, cylinder-head service, valve-seat reconditioning, camshaft timing, crankcase disassembly, crankshaft inspection, and sealed recoil-starter overhaul.
• Fuel and carburetion: Mikuni BST disassembly and inspection, float adjustment, needle-and-seat leakage testing, fuel-pump service, and late-model fuel-sender removal and installation.
• PVT clutching: EBS and non-EBS clutch inspection and bushing service, belt service, clutch alignment, and separate early- and late-model EBS driven-clutch procedures.
• Final drive: AWD hub and front-gearcase repair, magnetic-coil inspection, driveshaft removal, CV-joint boot replacement, and rear hub and bearing service.
• Transmission service: Early- and late-model removal, internal disassembly and reassembly, shift-selector service, output gear backlash adjustment, and troubleshooting.
• Chassis and brakes: Body-panel removal, steering and A-arm service, MacPherson strut replacement, hydraulic bleeding, master-cylinder work, and caliper overhaul.
• Electrical diagnosis: DC/CDI ignition, electronic throttle control, stator, charging, coolant-sensor, and starter tests, plus early- and late-model wiring diagrams and Hunter Edition accessory circuits.

The manual is suited to experienced ATV mechanics with precision measuring and electrical test equipment. Polaris specifies a certified Polaris Master Service Dealer technician for PVT maintenance and repair.

Early and Late AWD, Transmission, and EBS

Early models use electrically engaged Demand 4 Hilliard front hubs. Late models use a Centralized Hilliard front gearcase. The identification illustrations show the shifter, transmission, and AWD differences so you can match the procedure to the hardware before ordering parts or choosing a diagnostic test.

The transmission chapter includes exploded views of both designs. It covers the early external shift selector, the late drum-shift assembly, shaft and gear inspection, and output housing assembly.

The EBS sections distinguish the early and late driven clutches and warn that disassembly from the wrong side can damage the one-way clutch seals. The clutch charts list shift weights, springs, and helixes by altitude.

For early AWD hubs, the manual specifies garter spring installation tool P/N 2870888. It warns that overstretching the spring can allow unintended hub engagement at speed.

Engine, Lubrication, and Cooling

Service tables give separate EH42PLE and EH50PLE inspection data for rocker arms, camshaft journals, valve guides and seats, and piston-to-cylinder clearance. The engine chapter also covers cylinder honing, crankshaft runout, bearing installation, shaft end play, engine-mount torque, and cylinder-head tightening sequences.

The EH50PL oil-flow diagram traces the lubrication circuit. Related procedures cover oil-pressure testing, oil-pump inspection and priming, and oil and filter changes. The sealed recoil-starter section covers inspection of the spring, reel, drive tab, and housing.

For the EH50PL engine, the manual describes replacing the water-pump mechanical seal with the engine installed using puller P/N 2872105. That procedure avoids splitting the crankcase for seal replacement. Cooling-system coverage also includes pressure testing, thermostat specifications, and overheating diagnosis.

Mikuni Carburetors, Steering, and Hydraulic Brakes

Exploded views show the Mikuni BST 34 and BST 40 carburetors. The fuel chapter explains vacuum-slide operation and how to troubleshoot lean running, rich running, and poor idle. Jetting charts specify main jets by altitude and ambient temperature.

Chassis illustrations cover rack and headlight-pod assemblies, early and late struts, ball joints, the steering post, and wheel alignment. Polaris recommends an authorized, certified technician for steering component repair and adjustment.

The brake chapter distinguishes banjo-style and pipe-style connections and covers disc inspection, front and rear caliper service, and auxiliary master-cylinder replacement.

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

Ignition, Charging, and Hunter Edition Wiring

The late-model ECM section explains the rectifier/regulator, engine-temperature controller, and protected circuit outputs. Thermistor and fan-control tests help isolate cooling circuit faults.

Ignition and charging flowcharts guide electrical diagnosis. The starter section includes voltage-drop checks, brush inspection, armature testing, and starter-drive service.

Hunter Edition coverage includes Warn winch assembly views, switch installation, basic winch wiring, and hand and thumb warmer testing. A dedicated schematic shows the accessory circuits.

A Preview of Valve Clearance, End Play, and Fluid Capacity

The maintenance chapter specifies 0.006 in. (0.15 mm) for intake and exhaust valve clearance with the engine cold and the piston at top dead center on the compression stroke. The EH50PL crankshaft assembly procedure specifies 0.008–0.016 in. (0.02–0.04 cm) of end play after accounting for the shim.

For both early and late Sportsman 400 and 500 models, the specification tables list a transmission capacity of 32 oz. The maintenance chapter gives approximately 20 oz. for a routine lubricant change.